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Sample records for laser altimeter designed

  1. Design and Performance Measurement of the Mercury Laser Altimeter

    Science.gov (United States)

    Sun, Xiao-Li; Cavanaugh, John F.; Smith, James C.; Bartels, Arlin E.

    2004-01-01

    We report the design and test results of the Mercury Laser Altimeter on MESSENGER mission to be launched in May 2004. The altimeter will provide planet surface topography measurements via laser pulse time of flight.

  2. Optical System Design and Integration of the Mercury Laser Altimeter

    Science.gov (United States)

    Ramos-Izquierdo, Luis; Scott, V. Stanley, III; Schmidt, Stephen; Britt, Jamie; Mamakos, William; Trunzo, Raymond; Cavanaugh, John; Miller, Roger

    2005-01-01

    The Mercury Laser Altimeter (MLA). developed for the 2004 MESSENGER mission to Mercury, is designed to measure the planet's topography via laser ranging. A description of the MLA optical system and its measured optical performance during instrument-level and spacecraft-level integration and testing are presented.

  3. Considerations in the Design of Future Planetary Laser Altimeters

    Science.gov (United States)

    Smith, D. E.; Neumann, G. A.; Mazarico, E.; Zuber, M. T.; Sun, X.

    2017-12-01

    Planetary laser altimeters have generally been designed to provide high accuracy measurements of the nadir range to an uncooperative surface for deriving the shape of the target body, and sometimes specifically for identifying and characterizing potential landing sites. However, experience has shown that in addition to the range measurement, other valuable observations can be acquired, including surface reflectance and surface roughness, despite not being given high priority in the original altimeter design or even anticipated. After nearly 2 decades of planetary laser altimeter design, the requirements are evolving and additional capabilities are becoming equally important. The target bodies, once the terrestrial planets, are now equally asteroids and moons that in many cases do not permit simple orbital operations due to their small mass, radiation issues, or spacecraft fuel limitations. In addition, for a number of reasons, it has become necessary to perform shape determination from a much greater range, even thousands of kilometers, and thus ranging is becoming as important as nadir altimetry. Reflectance measurements have also proved important for assessing the presence of ice, water or CO2, and laser pulse spreading informed knowledge of surface roughness; all indicating a need for improved instrument capability. Recently, the need to obtain accurate range measurement to laser reflectors on landers or on a planetary surface is presenting new science opportunities but for which current designs are far from optimal. These changes to classic laser altimetry have consequences for many instrument functions and capabilities, including beam divergence, laser power, number of beams and detectors, pixelation, energy measurements, pointing stability, polarization, laser wavelengths, and laser pulse rate dependent range. We will discuss how a new consideration of these trades will help make lidars key instruments to execute innovative science in future planetary

  4. Baseline Design and Performance Analysis of Laser Altimeter for Korean Lunar Orbiter

    Directory of Open Access Journals (Sweden)

    Hyung-Chul Lim

    2016-09-01

    Full Text Available Korea’s lunar exploration project includes the launching of an orbiter, a lander (including a rover, and an experimental orbiter (referred to as a lunar pathfinder. Laser altimeters have played an important scientific role in lunar, planetary, and asteroid exploration missions since their first use in 1971 onboard the Apollo 15 mission to the Moon. In this study, a laser altimeter was proposed as a scientific instrument for the Korean lunar orbiter, which will be launched by 2020, to study the global topography of the surface of the Moon and its gravitational field and to support other payloads such as a terrain mapping camera or spectral imager. This study presents the baseline design and performance model for the proposed laser altimeter. Additionally, the study discusses the expected performance based on numerical simulation results. The simulation results indicate that the design of system parameters satisfies performance requirements with respect to detection probability and range error even under unfavorable conditions.

  5. Design of pulsed laser diode drive power for ZY3(02) laser altimeter

    Science.gov (United States)

    Feng, Wen; Li, Mingshan; Meng, Peibei; Yan, Fanjiang; Li, Xu; Wang, Chunhui

    2017-11-01

    Solid laser pumped by semiconductor laser has the large value in the area of space laser technology, because of the advantages of high efficiency, small volume and long life. As the indispensable component of laser, laser power is also very important. Combined with ZY3(02) laser altimeter project, a high voltage(0-300V), high current(0-80A), long pulse width(0-230us) and high precision temperature semiconductor laser power is developed. IGBT is applied in the driving circuit as the switch to provide a current pulse for LD. The heating or cooling capacity of TEC is controlled by PID compensation circuit quickly adjusts the duty cycle of the UC1637 PWM signal, to realize the high accuracy controlling of LD working temperature. The tests in the external ambient temperature of 5°C, 20°C, 30°C show that the LD current pulse is stable and the stability of LD working temperature up to +/-0.1°C around the set point temperature, which ensure the highly stable operation of DPL.

  6. Airborne laser altimeter measurements of landscape topography

    International Nuclear Information System (INIS)

    Ritchie, J.C.

    1995-01-01

    Measurements of topography can provide a wealth of information on landscape properties for managing hydrologic and geologic systems and conserving natural and agricultural resources. This article discusses the application of an airborne laser altimeter to measure topography and other landscape surface properties. The airborne laser altimeter makes 4000 measurements per second with a vertical recording resolution of 5 cm. Data are collected digitally with a personal computer. A video camera, borehole sighted with the laser, records an image for locating flight lines. GPS data are used to locate flight line positions on the landscape. Laser data were used to measure vegetation canopy topography, height, cover, and distribution and to measure microtopography of the land surface and gullies with depths of 15–20 cm. Macrotopography of landscape profiles for segments up to 4 km were in agreement with available topographic maps but provided more detail. Larger gullies with and without vegetation, and stream channel cross sections and their associated floodplains have also been measured and reported in other publications. Landscape segments for any length could be measured for either micro- or macrotopography. Airborne laser altimeter measurements of landscape profiles can provide detailed information on landscape properties or specific needs that will allow better decisions on the design and location of structures (i.e., roads, pipe, and power lines) and for improving the management and conservation of natural and agricultural landscapes. (author)

  7. Initial development of a laser altimeter

    Science.gov (United States)

    Gilio, J. P.

    1985-09-01

    A design study was carried out of a small, expendable, self-contained laser altimeter for overwater operation at low altitude. A .904 micrometer Gallium Arsenide laser was used to build a prototype transmitter/ receiver at a cost of less than $600 and small enough to fit inside a 5 inch diameter cylinder, 5 inches long. Tests at a height of 120 feet above the surface of a lake resulted in a signal-to-noise ratio of 6, and validated the trade-off equation used in this study. A second test model, with design improvements incorporated, is predicted to yield a SNR of over 20 for an altitude of 150 meters.

  8. The Ganymede Laser Altimeter (GALA)

    Science.gov (United States)

    Hussmann, H.

    2015-12-01

    The Ganymede Laser Altimeter (GALA) is one of the instruments selected for ESA's Jupiter Icy Moons Explorer (JUICE). A fundamental goal of any exploratory space mission is to characterize and measure the shape, topography, and rotation of the target bodies. A state of the art tool for this task is laser altimetry because it can provide absolute topographic height and position with respect to a body centered reference system. With respect to Ganymede, the GALA instrument aims at mapping of global, regional and local topography; confirming the global subsurface ocean and further characterization of the water-ice/liquid shell by monitoring the dynamic response of the ice shell to tidal forces; providing constraints on the forced physical librations and spin-axis obliquity; determining Ganymede's shape; obtaining detailed topographic profiles across the linear features of grooved terrain, impact structures, possible cryo-volcanic features and other different surface units; providing information about slope, roughness and albedo (at 1064nm) of Ganymede's surface. GALA uses the direct-detection (classical) approach of laser altimetry. Laser pulses are emitted at a wavelength of 1064 nm by using an actively Q-switched Nd:Yag laser. The pulse energy and pulse repetition frequency are 17 mJ at 30 Hz, respectively. The emission time of each pulse is measured by the detector. The beam is reflected from the surface and received at a 25 cm diameter F/1 telescope. The returning laser pulse is refocused onto a silicon avalanche photodiode (APD) through back-end optics including a narrow bandpass interference filter for isolating the 1064 nm wavelength. The APD-signal is then amplified, sampled and fed to a digital range finder. The minimum acceptable SNR is approx. 1.2. This system determines the time of flight, pulse intensity, width and full shape. The GALA instrument is developed in collaboration of institutes and industry from Germany, Japan, Switzerland and Spain.

  9. A sample design for globally consistent biomass estimation using lidar data from the Geoscience Laser Altimeter System (GLAS)

    Science.gov (United States)

    Sean P. Healey; Paul L. Patterson; Sassan S. Saatchi; Michael A. Lefsky; Andrew J. Lister; Elizabeth A. Freeman

    2012-01-01

    Lidar height data collected by the Geosciences Laser Altimeter System (GLAS) from 2002 to 2008 has the potential to form the basis of a globally consistent sample-based inventory of forest biomass. GLAS lidar return data were collected globally in spatially discrete full waveform "shots," which have been shown to be strongly correlated with aboveground forest...

  10. The Mercury Laser Altimeter Instrument for the MESSENGER Mission

    Science.gov (United States)

    Cavanaugh, John F.; Smith, James C.; Sun, Xiaoli; Bartels, Arlin E.; Ramos-Izquierdo, Luis; Krebs, Danny J.; Novo-Gradac, Anne marie; McGarry, Jan F.; Trunzo, Raymond; Britt, Jamie L.

    2006-01-01

    The Mercury Laser Altimeter (MLA) is one of the payload science instruments on the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission, which launched on 3 August 2004. The altimeter will measure the round trip time-of-flight of transmitted laser pulses reflected from the surface of the planet that, in combination with the spacecraft orbit position and pointing data, gives a high-precision measurement of surface topography referenced to Mercury's center of mass. The altimeter measurements will be used to determine the planet's forced librations by tracking the motion of large-scale topographic features as a function of time. MLA's laser pulse energy monitor and the echo pulse energy estimate will provide an active measurement of the surface reflectivity at 1064 nm. This paper describes the instrument design, prelaunch testing, calibration, and results of post-launch testing.

  11. Single photon laser altimeter simulator and statistical signal processing

    Science.gov (United States)

    Vacek, Michael; Prochazka, Ivan

    2013-05-01

    Spaceborne altimeters are common instruments onboard the deep space rendezvous spacecrafts. They provide range and topographic measurements critical in spacecraft navigation. Simultaneously, the receiver part may be utilized for Earth-to-satellite link, one way time transfer, and precise optical radiometry. The main advantage of single photon counting approach is the ability of processing signals with very low signal-to-noise ratio eliminating the need of large telescopes and high power laser source. Extremely small, rugged and compact microchip lasers can be employed. The major limiting factor, on the other hand, is the acquisition time needed to gather sufficient volume of data in repetitive measurements in order to process and evaluate the data appropriately. Statistical signal processing is adopted to detect signals with average strength much lower than one photon per measurement. A comprehensive simulator design and range signal processing algorithm are presented to identify a mission specific altimeter configuration. Typical mission scenarios (celestial body surface landing and topographical mapping) are simulated and evaluated. The high interest and promising single photon altimeter applications are low-orbit (˜10 km) and low-radial velocity (several m/s) topographical mapping (asteroids, Phobos and Deimos) and landing altimetry (˜10 km) where range evaluation repetition rates of ˜100 Hz and 0.1 m precision may be achieved. Moon landing and asteroid Itokawa topographical mapping scenario simulations are discussed in more detail.

  12. SPACE-BORNE LASER ALTIMETER GEOLOCATION ERROR ANALYSIS

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2018-05-01

    Full Text Available This paper reviews the development of space-borne laser altimetry technology over the past 40 years. Taking the ICESAT satellite as an example, a rigorous space-borne laser altimeter geolocation model is studied, and an error propagation equation is derived. The influence of the main error sources, such as the platform positioning error, attitude measurement error, pointing angle measurement error and range measurement error, on the geolocation accuracy of the laser spot are analysed by simulated experiments. The reasons for the different influences on geolocation accuracy in different directions are discussed, and to satisfy the accuracy of the laser control point, a design index for each error source is put forward.

  13. Photogrammetry and altimetry. Part A: Apollo 16 laser altimeter

    Science.gov (United States)

    Wollenhaupt, W. R.; Sjogren, W. L.

    1972-01-01

    The laser altimeter measures precise altitudes of the command and service module above the lunar surface and can function either with the metric (mapping) camera or independently. In the camera mode, the laser altimeter ranges at each exposure time, which varies between 20 and 28 sec (i.e., 30 to 43 km on the lunar surface). In the independent mode, the laser altimeter ranges every 20 sec. These altitude data and the spacecraft attitudes that are derived from simultaneous stellar photography are used to constrain the photogrammetric reduction of the lunar surface photographs when cartographic products are generated. In addition, the altimeter measurements alone provide broad-scale topographic relief around the entire circumference of the moon. These data are useful in investigating the selenodetic figure of the moon and may provide information regarding gravitational anomalies on the lunar far side.

  14. Measuring canopy structure with an airborne laser altimeter

    International Nuclear Information System (INIS)

    Ritchie, J.C.; Evans, D.L.; Jacobs, D.; Everitt, J.H.; Weltz, M.A.

    1993-01-01

    Quantification of vegetation patterns and properties is needed to determine their role on the landscape and to develop management plans to conserve our natural resources. Quantifying vegetation patterns from the ground, or by using aerial photography or satellite imagery is difficult, time consuming, and often expensive. Digital data from an airborne laser altimeter offer an alternative method to quantify selected vegetation properties and patterns of forest and range vegetation. Airborne laser data found canopy heights varied from 2 to 6 m within even-aged pine forests. Maximum canopy heights measured with the laser altimeter were significantly correlated to measurements made with ground-based methods. Canopy shape could be used to distinguish deciduous and evergreen trees. In rangeland areas, vegetation heights, spatial patterns, and canopy cover measured with the laser altimeter were significantly related with field measurements. These studies demonstrate the potential of airborne laser data to measure canopy structure and properties for large areas quickly and quantitatively

  15. Straylight analysis of the BepiColombo Laser Altimeter

    Science.gov (United States)

    Weigel, T.; Rugi-Grond, E.; Kudielka, K.

    2008-09-01

    The BepiColombo Laser Altimeter (BELA) shall profile the surface of planet Mercury and operates on the day side as well as on the night side. Because of the high thermal loads, most interior surfaces of the front optics are highly reflective and specular, including the baffle. This puts a handicap on the straylight performance, which is needed to limit the solar background. We present the design measures used to reach an attenuation of about 10-8. We resume the method of backward straylight analysis which starts the rays at the detector and analyses the results in object space. The backward analysis can be quickly compiled and challenges computer resources rather than labor effort. This is very useful in a conceptual design phase when a design is iterated and trade-offs are to be performed. For one design, we compare the results with values obtained from a forward analysis.

  16. Test Port for Fiber-Optic-Coupled Laser Altimeter

    Science.gov (United States)

    Ramos Izquierdo, Luis; Scott, V. Stanley; Rinis, Haris; Cavanaugh, John

    2011-01-01

    A test port designed as part of a fiber optic coupled laser altimeter receiver optical system allows for the back-illumination of the optical system for alignment verification, as well as illumination of the detector(s) for testing the receiver electronics and signal-processing algorithms. Measuring the optical alignment of a laser altimeter instrument is difficult after the instrument is fully assembled. The addition of a test port in the receiver aft-optics allows for the back-illumination of the receiver system such that its focal setting and boresight alignment can be easily verified. For a multiple-detector receiver system, the addition of the aft-optics test port offers the added advantage of being able to simultaneously test all the detectors with different signals that simulate the expected operational conditions. On a laser altimeter instrument (see figure), the aft-optics couple the light from the receiver telescope to the receiver detector(s). Incorporating a beam splitter in the aft-optics design allows for the addition of a test port to back-illuminate the receiver telescope and/or detectors. The aft-optics layout resembles a T with the detector on one leg, the receiver telescope input port on the second leg, and the test port on the third leg. The use of a custom beam splitter with 99-percent reflection, 1-percent transmission, and a mirrored roof can send the test port light to the receiver telescope leg as well as the detector leg, without unduly sacrificing the signal from the receiver telescope to the detector. The ability to test the receiver system alignment, as well as multiple detectors with different signals without the need to disassemble the instrument or connect and reconnect components, is a great advantage to the aft-optics test port. Another benefit is that the receiver telescope aperture is fully back-illuminated by the test port so the receiver telescope focal setting vs. pressure and or temperature can be accurately measured (as

  17. IceBridge Riegl Laser Altimeter L1B Time-Tagged Laser Ranges

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge Riegl Laser Altimeter L1B Time-Tagged Laser Ranges (ILUTP1B) data set contains laser ranges, returned pulses, and deviation for returned pulses in...

  18. Laser altimeter measurements at Walnut Gulch Watershed, Arizona

    International Nuclear Information System (INIS)

    Ritchie, J.C.; Humes, K.S.; Weltz, M.A.

    1995-01-01

    Measurements of landscape surface roughness properties are necessary for understanding many watershed processes. This paper reviews the use of an airborne laser altimeter to measure topography and surface roughness properties of the landscape at Walnut Gulch Watershed in Arizona. Airborne laser data were used to measure macro and micro topography as well as canopy topography, height, cover, and distribution. Macro topography of landscape profiles for segments up to 5 km (3 mi) were measured and were in agreement with available topographic maps but provided more detail. Gullies and stream channel cross-sections and their associated floodplains were measured. Laser measurements of vegetation properties (height and cover) were highly correlated with ground measurements. Landscape segments for any length can be used to measure these landscape roughness properties. Airborne laser altimeter measurements of landscape profiles can provide detailed information on watershed surface properties for improving the management of watersheds. (author)

  19. An overview of the laser ranging method of space laser altimeter

    Science.gov (United States)

    Zhou, Hui; Chen, Yuwei; Hyyppä, Juha; Li, Song

    2017-11-01

    Space laser altimeter is an active remote sensing instrument to measure topographic map of Earth, Moon and planetary. The space laser altimeter determines the range between the instrument and laser footprint by measuring round trip time of laser pulse. The return pulse reflected from ground surface is gathered by the receiver of space laser altimeter, the pulsewidth and amplitude of which are changeable with the variability of the ground relief. Meantime, several kinds of noise overlapped on the return pulse signal affect its signal-to-noise ratio. To eliminate the influence of these factors that cause range walk and range uncertainty, the reliable laser ranging methods need to be implemented to obtain high-precision range results. Based on typical space laser altimeters in the past few decades, various ranging methods are expounded in detail according to the operational principle of instruments and timing method. By illustrating the concrete procedure of determining time of flight of laser pulse, this overview provides the comparison of the employed technologies in previous and undergoing research programs and prospect innovative technology for space laser altimeters in future.

  20. Measurement and stability of the pointing of the BepiColombo Laser Altimeter under thermal load

    Science.gov (United States)

    Gouman, J.; Beck, T.; Affolter, M.; Thomas, N.; Geissbühler, U.; Péteut, A.; Bandy, T.; Servonet, A.; Piazza, D.; Seiferlin, K.

    2014-04-01

    The first European laser altimeter, designed for interplanetary flight, BELA, (on BepiColombo mission to Mercury) will be launched in July 2016. This abstract describes the setup used to characterize the angular movements of BELA during the simulation of the environment that the instrument will encounter when orbiting Mercury. Tests performed using the Engineering Qualification Model (EQM) show that the setup is accurate enough to characterize angular movements of the instrument components with an accuracy of ≈ 10 μrad.

  1. Laser altimeter observations from MESSENGER's first Mercury flyby.

    Science.gov (United States)

    Zuber, Maria T; Smith, David E; Solomon, Sean C; Phillips, Roger J; Peale, Stanton J; Head, James W; Hauck, Steven A; McNutt, Ralph L; Oberst, Jürgen; Neumann, Gregory A; Lemoine, Frank G; Sun, Xiaoli; Barnouin-Jha, Olivier; Harmon, John K

    2008-07-04

    A 3200-kilometers-long profile of Mercury by the Mercury Laser Altimeter on the MESSENGER spacecraft spans approximately 20% of the near-equatorial region of the planet. Topography along the profile is characterized by a 5.2-kilometer dynamic range and 930-meter root-mean-square roughness. At long wavelengths, topography slopes eastward by 0.02 degrees , implying a variation of equatorial shape that is at least partially compensated. Sampled craters on Mercury are shallower than their counterparts on the Moon, at least in part the result of Mercury's higher gravity. Crater floors vary in roughness and slope, implying complex modification over a range of length scales.

  2. The OSIRIS-REx Laser Altimeter (OLA) Investigation and Instrument

    Science.gov (United States)

    Daly, M. G.; Barnouin, O. S.; Dickinson, C.; Seabrook, J.; Johnson, C. L.; Cunningham, G.; Haltigin, T.; Gaudreau, D.; Brunet, C.; Aslam, I.; Taylor, A.; Bierhaus, E. B.; Boynton, W.; Nolan, M.; Lauretta, D. S.

    2017-10-01

    The Canadian Space Agency (CSA) has contributed to the Origins Spectral Interpretation Resource Identification Security-Regolith Explorer (OSIRIS-REx) spacecraft the OSIRIS-REx Laser Altimeter (OLA). The OSIRIS-REx mission will sample asteroid 101955 Bennu, the first B-type asteroid to be visited by a spacecraft. Bennu is thought to be primitive, carbonaceous, and spectrally most closely related to CI and/or CM meteorites. As a scanning laser altimeter, the OLA instrument will measure the range between the OSIRIS-REx spacecraft and the surface of Bennu to produce digital terrain maps of unprecedented spatial scales for a planetary mission. The digital terrain maps produced will measure ˜7 cm per pixel globally, and ˜3 cm per pixel at specific sample sites. In addition, OLA data will be used to constrain and refine the spacecraft trajectories. Global maps and highly accurate spacecraft trajectory estimates are critical to infer the internal structure of the asteroid. The global and regional maps also are key to gain new insights into the surface processes acting across Bennu, which inform the selection of the OSIRIS-REx sample site. These, in turn, are essential for understanding the provenance of the regolith sample collected by the OSIRIS-REx spacecraft. The OLA data also are important for quantifying any hazards near the selected OSIRIS-REx sample site and for evaluating the range of tilts at the sampling site for comparison against the capabilities of the sample acquisition device.

  3. ZY3-02 Laser Altimeter On-orbit Geometrical Calibration and Test

    Directory of Open Access Journals (Sweden)

    TANG Xinming

    2017-06-01

    Full Text Available ZY3-02 is the first satellite equipped with a laser altimeter for earth observation in China .This laser altimeter is an experimental payload for land elevation measurement experiment. The ranging and pointing bias of the laser altimeter would change due to the launch vibration, the space environment difference or other factors, and that could bring plane and elevation errors of laser altimeter. In this paper, we propose an on-orbit geometric calibration method using a ground-based electro-optical detection system based on the analysis of ZY3-02 laser altimeter characteristic, and this method constructs the rigorous geometric calibration model, which consider the pointing and ranging bias as unknown systematic errors, and the unknown parameters are calibrated with laser spot's location captured by laser detectors and the minimum ranging error principle. With the ALOS-DSM data as reference, the elevation accuracy of the laser altimeter can be improved from 100~150 meters before calibration to 2~3 meters after calibration when the terrain slope is less than 2 degree. With several ground control points obtained with RTK in laser footprint for validation, the absolute elevation precision of laser altimeter in the flat area can reach about 1 meter after the calibration. The test results demonstrated the effectiveness and feasibility of the proposed method.

  4. Revised coordinates of the Mars Orbiter Laser Altimeter (MOLA) footprints

    Science.gov (United States)

    Annibali, S.; Stark, A.; Gwinner, K.; Hussmann, H.; Oberst, J.

    2017-09-01

    We revised the Mars Orbiter Laser Altimeter (MOLA) footprint locations (i.e. areocentric body-fixed latitude and longitude), using updated trajectory models for the Mars Global Surveyor and updated rotation parameters of Mars, including precession, nutation and length-of-day variation. We assess the impact of these updates on the gridded MOLA maps. A first comparison reveals that even slight corrections to the rotational state of Mars can lead to height differences up to 100 m (in particular in regions with high slopes, where large interpolation effects are expected). Ultimately, we aim at independent measurements of the rotation parameters of Mars. We co-register MOLA profiles to digital terrain models from stereo images (stereo DTMs) and measure offsets of the two data sets.

  5. Lunar Topography: Results from the Lunar Orbiter Laser Altimeter

    Science.gov (United States)

    Neumann, Gregory; Smith, David E.; Zuber, Maria T.; Mazarico, Erwan

    2012-01-01

    The Lunar Orbiter Laser Altimeter (LOLA) onboard the Lunar Reconnaissance Orbiter (LRO) has been operating nearly continuously since July 2009, accumulating over 6 billion measurements from more than 2 billion in-orbit laser shots. LRO's near-polar orbit results in very high data density in the immediate vicinity of the lunar poles, with full coverage at the equator from more than 12000 orbital tracks averaging less than 1 km in spacing at the equator. LRO has obtained a global geodetic model of the lunar topography with 50-meter horizontal and 1-m radial accuracy in a lunar center-of-mass coordinate system, with profiles of topography at 20-m horizontal resolution, and 0.1-m vertical precision. LOLA also provides measurements of reflectivity and surface roughness down to its 5-m laser spot size. With these data LOLA has measured the shape of all lunar craters 20 km and larger. In the proposed extended mission commencing late in 2012, LOLA will concentrate observations in the Southern Hemisphere, improving the density of the polar coverage to nearly 10-m pixel resolution and accuracy to better than 20 m total position error. Uses for these data include mission planning and targeting, illumination studies, geodetic control of images, as well as lunar geology and geophysics. Further improvements in geodetic accuracy are anticipated from the use of re ned gravity fields after the successful completion of the Gravity Recovery and Interior Laboratory (GRAIL) mission in 2012.

  6. IceBridge Riegl Laser Altimeter L2 Geolocated Surface Elevation Triplets

    Data.gov (United States)

    National Aeronautics and Space Administration — The IceBridge Riegl Laser Altimeter L2 Geolocated Surface Elevation Triplets (ILUTP2) data set contains surface range values for Antarctica and Greenland derived...

  7. Revised method for forest canopy height estimation from Geoscience Laser Altimeter System waveforms.

    Science.gov (United States)

    Michael A. Lefskya; Michael Keller; Yong Panga; Plinio B. de Camargod; Maria O. Hunter

    2007-01-01

    The vertical extent of waveforms collected by the Geoscience Laser Altimeter System (onboard ICESat - the Ice, Cloud, and land Elevation Satellite) increases as a function of terrain slope and footprint size (the area on the ground that is illuminated by the laser). Over sloped terrain, returns from both canopy and ground surfaces can occur at the same elevation. As a...

  8. On retrieving sea ice freeboard from ICESat laser altimeter

    Directory of Open Access Journals (Sweden)

    K. Khvorostovsky

    2016-10-01

    Full Text Available Sea ice freeboard derived from satellite altimetry is the basis for the estimation of sea ice thickness using the assumption of hydrostatic equilibrium. High accuracy of altimeter measurements and freeboard retrieval procedure are, therefore, required. As of today, two approaches for estimating the freeboard using laser altimeter measurements from Ice, Cloud, and land Elevation Satellite (ICESat, referred to as tie points (TP and lowest-level elevation (LLE methods, have been developed and applied in different studies. We reproduced these methods for the ICESat observation periods (2003–2008 in order to assess and analyse the sources of differences found in the retrieved freeboard and corresponding thickness estimates of the Arctic sea ice as produced by the Jet Propulsion Laboratory (JPL and Goddard Space Flight Center (GSFC. Three main factors are found to affect the freeboard differences when applying these methods: (a the approach used for calculation of the local sea surface references in leads (TP or LLE methods, (b the along-track averaging scales used for this calculation, and (c the corrections for lead width relative to the ICESat footprint and for snow depth accumulated in refrozen leads. The LLE method with 100 km averaging scale, as used to produce the GSFC data set, and the LLE method with a shorter averaging scale of 25 km both give larger freeboard estimates comparing to those derived by applying the TP method with 25 km averaging scale as used for the JPL product. Two factors, (a and (b, contribute to the freeboard differences in approximately equal proportions, and their combined effect is, on average, about 6–7 cm. The effect of using different methods varies spatially: the LLE method tends to give lower freeboards (by up to 15 cm over the thick multiyear ice and higher freeboards (by up to 10 cm over first-year ice and the thin part of multiyear ice; the higher freeboards dominate. We show that the

  9. The Fiber Optic System for the Advanced Topographic Laser Altimeter System (ATLAS) Instrument

    Science.gov (United States)

    Ott, Melanie N.; Thomes, Joe; Onuma, Eleanya; Switzer, Robert; Chuska, Richard; Blair, Diana; Frese, Erich; Matyseck, Marc

    2016-01-01

    The Advanced Topographic Laser Altimeter System (ATLAS) Instrument has been in integration and testing over the past 18 months in preparation for the Ice, Cloud and Land Elevation Satellite - 2 (ICESat-2) Mission, scheduled to launch in 2017. ICESat-2 is the follow on to ICESat which launched in 2003 and operated until 2009. ATLAS will measure the elevation of ice sheets, glaciers and sea ice or the "cryosphere" (as well as terrain) to provide data for assessing the earth's global climate changes. Where ICESat's instrument, the Geo-Science Laser Altimeter (GLAS) used a single beam measured with a 70 m spot on the ground and a distance between spots of 170 m, ATLAS will measure a spot size of 10 m with a spacing of 70 cm using six beams to measure terrain height changes as small as 4 mm. The ATLAS pulsed transmission system consists of two lasers operating at 532 nm with transmitter optics for beam steering, a diffractive optical element that splits the signal into 6 separate beams, receivers for start pulse detection and a wavelength tracking system. The optical receiver telescope system consists of optics that focus all six beams into optical fibers that feed a filter system that transmits the signal via fiber assemblies to the detectors. Also included on the instrument is a system that calibrates the alignment of the transmitted pulses to the receiver optics for precise signal capture. The larger electro optical subsystems for transmission, calibration, and signal receive, stay aligned and transmitting sufficiently due to the optical fiber system that links them together. The robust design of the fiber optic system, consisting of a variety of multi fiber arrays and simplex assemblies with multiple fiber core sizes and types, will enable the system to maintain consistent critical alignments for the entire life of the mission. Some of the development approaches used to meet the challenging optical system requirements for ATLAS are discussed here.

  10. The fiber optic system for the Advanced Topographic Laser Altimeter System (ATLAS) instrument.

    Science.gov (United States)

    Ott, Melanie N; Thomes, Joe; Onuma, Eleanya; Switzer, Robert; Chuska, Richard; Blair, Diana; Frese, Erich; Matyseck, Marc

    2016-08-28

    The Advanced Topographic Laser Altimeter System (ATLAS) Instrument has been in integration and testing over the past 18 months in preparation for the Ice, Cloud and Land Elevation Satellite - 2 (ICESat-2) Mission, scheduled to launch in 2017. ICESat-2 is the follow on to ICESat which launched in 2003 and operated until 2009. ATLAS will measure the elevation of ice sheets, glaciers and sea ice or the "cryosphere" (as well as terrain) to provide data for assessing the earth's global climate changes. Where ICESat's instrument, the Geo-Science Laser Altimeter (GLAS) used a single beam measured with a 70 m spot on the ground and a distance between spots of 170 m, ATLAS will measure a spot size of 10 m with a spacing of 70 cm using six beams to measure terrain height changes as small as 4 mm.[1] The ATLAS pulsed transmission system consists of two lasers operating at 532 nm with transmitter optics for beam steering, a diffractive optical element that splits the signal into 6 separate beams, receivers for start pulse detection and a wavelength tracking system. The optical receiver telescope system consists of optics that focus all six beams into optical fibers that feed a filter system that transmits the signal via fiber assemblies to the detectors. Also included on the instrument is a system that calibrates the alignment of the transmitted pulses to the receiver optics for precise signal capture. The larger electro optical subsystems for transmission, calibration, and signal receive, stay aligned and transmitting sufficiently due to the optical fiber system that links them together. The robust design of the fiber optic system, consisting of a variety of multi fiber arrays and simplex assemblies with multiple fiber core sizes and types, will enable the system to maintain consistent critical alignments for the entire life of the mission. Some of the development approaches used to meet the challenging optical system requirements for ATLAS are discussed here.

  11. The OSIRIS-REx laser altimeter (OLA): Development progress

    Science.gov (United States)

    Daly, M.; Barnouin, O.; Johnson, C.; Bierhaus, E.; Seabrook, J.; Dickinson, C.; Haltigin, T.; Gaudreau, D.; Brunet, C.; Cunningham, G.; Lauretta, D.; Boynton, W.; Beshore, E.

    2014-07-01

    Introduction: The NASA New Frontiers Origins Spectral Interpretation Resource Identification Security Regolith Explorer (OSIRIS-REx) mission will be the first to sample the B-type asteroid (101955) Bennu [1]. This asteroid is thought to be primitive and carbonaceous, and is probably closely related to CI and/or CM meteorites [2]. The OSIRIS-REx mission hopes to better understand both the physical and geochemical origin and evolution of carbonaceous asteroids through its investigation of Bennu. The OSIRIS-REx spacecraft will launch in September 2016, and arrive at Bennu two years later. The Canadian Space Agency is contributing a scanning lidar system known as the OSIRIS-REx Laser Altimeter (OLA), to the OSIRIS-REx Mission. The OLA instrument is part of suite of onboard instruments [3] including cameras (OCAMS) [4], a visible and near- infrared spectrometer (OVIRS) [5], a thermal emission spectrometer (OTES), and an X-ray imaging spectrometer (REXIS) [6]. OLA Objectives: The OLA instrument has a suite of scientific and mission operations purposes. At a global scale, it will update the shape and mass of Bennu to provide insights on the geological origin and evolution of Bennu, by, for example, further refining constraints on its bulk density. With a carefully undertaken geodesy campaign, OLA-based precision ranges, constraints from radio science (2-way tracking) data and stereo OCAMS images, it will yield broad-scale, quantitative constraints on any internal heterogeneity of Bennu and hence provide further clues to Bennu's origin and subsequent collisional evolution. OLA-derived global asteroid maps of slopes, elevation relative to the asteroid geoid, and vertical roughness will provide quantitative insights on how local-regional surfaces on Bennu evolved subsequent to the formation of the asteroid. In addition, OLA data and derived products support the assessment of the safety and sampleability of potential sample sites. At the sample-site scale, the OLA instrument

  12. Light Detection and Ranging (LIDAR) From Space - Laser Altimeters

    Science.gov (United States)

    Sun, Xiaoli

    2016-01-01

    Light detection and ranging, or lidar, is like radar but atoptical wavelengths. The principle of operation and theirapplications in remote sensing are similar. Lidars havemany advantages over radars in instrument designs andapplications because of the much shorter laser wavelengthsand narrower beams. The lidar transmitters and receiveroptics are much smaller than radar antenna dishes. Thespatial resolution of lidar measurement is much finer thanthat of radar because of the much smaller footprint size onground. Lidar measurements usually give a better temporalresolution because the laser pulses can be much narrowerthan radio frequency (RF) signals. The major limitation oflidar is the ability to penetrate clouds and ground surfaces.

  13. The Topography of Mars: Understanding the Surface of Mars Through the Mars Orbiter Laser Altimeter

    Science.gov (United States)

    Derby, C. A.; Neumann, G. A.; Sakimoto, S. E.

    2001-12-01

    The Mars Orbiter Laser Altimeter has been orbiting Mars since 1997 and has measured the topography of Mars with a meter of vertical accuracy. This new information has improved our understanding of both the surface and the interior of Mars. The topographic globe and the labeled topographic map of Mars illustrate these new data in a format that can be used in a classroom setting. The map is color shaded to show differences in elevation on Mars, presenting Mars with a different perspective than traditional geological and geographic maps. Through the differences in color, students can see Mars as a three-dimensional surface and will be able to recognize features that are invisible in imagery. The accompanying lesson plans are designed for middle school science students and can be used both to teach information about Mars as a planet and Mars in comparison to Earth, fitting both the solar system unit and the Earth science unit in a middle school curriculum. The lessons are referenced to the National Benchmark standards for students in grades 6-8 and cover topics such as Mars exploration, the Mars Orbiter Laser Altimeter, resolution and powers of 10, gravity, craters, seismic waves and the interior structure of a planet, isostasy, and volcanoes. Each lesson is written in the 5 E format and includes a student content activity and an extension showing current applications of Mars and MOLA data. These activities can be found at http://ltpwww.gsfc.nasa.gov/education/resources.html. Funding for this project was provided by the Maryland Space Grant Consortium and the MOLA Science Team, Goddard Space Flight Center.

  14. Improving maps of ice-sheet surface elevation change using combined laser altimeter and stereoscopic elevation model data

    DEFF Research Database (Denmark)

    Fredenslund Levinsen, Joanna; Howat, I. M.; Tscherning, C. C.

    2013-01-01

    We combine the complementary characteristics of laser altimeter data and stereoscopic digital elevation models (DEMs) to construct high-resolution (_100 m) maps of surface elevations and elevation changes over rapidly changing outlet glaciers in Greenland. Measurements from spaceborne and airborne...... laser altimeters have relatively low errors but are spatially limited to the ground tracks, while DEMs have larger errors but provide spatially continuous surfaces. The principle of our method is to fit the DEM surface to the altimeter point clouds in time and space to minimize the DEM errors and use...... that surface to extrapolate elevations away from altimeter flight lines. This reduces the DEM registration errors and fills the gap between the altimeter paths. We use data from ICESat and ATM as well as SPOT 5 DEMs from 2007 and 2008 and apply them to the outlet glaciers Jakobshavn Isbræ (JI...

  15. Measurements of land surface features using an airborne laser altimeter: the HAPEX-Sahel experiment

    International Nuclear Information System (INIS)

    Ritchie, J.C.; Menenti, M.; Weltz, M.A.

    1997-01-01

    An airborne laser profiling altimeter was used to measure surface features and properties of the landscape during the HAPEX-Sahel Experiment in Niger, Africa in September 1992. The laser altimeter makes 4000 measurements per second with a vertical resolution of 5 cm. Airborne laser and detailed field measurements of vegetation heights had similar average heights and frequency distribution. Laser transects were used to estimate land surface topography, gully and channel morphology, and vegetation properties ( height, cover and distribution). Land surface changes related to soil erosion and channel development were measured. For 1 km laser transects over tiger bush communities, the maximum vegetation height was between 4-5 and 6-5 m, with an average height of 21 m. Distances between the centre of rows of tiger bush vegetation averaged 100 m. For two laser transects, ground cover for tiger bush was estimated to be 225 and 301 per cent for vegetation greater than 0-5m tall and 190 and 25-8 per cent for vegetation greater than 10m tall. These values are similar to published values for tiger bush. Vegetation cover for 14 and 18 km transects was estimated to be 4 per cent for vegetation greater than 0-5 m tall. These cover values agree within 1-2 per cent with published data for short transects (⩾ 100 m) for the area. The laser altimeter provided quick and accurate measurements for evaluating changes in land surface features. Such information provides a basis for understanding land degradation and a basis for management plans to rehabilitate the landscape. (author)

  16. Night and Day: The Opacity of Clouds Measured by the Mars Orbiter Laser Altimeter (MOLA)

    Science.gov (United States)

    Neumann, G. A.; Wilson, R. J.

    2006-01-01

    The Mars Orbiter Laser Altimeter (MOLA) [l] on the Mars Global Surveyor spacecraft ranged to clouds over the course of nearly two Mars years [2] using an active laser ranging system. While ranging to the surface, the instrument was also able to measure the product of the surface reflectivity with the two-way atmospheric transmission at 1064 nm. Furthermore, the reflectivity has now been mapped over seasonal cycles using the passive radiometric capability built into MOLA [3]. Combining these measurements, the column opacity may be inferred. MOLA uniquely provides these measurements both night and day. This study examines the pronounced nighttime opacity of the aphelion season tropical water ice clouds, and the indiscernibly low opacity of the southern polar winter clouds. The water ice clouds (Figure 1) do not themselves trigger the altimeter but have measured opacities tau > 1.5 and are temporally and spatially correlated with temperature anomalies predicted by a Mars Global Circulation Model (MGCM) that incorporates cloud radiative effects [4]. The south polar CO2 ice clouds trigger the altimeter with a very high backscatter cross-section over a thickness of 3-9 m and are vertically dispersed over several km, but their total column opacities lie well below the MOLA measurement limit of tau = 0.7. These clouds correspond to regions of supercooled atmosphere that may form either very large specularly reflecting particles [2] or very compact, dense concentrations (>5x10(exp 6)/cu m) of 100-p particles

  17. Summary of the results from the lunar orbiter laser altimeter after seven years in lunar orbit

    Science.gov (United States)

    Smith, David E.; Zuber, Maria T.; Neumann, Gregory A.; Mazarico, Erwan; Lemoine, Frank G.; Head, James W., III; Lucey, Paul G.; Aharonson, Oded; Robinson, Mark S.; Sun, Xiaoli; Torrence, Mark H.; Barker, Michael K.; Oberst, Juergen; Duxbury, Thomas C.; Mao, Dandan; Barnouin, Olivier S.; Jha, Kopal; Rowlands, David D.; Goossens, Sander; Baker, David; Bauer, Sven; Gläser, Philipp; Lemelin, Myriam; Rosenburg, Margaret; Sori, Michael M.; Whitten, Jennifer; Mcclanahan, Timothy

    2017-02-01

    In June 2009 the Lunar Reconnaissance Orbiter (LRO) spacecraft was launched to the Moon. The payload consists of 7 science instruments selected to characterize sites for future robotic and human missions. Among them, the Lunar Orbiter Laser Altimeter (LOLA) was designed to obtain altimetry, surface roughness, and reflectance measurements. The primary phase of lunar exploration lasted one year, following a 3-month commissioning phase. On completion of its exploration objectives, the LRO mission transitioned to a science mission. After 7 years in lunar orbit, the LOLA instrument continues to map the lunar surface. The LOLA dataset is one of the foundational datasets acquired by the various LRO instruments. LOLA provided a high-accuracy global geodetic reference frame to which past, present and future lunar observations can be referenced. It also obtained high-resolution and accurate global topography that were used to determine regions in permanent shadow at the lunar poles. LOLA further contributed to the study of polar volatiles through its unique measurement of surface brightness at zero phase, which revealed anomalies in several polar craters that may indicate the presence of water ice. In this paper, we describe the many LOLA accomplishments to date and its contribution to lunar and planetary science.

  18. Summary of the Results from the Lunar Orbiter Laser Altimeter after Seven Years in Lunar Orbit

    Science.gov (United States)

    Smith, David E.; Zuber, Maria T.; Neumann, Gregory A.; Mazarico, Erwan; Lemoine, Frank G.; Head, James W., III; Lucey, Paul G.; Aharonson, Oded; Robinson, Mark S.; Sun, Xiaoli; hide

    2016-01-01

    In June 2009 the Lunar Reconnaissance Orbiter (LRO) spacecraft was launched to the Moon. The payload consists of 7 science instruments selected to characterize sites for future robotic and human missions. Among them, the Lunar Orbiter Laser Altimeter (LOLA) was designed to obtain altimetry, surface roughness, and reflectance measurements. The primary phase of lunar exploration lasted one year, following a 3-month commissioning phase. On completion of its exploration objectives, the LRO mission transitioned to a science mission. After 7 years in lunar orbit, the LOLA instrument continues to map the lunar surface. The LOLA dataset is one of the foundational datasets acquired by the various LRO instruments. LOLA provided a high-accuracy global geodetic reference frame to which past, present and future lunar observations can be referenced. It also obtained high-resolution and accurate global topography that were used to determine regions in permanent shadow at the lunar poles. LOLA further contributed to the study of polar volatiles through its unique measurement of surface brightness at zero phase, which revealed anomalies in several polar craters that may indicate the presence of water ice. In this paper, we describe the many LOLA accomplishments to date and its contribution to lunar and planetary science.

  19. Polarimetric, Two-Color, Photon-Counting Laser Altimeter Measurements of Forest Canopy Structure

    Science.gov (United States)

    Harding, David J.; Dabney, Philip W.; Valett, Susan

    2011-01-01

    Laser altimeter measurements of forest stands with distinct structures and compositions have been acquired at 532 nm (green) and 1064 nm (near-infrared) wavelengths and parallel and perpendicular polarization states using the Slope Imaging Multi-polarization Photon Counting Lidar (SIMPL). The micropulse, single photon ranging measurement approach employed by SIMPL provides canopy structure measurements with high vertical and spatial resolution. Using a height distribution analysis method adapted from conventional, 1064 nm, full-waveform lidar remote sensing, the sensitivity of two parameters commonly used for above-ground biomass estimation are compared as a function of wavelength. The results for the height of median energy (HOME) and canopy cover are for the most part very similar, indicating biomass estimations using lidars operating at green and near-infrared wavelengths will yield comparable estimates. The expected detection of increasing depolarization with depth into the canopies due to volume multiple-scattering was not observed, possibly due to the small laser footprint and the small detector field of view used in the SIMPL instrument. The results of this work provide pathfinder information for NASA's ICESat-2 mission that will employ a 532 nm, micropulse, photon counting laser altimeter.

  20. Brightening and Volatile Distribution Within Shackleton Crater Observed by the LRO Laser Altimeter.

    Science.gov (United States)

    Smith, D. E.; Zuber, M. T.; Head, J. W.; Neumann, G. A.; Mazarico, E.; Torrence, M. H.; Aharonson, O.; Tye, A. R.; Fassett, C. I.; Rosengurg, M. A.; hide

    2012-01-01

    Shackleton crater, whose interior lies largely in permanent shadow, is of interest due to its potential to sequester volatiles. Observations from the Lunar Orbiter Laser Altimeter onboard the Lunar Reconnaissance Orbiter have enabled an unprecedented topographic characterization, revealing Shackleton to be an ancient, unusually well-preserved simple crater whose interior walls are fresher than its floor and rim. Shackleton floor deposits are nearly the same age as the rim, suggesting little floor deposition since crater formation over 3 billion years ago. At 1064 nm the floor of Shackleton is brighter than the surrounding terrain and the interiors of nearby craters, but not as bright as the interior walls. The combined observations are explainable primarily by downslope movement of regolith on the walls exposing fresher underlying material. The relatively brighter crater floor is most simply explained by decreased space weathering due to shadowing, but a 1-mm-thick layer containing approx 20% surficial ice is an alternative possibility.

  1. Thermal Testing and Model Correlation for Advanced Topographic Laser Altimeter Instrument (ATLAS)

    Science.gov (United States)

    Patel, Deepak

    2016-01-01

    The Advanced Topographic Laser Altimeter System (ATLAS) part of the Ice Cloud and Land Elevation Satellite 2 (ICESat-2) is an upcoming Earth Science mission focusing on the effects of climate change. The flight instrument passed all environmental testing at GSFC (Goddard Space Flight Center) and is now ready to be shipped to the spacecraft vendor for integration and testing. This topic covers the analysis leading up to the test setup for ATLAS thermal testing as well as model correlation to flight predictions. Test setup analysis section will include areas where ATLAS could not meet flight like conditions and what were the limitations. Model correlation section will walk through changes that had to be made to the thermal model in order to match test results. The correlated model will then be integrated with spacecraft model for on-orbit predictions.

  2. Detection of the lunar body tide by the Lunar Orbiter Laser Altimeter.

    Science.gov (United States)

    Mazarico, Erwan; Barker, Michael K; Neumann, Gregory A; Zuber, Maria T; Smith, David E

    2014-04-16

    The Lunar Orbiter Laser Altimeter instrument onboard the Lunar Reconnaissance Orbiter spacecraft collected more than 5 billion measurements in the nominal 50 km orbit over ∼10,000 orbits. The data precision, geodetic accuracy, and spatial distribution enable two-dimensional crossovers to be used to infer relative radial position corrections between tracks to better than ∼1 m. We use nearly 500,000 altimetric crossovers to separate remaining high-frequency spacecraft trajectory errors from the periodic radial surface tidal deformation. The unusual sampling of the lunar body tide from polar lunar orbit limits the size of the typical differential signal expected at ground track intersections to ∼10 cm. Nevertheless, we reliably detect the topographic tidal signal and estimate the associated Love number h 2 to be 0.0371 ± 0.0033, which is consistent with but lower than recent results from lunar laser ranging. Altimetric data are used to create radial constraints on the tidal deformationThe body tide amplitude is estimated from the crossover dataThe estimated Love number is consistent with previous estimates but more precise.

  3. VERTICAL ACCURACY ASSESSMENT OF ZY-3 DIGITAL SURFACE MODEL USING ICESAT/GLAS LASER ALTIMETER DATA

    Directory of Open Access Journals (Sweden)

    G. Li

    2017-05-01

    Full Text Available The Ziyuan-3 (ZY-3 satellite, as the first civilian high resolution surveying and mapping satellite in China, has a very important role in national 1 : 50,000 stereo mapping project. High accuracy digital surface Model (DSMs can be generated from the three line-array images of ZY-3, and ZY-3 DSMs of China can be produced without using any ground control points (GCPs by selecting SRTM (Shuttle Radar Topography Mission and ICESat/GLAS (Ice, Cloud, and land Elevation Satellite, Geo-science Laser Altimeter System as the datum reference in the Satellite Surveying and Mapping Application Center, which is the key institute that manages and distributes ZY-3 products. To conduct the vertical accuracy evaluation of ZY-3 DSMs of China, three representative regions were chosen and the results were compared to ICESat/GLAS data. The experimental results demonstrated that the root mean square error (RMSE elevation accuracy of the ZY-3 DSMs was better than 5.0 m, and it even reached to less than 2.5 m in the second region of eastern China. While this work presents preliminary results, it is an important reference for expanding the application of ZY-3 satellite imagery to widespread regions. And the satellite laser altimetry data can be used as referenced data for wide-area DSM evaluation.

  4. Component-Level Selection and Qualification for the Global Ecosystem Dynamics Investigation (GEDI) Laser Altimeter Transmitter

    Science.gov (United States)

    Frese, Erich A.; Chiragh, Furqan L.; Switzer, Robert; Vasilyev, Aleksey A.; Thomes, Joe; Coyle, D. Barry; Stysley, Paul R.

    2018-01-01

    Flight quality solid-state lasers require a unique and extensive set of testing and qualification processes, both at the system and component levels to insure the laser's promised performance. As important as the overall laser transmitter design is, the quality and performance of individual subassemblies, optics, and electro-optics dictate the final laser unit's quality. The Global Ecosystem Dynamics Investigation (GEDI) laser transmitters employ all the usual components typical for a diode-pumped, solid-state laser, yet must each go through their own individual process of specification, modeling, performance demonstration, inspection, and destructive testing. These qualification processes and results for the laser crystals, laser diode arrays, electro-optics, and optics, will be reviewed as well as the relevant critical issues encountered, prior to their installation in the GEDI flight laser units.

  5. The Lunar Orbiter Laser Altimeter (LOLA) on NASA's Lunar Reconnaissance Orbiter (LRO) mission

    Science.gov (United States)

    Riris, H.; Cavanaugh, J.; Sun, X.; Liiva, P.; Rodriguez, M.; Neuman, G.

    2017-11-01

    The Lunar Orbiter Laser Altimeter (LOLA) instrument [1-3] on NASA's Lunar Reconnaissance Orbiter (LRO) mission, launched on June 18th, 2009, from Kennedy Space Center, Florida, will provide a precise global lunar topographic map using laser altimetry. LOLA will assist in the selection of landing sites on the Moon for future robotic and human exploration missions and will attempt to detect the presence of water ice on or near the surface, which is one of the objectives of NASA's Exploration Program. Our present knowledge of the topography of the Moon is inadequate for determining safe landing areas for NASA's future lunar exploration missions. Only those locations, surveyed by the Apollo missions, are known with enough detail. Knowledge of the position and characteristics of the topographic features on the scale of a lunar lander are crucial for selecting safe landing sites. Our present knowledge of the rest of the lunar surface is at approximately 1 km kilometer level and in many areas, such as the lunar far side, is on the order of many kilometers. LOLA aims to rectify that and provide a precise map of the lunar surface on both the far and near side of the moon. LOLA uses short (6 ns) pulses from a single laser through a Diffractive Optical Element (DOE) to produce a five-beam pattern that illuminates the lunar surface. For each beam, LOLA measures the time of flight (range), pulse spreading (surface roughness), and transmit/return energy (surface reflectance). LOLA will produce a high-resolution global topographic model and global geodetic framework that enables precise targeting, safe landing, and surface mobility to carry out exploratory activities. In addition, it will characterize the polar illumination environment, and image permanently shadowed regions of the lunar surface to identify possible locations of surface ice crystals in shadowed polar craters.

  6. The accuracy of satellite radar altimeter data over the Greenland ice sheet determined from airborne laser data

    DEFF Research Database (Denmark)

    Bamber, J.L.; Ekholm, Simon; Krabill, W.

    1998-01-01

    with airborne laser altimeter data an absolute accuracy typically in the range 2-10 cm +/- 10 cm. Comparison of differences between the radar and laser derived elevations, showed a correlation with surface slope. The difference between the two data sets ranged from 84 cm +/- 79 cm for slopes below 0.1 degrees......The 336 days of the geodetic phase of ERS-1 provides dense coverage, by satellite radar altimetry, of the whole of the Greenland ice sheet. These data have been used to produce a digital elevation model of the ice sheet. The errors present in the altimeter data were investigated via a comparison......, to 10.3 m +/- 8.4 m for a slope of 0.7 degrees ( the half power beam-width of the ERS-1 radar altimeter). An explanation for the behaviour of the difference as a function of surface slope is given in terms of the pattern of surface roughness on the ice sheet....

  7. Searching for Lunar Horizon Glow With the Lunar Orbiter Laser Altimeter (LOLA)

    Science.gov (United States)

    Barker, M. K.; Mazarico, E. M.; McClanahan, T. P.; Sun, X.; Smith, D. E.; Neumann, G. A.; Zuber, M. T.; Head, J. W., III

    2017-12-01

    The dust environment of the Moon is sensitive to the interplanetary meteoroid population and dust transport processes near the lunar surface, and this affects many aspects of lunar surface science and planetary exploration. The interplanetary meteoroid population poses a significant risk to spacecraft, yet it remains one of the more uncertain constituents of the space environment. Observed and hypothesized lunar dust transport mechanisms have included impact-generated dust plumes, electrostatic levitation, and dynamic lofting. Many details of the impactor flux and impact ejection process are poorly understood, a fact highlighted by recent discrepant estimates of the regolith mixing rate. Apollo-era observations of lunar horizon glow (LHG) were interpreted as sunlight forward-scattered by exospheric dust grains levitating in the top meter above the surface or lofted to tens of kilometers in altitude. However, recent studies have placed limits on the dust density orders of magnitude less than what was originally inferred, raising new questions on the time variability of the dust environment. Motivated by the need to better understand dust transport processes and the meteoroid population, the Lunar Orbiter Laser Altimeter (LOLA) aboard the Lunar Reconnaissance Orbiter (LRO) is conducting a campaign to search for LHG with the LOLA Laser Ranging (LR) system. Advantages of this LOLA LHG search include: (1) the LOLA-LR telescope can observe arbitrarily close to the Sun at any time during the year without damaging itself or the other instruments, (2) a long temporal baseline with observations both during and outside of meteor streams, which will improve the chances of detecting LHG, and (3) a focus on altitudes methodology, and preliminary results.

  8. Subsurface Scattered Photons: Friend or Foe? Improving visible light laser altimeter elevation estimates, and measuring surface properties using subsurface scattered photons

    Science.gov (United States)

    Greeley, A.; Kurtz, N. T.; Neumann, T.; Cook, W. B.; Markus, T.

    2016-12-01

    Photon counting laser altimeters such as MABEL (Multiple Altimeter Beam Experimental Lidar) - a single photon counting simulator for ATLAS (Advanced Topographical Laser Altimeter System) - use individual photons with visible wavelengths to measure their range to target surfaces. ATLAS, the sole instrument on NASA's upcoming ICESat-2 mission, will provide scientists a view of Earth's ice sheets, glaciers, and sea ice with unprecedented detail. Precise calibration of these instruments is needed to understand rapidly changing parameters such as sea ice freeboard, and to measure optical properties of surfaces like snow covered ice sheets using subsurface scattered photons. Photons that travel through snow, ice, or water before scattering back to an altimeter receiving system travel farther than photons taking the shortest path between the observatory and the target of interest. These delayed photons produce a negative elevation bias relative to photons scattered directly off these surfaces. We use laboratory measurements of snow surfaces using a flight-tested laser altimeter (MABEL), and Monte Carlo simulations of backscattered photons from snow to estimate elevation biases from subsurface scattered photons. We also use these techniques to demonstrate the ability to retrieve snow surface properties like snow grain size.

  9. Coupled thermo-elastic and optical performance analyses of a reflective baffle for the BepiColombo laser altimeter (BELA) receiver

    Science.gov (United States)

    Heesel, E.; Weigel, T.; Lochmatter, P.; Rugi Grond, E.

    2017-11-01

    For the BepiColombo mission, the extreme thermal environment around Mercury requires good heat shields for the instruments. The BepiColombo Laser altimeter (BELA) Receiver will be equipped with a specular reflective baffle in order to limit the solar power impact. The design uses a Stavroudis geometry with alternating elliptical and hyperbolic vanes to reflect radiation at angles >38° back into space. The thermal loads on the baffle lead to deformations, and the resulting changes in the optical performance can be modeled by ray-tracing. Conventional interfaces, such as Zernike surface fitting, fail to provide a proper import of the mechanical distortions into optical models. We have studied alternative models such as free form surface representations and compared them to a simple modeling approach with straight segments. The performance merit is presented in terms of the power rejection ratio and the absence of specular stray-light.

  10. Low-Amplitude Topographic Features and Textures on the Moon: Initial Results from Detrended Lunar Orbiter Laser Altimeter (LOLA) Topography

    Science.gov (United States)

    Kreslavsky, Mikhail A.; Head, James W.; Neumann, Gregory A.; Zuber, Maria T.; Smith, David E.

    2016-01-01

    Global lunar topographic data derived from ranging measurements by the Lunar Orbiter Laser Altimeter (LOLA) onboard LRO mission to the Moon have extremely high vertical precision. We use detrended topography as a means for utilization of this precision in geomorphological analysis. The detrended topography was calculated as a difference between actual topography and a trend surface defined as a median topography in a circular sliding window. We found that despite complicated distortions caused by the non-linear nature of the detrending procedure, visual inspection of these data facilitates identification of low-amplitude gently-sloping geomorphic features. We present specific examples of patterns of lava flows forming the lunar maria and revealing compound flow fields, a new class of lava flow complex on the Moon. We also highlight the identification of linear tectonic features that otherwise are obscured in the images and topographic data processed in a more traditional manner.

  11. Crater Morphometry and Crater Degradation on Mercury: Mercury Laser Altimeter (MLA) Measurements and Comparison to Stereo-DTM Derived Results

    Science.gov (United States)

    Leight, C.; Fassett, C. I.; Crowley, M. C.; Dyar, M. D.

    2017-01-01

    Two types of measurements of Mercury's surface topography were obtained by the MESSENGER (MErcury Surface Space ENvironment, GEochemisty and Ranging) spacecraft: laser ranging data from Mercury Laser Altimeter (MLA) [1], and stereo imagery from the Mercury Dual Imaging System (MDIS) camera [e.g., 2, 3]. MLA data provide precise and accurate elevation meaurements, but with sparse spatial sampling except at the highest northern latitudes. Digital terrain models (DTMs) from MDIS have superior resolution but with less vertical accuracy, limited approximately to the pixel resolution of the original images (in the case of [3], 15-75 m). Last year [4], we reported topographic measurements of craters in the D=2.5 to 5 km diameter range from stereo images and suggested that craters on Mercury degrade more quickly than on the Moon (by a factor of up to approximately 10×). However, we listed several alternative explanations for this finding, including the hypothesis that the lower depth/diameter ratios we observe might be a result of the resolution and accuracy of the stereo DTMs. Thus, additional measurements were undertaken using MLA data to examine the morphometry of craters in this diameter range and assess whether the faster crater degradation rates proposed to occur on Mercury is robust.

  12. A method for separating Antarctic postglacial rebound and ice mass balance using future ICESat Geoscience Laser Altimeter System, Gravity Recovery and Climate Experiment, and GPS satellite data

    OpenAIRE

    Velicogna, Isabella; Wahr, John

    2002-01-01

    Measurements of ice elevation from the Geoscience Laser Altimeter System (GLAS) aboard the Ice, Cloud, and Land Elevation Satellite can be combined with time-variable geoid measurements from the Gravity Recovery and Climate Experiment (GRACE) satellite mission to learn about ongoing changes in polar ice mass and viscoelastic rebound of the lithosphere under the ice sheet. We estimate the accuracy in recovering the spatially varying ice mass trend and postglacial rebound signals for Antarctica...

  13. High Resolution Airborne InSAR DEM of Bagley Ice Valley, South-central Alaska: Geodetic Validation with Airborne Laser Altimeter Data

    Science.gov (United States)

    Muskett, R. R.; Lingle, C. S.; Echelmeyer, K. A.; Valentine, V. B.; Elsberg, D.

    2001-12-01

    Bagley Ice Valley, in the St. Elias and Chugach Mountains of south-central Alaska, is an integral part of the largest connected glacierized terrain on the North American continent. From the flow divide between Mt. Logan and Mt. St. Elias, Bagley Ice Valley flows west-northwest for some 90 km down a slope of less than 1o, at widths up to 15 km, to a saddle-gap where it turns south-west to become Bering Glacier. During 4-13 September 2000, an airborne survey of Bagley Ice Valley was performed by Intermap Technologies, Inc., using their Star-3i X-band SAR interferometer. The resulting digital elevation model (DEM) covers an area of 3243 km2. The DEM elevations are orthometric heights, in meters above the EGM96 geoid. The horizontal locations of the 10-m postings are with respect to the WGS84 ellipsoid. On 26 August 2000, 9 to 18 days prior to the Intermap Star-3i survey, a small-aircraft laser altimeter profile was acquired along the central flow line for validation. The laser altimeter data consists of elevations above the WGS84 ellipsoid and orthometric heights above GEOID99-Alaska. Assessment of the accuracy of the Intermap Star-3i DEM was made by comparison of both the DEM orthometric heights and elevations above the WGS84 ellipsoid with the laser altimeter data. Comparison of the orthometric heights showed an average difference of 5.4 +/- 1.0 m (DEM surface higher). Comparison of elevations above the WGS84 ellipsoid showed an average difference of -0.77 +/- 0.93 m (DEM surface lower). This indicates that the X-band Star-3i interferometer was penetrating the glacier surface by an expected small amount. The WGS84 comparison is well within the 3 m RMS accuracy quoted for GT-3 DEM products. Snow accumulation may have occurred, however, on Bagley Ice Valley between 26 August and 4-13 September 2000. This will be estimated using a mass balance model and used to correct the altimeter-derived surface heights. The new DEM of Bagley Ice Valley will provide a reference

  14. Quantifying Seasonal Skill In Coupled Sea Ice Models Using Freeboard Measurements From Spaceborne Laser Altimeters

    Science.gov (United States)

    2016-06-01

    Data collection periods during the ICESat mission were influenced by the presence of atmospheric clouds and aerosols, and also LASER malfunctions. Upon...measurements after that satellite is launched next year. 14. subject terms Arctic, climate change, Regional Arctic System Model, altimetry...measurements, sea ice, sea ice thickness, freeboard, ICESat, ICESat-2, climate model, coupled model, Operation IceBridge 15. NUMBER OF PAGES 147 16

  15. Lunar Impact Basins: Stratigraphy, Sequence and Ages from Superposed Impact Crater Populations Measured from Lunar Orbiter Laser Altimeter (LOLA) Data

    Science.gov (United States)

    Fassett, C. I.; Head, J. W.; Kadish, S. J.; Mazarico, E.; Neumann, G. A.; Smith, D. E.; Zuber, M. T.

    2012-01-01

    Impact basin formation is a fundamental process in the evolution of the Moon and records the history of impactors in the early solar system. In order to assess the stratigraphy, sequence, and ages of impact basins and the impactor population as a function of time, we have used topography from the Lunar Orbiter Laser Altimeter (LOLA) on the Lunar Reconnaissance Orbiter (LRO) to measure the superposed impact crater size-frequency distributions for 30 lunar basins (D = 300 km). These data generally support the widely used Wilhelms sequence of lunar basins, although we find significantly higher densities of superposed craters on many lunar basins than derived by Wilhelms (50% higher densities). Our data also provide new insight into the timing of the transition between distinct crater populations characteristic of ancient and young lunar terrains. The transition from a lunar impact flux dominated by Population 1 to Population 2 occurred before the mid-Nectarian. This is before the end of the period of rapid cratering, and potentially before the end of the hypothesized Late Heavy Bombardment. LOLA-derived crater densities also suggest that many Pre-Nectarian basins, such as South Pole-Aitken, have been cratered to saturation equilibrium. Finally, both crater counts and stratigraphic observations based on LOLA data are applicable to specific basin stratigraphic problems of interest; for example, using these data, we suggest that Serenitatis is older than Nectaris, and Humboldtianum is younger than Crisium. Sample return missions to specific basins can anchor these measurements to a Pre-Imbrian absolute chronology.

  16. Designing of Raman laser

    International Nuclear Information System (INIS)

    Zidan, M. D.; Al-Awad, F.; Alsous, M. B.

    2005-01-01

    In this work, we describe the design of the Raman laser pumped by Frequency doubled Nd-YAG laser (λ=532 nm) to generate new laser wavelengths by shifting the frequency of the Nd-YAG laser to Stokes region (λ 1 =683 nm, λ 2 =953.6 nm, λ 3 =1579.5 nm) and Antistokes region (λ ' 1 =435 nm, λ ' 2 =369.9 nm, λ ' 3=319.8 nm). Laser resonator has been designed to increase the laser gain. It consists of two mirrors, the back mirror transmits the pump laser beam (λ=532 nm) through the Raman tube and reflects all other generated Raman laser lines. Four special front mirrors were made to be used for the four laser lines λ 1 =683 nm, λ 2 =953.6 nm and λ ' 1 = 435 nm, λ ' 2 =369.9 nm. The output energy for the lines υ 1 s, υ 2 s, υ 1 as,υ 2 as was measured. The output energy of the Raman laser was characterized for different H 2 pressure inside the tube. (Author)

  17. Lunar Phase Function at 1064 Nm from Lunar Orbiter Laser Altimeter Passive and Active Radiometry

    Science.gov (United States)

    Barker, M. K.; Sun, X.; Mazarico, E.; Neumann, G. A.; Zuber, M. T.; Smith, D. E.

    2016-01-01

    We present initial calibration and results of passive radiometry collected by the Lunar Orbiter Laser Al- timeter onboard the Lunar Reconnaissance Orbiter over the course of 12 months. After correcting for time- and temperature-dependent dark noise and detector responsivity variations, the LOLA passive radiometry measurements are brought onto the absolute radiance scale of the SELENE Spectral Profiler. The resulting photometric precision is estimated to be approximately 5%. We leverage the unique ability of LOLA to measure normal albedo to explore the 1064 nm phase function's dependence on various geologic parameters. On a global scale, we find that iron abundance and optical maturity (quantified by FeO and OMAT) are the dominant controlling parameters. Titanium abundance (TiO2 ), surface roughness on decimeter to decameter scales, and soil thermophysical properties have a smaller effect, but the latter two are correlated with OMAT, indicating that exposure age is the driving force behind their effects in a globally-averaged sense. The phase function also exhibits a dependence on surface slope at approximately 300 m baselines, possibly the result of mass wasting exposing immature material and/or less space weathering due to reduced sky visibility. Modeling the photometric function in the Hapke framework, we find that, relative to the highlands, the maria exhibit decreased backscattering, a smaller opposition effect (OE) width, and a smaller OE amplitude. Immature highlands regolith has a higher backscattering fraction and a larger OE width compared to mature highlands regolith. Within the maria, the backscattering fraction and OE width show little dependence on TiO2 and OMAT. Variations in the phase function shape at large phase angles are observed in and around the Copernican-aged Jackson crater, including its dark halo, a putative impact melt deposit. Finally, the phase function of the Reiner Gamma Formation behaves more optically immature than is typical for its

  18. Mineralogy and Iron Content of the Lunar Polar Regions Using the Kaguya Spectral Profiler and the Lunar Orbiter Laser Altimeter

    Science.gov (United States)

    Lemelin, M.; Lucey, P. G.; Trang, D.; Jha, K.

    2016-12-01

    The lunar polar regions are of high scientific interest, but the extreme lighting conditions have made quantitative analyses using reflectance spectra difficult; some regions are in permanent shadow, and flat surfaces are difficult to correct photometrically due to the extreme grazing incidence and low signal available. Thus, most mineral maps derived from visible and near infrared reflectance spectra have been constrained to within 50° in latitude. The mineralogy of the polar regions, or 44% of the lunar surface, is almost entirely unknown. A few studies have provided compositional analysis based on the spectral shape (where strong absorption bands were present) of lithologies dominated by one or two minerals. In this study, we take a novel approach and use strong signal and well-calibrated reflectance acquired by two different instruments, the Kaguya Spectra Profiler (SP) and the Lunar Orbiter Laser Altimeter (LOLA), in order to derive the first FeO and mineral maps of the polar regions at a spatial resolution of 1 km per pixel. We use reflectance ratios from SP and calibrated reflectance data from LOLA to derive the first polar maps of FeO, which are within 2 wt.% of the FeO measured by the Lunar Prospector Gamma-Ray spectrometer up to 85° in latitude. We then use the reflectance data from SP and Hapke radiative transfer model to compute the abundance of olivine, low-calcium pyroxene, high-calcium pyroxene and plagioclase, using FeO as a constraint. The radiative transfer model yields an error in mineral abundances of 9 wt.%. We use the mineral maps to study the composition of 27 central peaks and 5 basin rings in the polar regions, and relate their composition to their depth of origin in the lunar crust. We find that the central peaks and basin rings in Feldspathic Highlands Terrane are mostly anorthositic in composition, with modal plagioclase content ranging between 66 and 92 wt.%. The central peaks and basin rings in the South Pole-Aitken basin are noritic

  19. Performance Considerations for the SIMPL Single Photon, Polarimetric, Two-Color Laser Altimeter as Applied to Measurements of Forest Canopy Structure and Composition

    Science.gov (United States)

    Dabney, Philip W.; Harding, David J.; Valett, Susan R.; Vasilyev, Aleksey A.; Yu, Anthony W.

    2012-01-01

    The Slope Imaging Multi-polarization Photon-counting Lidar (SIMPL) is a multi-beam, micropulse airborne laser altimeter that acquires active and passive polarimetric optical remote sensing measurements at visible and near-infrared wavelengths. SIMPL was developed to demonstrate advanced measurement approaches of potential benefit for improved, more efficient spaceflight laser altimeter missions. SIMPL data have been acquired for wide diversity of forest types in the summers of 2010 and 2011 in order to assess the potential of its novel capabilities for characterization of vegetation structure and composition. On each of its four beams SIMPL provides highly-resolved measurements of forest canopy structure by detecting single-photons with 15 cm ranging precision using a narrow-beam system operating at a laser repetition rate of 11 kHz. Associated with that ranging data SIMPL provides eight amplitude parameters per beam unlike the single amplitude provided by typical laser altimeters. Those eight parameters are received energy that is parallel and perpendicular to that of the plane-polarized transmit pulse at 532 nm (green) and 1064 nm (near IR), for both the active laser backscatter retro-reflectance and the passive solar bi-directional reflectance. This poster presentation will cover the instrument architecture and highlight the performance of the SIMPL instrument with examples taken from measurements for several sites with distinct canopy structures and compositions. Specific performance areas such as probability of detection, after pulsing, and dead time, will be highlighted and addressed, along with examples of their impact on the measurements and how they limit the ability to accurately model and recover the canopy properties. To assess the sensitivity of SIMPL's measurements to canopy properties an instrument model has been implemented in the FLIGHT radiative transfer code, based on Monte Carlo simulation of photon transport. SIMPL data collected in 2010 over

  20. Surge of Bering Glacier and Bagley Ice Field: Parameterization of surge characteristics based on automated analysis of crevasse image data and laser altimeter data

    Science.gov (United States)

    Stachura, M.; Herzfeld, U. C.; McDonald, B.; Weltman, A.; Hale, G.; Trantow, T.

    2012-12-01

    The dynamical processes that occur during the surge of a large, complex glacier system are far from being understood. The aim of this paper is to derive a parameterization of surge characteristics that captures the principle processes and can serve as the basis for a dynamic surge model. Innovative mathematical methods are introduced that facilitate derivation of such a parameterization from remote-sensing observations. Methods include automated geostatistical characterization and connectionist-geostatistical classification of dynamic provinces and deformation states, using the vehicle of crevasse patterns. These methods are applied to analyze satellite and airborne image and laser altimeter data collected during the current surge of Bering Glacier and Bagley Ice Field, Alaska.

  1. Stratigraphy, Sequence, and Crater Populations of Lunar Impact Basins from Lunar Orbiter Laser Altimeter (LOLA) Data: Implications for the Late Heavy Bombardment

    Science.gov (United States)

    Fassett, C. I.; Head, J. W.; Kadish, S. J.; Mazarico, E.; Neumann, G. A.; Smith, D. E.; Zuber, M. T.

    2012-01-01

    New measurements of the topography of the Moon from the Lunar Orbiter Laser Altimeter (LOLA)[1] provide an excellent base-map for analyzing the large crater population (D.20 km)of the lunar surface [2, 3]. We have recently used this data to calculate crater size-frequency distributions (CSFD) for 30 lunar impact basins, which have implications for their stratigraphy and sequence. These data provide an avenue for assessing the timing of the transitions between distinct crater populations characteristic of ancient and young lunar terrains, which has been linked to the late heavy bombardment (LHB). We also use LOLA data to re-examine relative stratigraphic relationships between key lunar basins.

  2. A new, high-resolution digital elevation model of Greenland fully validated with airborne laser altimeter data

    DEFF Research Database (Denmark)

    Bamber, J.L.; Ekholm, Simon; Krabill, W.B.

    2001-01-01

    were corrected for a slope-dependent bias that had been identified in a previous study. The radar altimetry was supplemented with stereophotogrammetric data sets, synthetic aperture radar interferometry, and digitized cartographic maps over regions of bare rock and where gaps in the satellite altimeter...... the bare rock areas the accuracy ranged from 20 to 200 m, dependent on the data source available. The new digital elevation model was used as an input data set for a positive degree day model of ablation. The new elevation model was found to reduce ablation by only 2% compared with using an older, 2.5-km...

  3. Comprehensive study of electro-optic and passive Q-switching in solid state lasers for altimeter applications

    Science.gov (United States)

    Bhardwaj, Atul; Agrawal, Lalita; Pal, Suranjan; Kumar, Anil

    2006-12-01

    Laser Science and Technology Center (LASTEC), Delhi, is developing a space qualified diode pumped Nd: YAG laser transmitter capable of generating 10 ns pulses of 30 mJ energy @ 10 pps. This paper presents the results of experiments for comparative studies between electro-optic and passively Q-switched Nd: YAG laser in a crossed porro prism based laser resonator. Experimental studies have been performed by developing an economical bench model of flash lamp pumped Nd: YAG laser (rod dimension, \

  4. Photon counting altimeter and lidar for air and spaceborne applications

    Science.gov (United States)

    Vacek, Michael; Michalek, Vojtech; Peca, Marek; Prochazka, Ivan; Blazej, Josef; Kodet, Jan

    2011-06-01

    We are presenting the concept and preliminary design of modular multipurpose device for space segment: single photon counting laser altimeter, atmospheric lidar, laser transponder and one way laser ranging receiver. For all the mentioned purposes, the same compact configuration of the device is appropriate. Overall estimated device weight should not exceed 5 kg with the power consumption below 10 W. The device will consists of three main parts, namely, receiver, transmitter and control and processing unit. As a transmitter a commercial solid state laser at 532 nm wavelength with 10 mW power will be used. The transmitter optics will have a diameter at most of 50 mm. The laser pulse width will be of hundreds of picoseconds order. For the laser altimeter and atmospheric lidar application, the repetition rate of 10 kHz is planned in order to obtain sufficient number of data for a distance value computing. The receiver device will be composed of active quenched Single Photon Avalanche Diode module, tiny optics, and narrow-band optical filter. The core part of the control and processing unit including high precision timing unit is implemented using single FPGA chip. The preliminary device concept includes considerations on energy balance, and statistical algorithms to meet all the mentioned purposes. Recently, the bread board version of the device is under construction in our labs. The concept, construction, and timing results will be presented.

  5. Mid-Latitude versus Polar-Latitude Transitional Impact Craters: Geometric Properties from Mars Orbiter Laser Altimeter (MOLA) Observations and Viking Images

    Science.gov (United States)

    Matias, A.; Garvin, J. B.; Sakimoto, S. E. H.

    1998-01-01

    One intriguing aspect of martian impact crater morphology is the change of crater cavity and ejecta characteristics from the mid-latitudes to the polar regions. This is thought to reflect differences in target properties such as an increasing presence of ice in the polar regions. Previous image-based efforts concerning martian crater morphology has documented some aspects of this, but has been hampered by the lack of adequate topography data. Recent Mars Orbiter Laser Altimeter (MOLA) topographic profiles provide a quantitative perspective for interpreting the detailed morphologies of martian crater cavities and ejecta morphology. This study is a preliminary effort to quantify the latitude-dependent differences in morphology with the goal of identifying target-dependent and crater modification effects from the combined of images and MOLA topography. We combine the available MOLA profiles and the corresponding Viking Mars Digital Image Mosaics (MDIMS), and high resolution Viking Orbiter images to focus on two transitional craters; one on the mid-latitudes, and one in the North Polar region. One MOLA pass (MGS Orbit 34) traverses the center of a 15.9 km diameter fresh complex crater located at 12.8degN 83.8degE on the Hesperian ridge plains unit (Hvr). Viking images, as well as MOLA data, show that this crater has well developed wall terraces and a central peak with 429 m of relative relief. Three MOLA passes have been acquired for a second impact crater, which is located at 69.5degN 41degE on the Vastitas Borealis Formation. This fresh rampart crater lacks terraces and central peak structures and it has a depth af 579 m. Correlation between images and MOLA topographic profiles allows us to construct basic facies maps of the craters. Eight main units were identified, four of which are common on both craters.

  6. Physics of short-wavelength-laser design

    Energy Technology Data Exchange (ETDEWEB)

    Hagelstein, P.L.

    1981-01-01

    The physics and design of vuv and soft x-ray lasers pumped by ICF class high intensity infrared laser drivers are described (for example, the SHIVA laser facility at LLNL). Laser design and physics issues are discussed in the case of a photoionization pumping scheme involving Ne II and line pumping schemes involving H-like and He-like neon.

  7. ARGOS laser system mechanical design

    Science.gov (United States)

    Deysenroth, M.; Honsberg, M.; Gemperlein, H.; Ziegleder, J.; Raab, W.; Rabien, S.; Barl, L.; Gässler, W.; Borelli, J. L.

    2014-07-01

    ARGOS, a multi-star adaptive optics system is designed for the wide-field imager and multi-object spectrograph LUCI on the LBT (Large Binocular Telescope). Based on Rayleigh scattering the laser constellation images 3 artificial stars (at 532 nm) per each of the 2 eyes of the LBT, focused at a height of 12 km (Ground Layer Adaptive Optics). The stars are nominally positioned on a circle 2' in radius, but each star can be moved by up to 0.5' in any direction. For all of these needs are following main subsystems necessary: 1. A laser system with its 3 Lasers (Nd:YAG ~18W each) for delivering strong collimated light as for LGS indispensable. 2. The Launch system to project 3 beams per main mirror as a 40 cm telescope to the sky. 3. The Wave Front Sensor with a dichroic mirror. 4. The dichroic mirror unit to grab and interpret the data. 5. A Calibration Unit to adjust the system independently also during day time. 6. Racks + platforms for the WFS units. 7. Platforms and ladders for a secure access. This paper should mainly demonstrate how the ARGOS Laser System is configured and designed to support all other systems.

  8. New evidence for surface water ice in small-scale cold traps and in three large craters at the north polar region of Mercury from the Mercury Laser Altimeter

    Science.gov (United States)

    Deutsch, Ariel N.; Neumann, Gregory A.; Head, James W.

    2017-09-01

    The Mercury Laser Altimeter (MLA) measured surface reflectance, rs, at 1064 nm. On Mercury, most water-ice deposits have anomalously low rs values indicative of an insulating layer beneath which ice is buried. Previous detections of surface water ice (without an insulating layer) were limited to seven possible craters. Here we map rs in three additional permanently shadowed craters that host radar-bright deposits. Each crater has a mean rs value >0.3, suggesting that water ice is exposed at the surface without an overlying insulating layer. We also identify small-scale cold traps (rs >0.3 and permanent shadows have biannual maximum surface temperatures <100 K. We suggest that a substantial amount of Mercury's water ice is not confined to large craters but exists within microcold traps, within rough patches and intercrater terrain.

  9. Advances in laser solenoid fusion reactor design

    International Nuclear Information System (INIS)

    Steinhauer, L.C.; Quimby, D.C.

    1978-01-01

    The laser solenoid is an alternate fusion concept based on a laser-heated magnetically-confined plasma column. The reactor concept has evolved in several systems studies over the last five years. We describe recent advances in the plasma physics and technology of laser-plasma coupling. The technology advances include progress on first walls, inner magnet design, confinement module design, and reactor maintenance. We also describe a new generation of laser solenoid fusion and fusion-fission reactor designs

  10. Short Pulse Laser Applications Design

    International Nuclear Information System (INIS)

    Town, R.J.; Clark, D.S.; Kemp, A.J.; Lasinski, B.F.; Tabak, M.

    2008-01-01

    We are applying our recently developed, LDRD-funded computational simulation tool to optimize and develop applications of Fast Ignition (FI) for stockpile stewardship. This report summarizes the work performed during a one-year exploratory research LDRD to develop FI point designs for the National Ignition Facility (NIF). These results were sufficiently encouraging to propose successfully a strategic initiative LDRD to design and perform the definitive FI experiment on the NIF. Ignition experiments on the National Ignition Facility (NIF) will begin in 2010 using the central hot spot (CHS) approach, which relies on the simultaneous compression and ignition of a spherical fuel capsule. Unlike this approach, the fast ignition (FI) method separates fuel compression from the ignition phase. In the compression phase, a laser such as NIF is used to implode a shell either directly, or by x rays generated from the hohlraum wall, to form a compact dense (∼300 g/cm 3 ) fuel mass with an areal density of ∼3.0 g/cm 2 . To ignite such a fuel assembly requires depositing ∼20kJ into a ∼35 (micro)m spot delivered in a short time compared to the fuel disassembly time (∼20ps). This energy is delivered during the ignition phase by relativistic electrons generated by the interaction of an ultra-short high-intensity laser. The main advantages of FI over the CHS approach are higher gain, a lower ignition threshold, and a relaxation of the stringent symmetry requirements required by the CHS approach. There is worldwide interest in FI and its associated science. Major experimental facilities are being constructed which will enable 'proof of principle' tests of FI in integrated subignition experiments, most notably the OMEGA-EP facility at the University of Rochester's Laboratory of Laser Energetics and the FIREX facility at Osaka University in Japan. Also, scientists in the European Union have recently proposed the construction of a new FI facility, called HiPER, designed to

  11. Design windows of laser fusion power plants and conceptual design of laser-diode pumped slab laser

    International Nuclear Information System (INIS)

    Kozaki, Y.; Eguchi, T.; Izawa, Y.

    1999-01-01

    An analysis of the design space available to laser fusion power plants has been carried out, in terms of design key parameters such as target gain, laser energy and laser repetition rate, the number of fusion react ion chambers, and plant size. The design windows of economically attractive laser fusion plants is identified with the constraints of key design parameters and the cost conditions. Especially, for achieving high repetition rate lasers, we have proposed and designed a diode-pumped solid-state laser driver which consists of water-cooled zig-zag path slab amplifiers. (author)

  12. Design study of laser fusion rocket

    International Nuclear Information System (INIS)

    Nakashima, Hideki; Shoyama, Hidetoshi; Kanda, Yukinori

    1991-01-01

    A design study was made on a rocket powered by laser fusion. Dependence of its flight performance on target gain, driver repetition rate and fuel composition was analyzed to obtain optimal design parameters of the laser fusion rocket. The results indicate that the laser fusion rocket fueled with DT or D 3 He has the potential advantages over other propulsion systems such as fission rocket for interplanetary travel. (author)

  13. Laser and photonic systems design and integration

    CERN Document Server

    Nof, Shimon Y; Cheng, Gary J

    2014-01-01

    New, significant scientific discoveries in laser and photonic technologies, systems perspectives, and integrated design approaches can improve even further the impact in critical areas of challenge. Yet this knowledge is dispersed across several disciplines and research arenas. Laser and Photonic Systems: Design and Integration brings together a multidisciplinary group of experts to increase understanding of the ways in which systems perspectives may influence laser and photonic innovations and application integration.By bringing together chapters from leading scientists and technologists, ind

  14. Multimegajoule laser project: new compact multipass laser design

    International Nuclear Information System (INIS)

    Holzrichter, J.F.

    1985-01-01

    A simple laser design that has the fewest laser components of all fusion systems that the authors have studied and that packs closely, thus minimizing space requirements is shown. The Advanced Laser Program objectives are determined by the requirements of the subsystems. The requirements consists of the following elements: high damage thresholds on reflectors; AR layers and dichroic coatings; high-efficiency amplifiers; low-cost production of laser glass, pulse power, and optical elements; and special optical elements, such as an effective phase conjugator and isolator. The combination of a compact architecture and lower-cost, higher-performance components can lead to significant reduction in overall system cost

  15. Design of DFB fibre lasers

    DEFF Research Database (Denmark)

    Lauridsen, Vibeke Claudia; Povlsen, Jørn Hedegaard; Varming, Poul

    1998-01-01

    A numerical model for erbium distributed feedback (DFB) fibre lasers is presented. The model is used to optimise the location of a discrete phase-shift to obtain maximum output power. For DFB fibre lasers of up to 10cm in length it is shown that the influence of Kerr nonlinearity with respect to ...... to output power is negligible....

  16. SOLASE: a conceptual laser fusion reactor design

    International Nuclear Information System (INIS)

    Conn, R.W.; Abdel-Khalik, S.I.; Moses, G.A.

    1977-12-01

    The SOLASE conceptual laser fusion reactor has been designed to elucidate the technological problems posed by inertial confinement fusion reactors. This report contains a detailed description of all aspects of the study including the physics of pellet implosion and burn, optics and target illumination, last mirror design, laser system analysis, cavity design, pellet fabrication and delivery, vacuum system requirements, blanket design, thermal hydraulics, tritium analysis, neutronics calculations, radiation effects, stress analysis, shield design, reactor and plant building layout, maintenance procedures, and power cycle design. The reactor is designed as a 1000 MW/sub e/ unit for central station electric power generation

  17. SOLASE: a conceptual laser fusion reactor design

    International Nuclear Information System (INIS)

    Conn, R.W.; Abdel-Khalik, S.I.; Moses, G.A.

    1977-12-01

    The SOLASE conceptual laser fusion reactor has been designed to elucidate the technological problems posed by inertial confinement fusion ractors. This report contains a detailed description of all aspects of the study including the physics of pellet implosion and burn, optics and target illumination, last mirror design, laser system analysis, cavity design, pellet fabrication and delivery, vacuum system requirements, blanket design, thermal hydraulics, tritium analysis, neutronics calculations, radiation effects, stress analysis, shield design, reactor and plant building layout, maintenance procedures, and power cycle design. The reactor is designed as a 1000 MW/sub e/ unit for central station electric power generation

  18. Pellet design for a laser fusion reactor

    International Nuclear Information System (INIS)

    Thiessen, A.R.; Nuckolls, J.

    1974-01-01

    The requirements for laser fusion pellet design are discussed. Computer calculations are presented of a capsule consisting of a spherical solid drop of DT surrounded by a concentric shell of DT. Gains greater than 40 fold are achieved with laser energies of approximately 0.5 MJ, and peak powers of about 10 16 W. (U.S.)

  19. Constraining the thickness of polar ice deposits on Mercury using the Mercury Laser Altimeter and small craters in permanently shadowed regions

    Science.gov (United States)

    Deutsch, Ariel N.; Head, James W.; Chabot, Nancy L.; Neumann, Gregory A.

    2018-05-01

    Radar-bright deposits at the poles of Mercury are located in permanently shadowed regions, which provide thermally stable environments for hosting and retaining water ice on the surface or in the near subsurface for geologic timescales. While the areal distribution of these radar-bright deposits is well characterized, their thickness, and thus their total mass and volume, remain poorly constrained. Here we derive thickness estimates for selected water-ice deposits using small, simple craters visible within the permanently shadowed, radar-bright deposits. We examine two endmember scenarios: in Case I, these craters predate the emplacement of the ice, and in Case II, these craters postdate the emplacement of the ice. In Case I, we find the difference between estimated depths of the original unfilled craters and the measured depths of the craters to find the estimated infill of material. The average estimated infilled material for 9 craters assumed to be overlain with water ice is ∼ 41-14+30 m, where 1-σ standard error of the mean is reported as uncertainty. Reported uncertainties are for statistical errors only. Additional systematic uncertainty may stem from georeferencing the images and topographic datasets, from the radial accuracy of the altimeter measurements, or from assumptions in our models including (1) ice is flat in the bowl-shaped crater and (2) there is negligible ice at the crater rims. In Case II, we derive crater excavation depths to investigate the thickness of the ice layer that may have been penetrated by the impact. While the absence of excavated regolith associated with the small craters observed suggests that impacts generally do not penetrate through the ice deposit, the spatial resolution and complex illumination geometry of images may limit the observations. Therefore, it is not possible to conclude whether the small craters in this study penetrate through the ice deposit, and thus Case II does not provide a constraint on the ice thickness

  20. Laser solenoid fusion--fission design

    International Nuclear Information System (INIS)

    Steinhauer, L.C.; Taussig, R.T.

    1976-01-01

    The dependence of breeding performance on system engineering parameters is examined for laser solenoid fusion-fission reactors. Reactor performance is found to be relatively insensitive to most of the engineering parameters, and compact designs can be built based on reasonable technologies. Point designs are described for the prototype series of reactors (mid-term technologies) and for second generation systems (advanced technologies). It is concluded that the laser solenoid has a good probability of timely application to fuel breeding needs

  1. Closed cycle electric discharge laser design investigation

    Science.gov (United States)

    Baily, P. K.; Smith, R. C.

    1978-01-01

    Closed cycle CO2 and CO electric discharge lasers were studied. An analytical investigation assessed scale-up parameters and design features for CO2, closed cycle, continuous wave, unstable resonator, electric discharge lasing systems operating in space and airborne environments. A space based CO system was also examined. The program objectives were the conceptual designs of six CO2 systems and one CO system. Three airborne CO2 designs, with one, five, and ten megawatt outputs, were produced. These designs were based upon five minute run times. Three space based CO2 designs, with the same output levels, were also produced, but based upon one year run times. In addition, a conceptual design for a one megawatt space based CO laser system was also produced. These designs include the flow loop, compressor, and heat exchanger, as well as the laser cavity itself. The designs resulted in a laser loop weight for the space based five megawatt system that is within the space shuttle capacity. For the one megawatt systems, the estimated weight of the entire system including laser loop, solar power generator, and heat radiator is less than the shuttle capacity.

  2. Large laser system facility design

    International Nuclear Information System (INIS)

    Gilmartin, T.J.

    1983-01-01

    Optical stability of foundations and support structures, environmental control, close-in subsystem integration, spatial organization, materiel flow and access to remote subsystems is discussed and compared for four laser facilities: The Special Isotope Separation Laboratory, Argus, Shiva/Nova, and Firepond

  3. SLICER Airborne Laser Altimeter Characterization of Canopy Structure and Sub-canopy Topography for the BOREAS Northern and Southern Study Regions: Instrument and Data Product Description

    Science.gov (United States)

    Hall, Forrest G. (Editor); Nickeson, Jaime (Editor); Harding, D. J.; Blair, J. B.; Rabine, D. L.; Still, K. L.

    2000-01-01

    SLICER data were acquired in support of BOREAS at all of the TF sites in the SSA and NSA, and along transects between the study areas. Data were acquired on 5 days between 18-Jul and 30-Jul-1996. Each coverage of a tower site is typically 40 km in length, with a minimum of 3 and a maximum of 10 lines across each tower oriented in a variety of azimuths. The SLICER data were acquired simultaneously with ASAS hyperspectral, multiview angle images. The SLICER Level 3 products consist of binary files for each flight line with a data record for each laser shot composed of 13 parameters and a 600-byte waveform that is the raw record of the backscatter laser energy reflected from Earth's surface. The SLICER data are stored in a combination of ASCII and binary data files.

  4. Unstable Resonator Retrofitted Handheld Laser Designator

    Science.gov (United States)

    1978-06-01

    retrofitted with a negative-branch unstable resona- tor laser and hybrid pump cavity in place of the conventional plane-mirror/ porro prism resonator and...directed by prism B to an expanding telescope, shared with the viewing system of the designator. The actual, unfolded resonator length is approxi...was performed based on using a plane- parallel cavity consisting of a 47% reflectivity output coupler, porro - prism reflector, and the same LiNb03

  5. New laser design for NIR lidar applications

    Science.gov (United States)

    Vogelmann, H.; Trickl, T.; Perfahl, M.; Biggel, S.

    2018-04-01

    Recently, we quantified the very high spatio-temporal short term variability of tropospheric water vapor in a three dimensional study [1]. From a technical point of view this also depicted the general requirement of short integration times for recording water-vapor profiles with lidar. For this purpose, the only suitable technique is the differential absorption lidar (DIAL) working in the near-infrared (NIR) spectral region. The laser emission of most water vapor DIAL systems is generated by Ti:sapphire or alexandrite lasers. The water vapor absorption band at 817 nm is predominated for the use of Ti:sapphire. We present a new concept of transversely pumping in a Ti:Sapphire amplification stage as well as a compact laser design for the generation of single mode NIR pulses with two different DIAL wavelengths inside a single resonator. This laser concept allows for high output power due to repetitions rates up to 100Hz or even more. It is, because of its compactness, also suitable for mobile applications.

  6. Scanning laser ophthalmoscope design with adaptive optics

    OpenAIRE

    Laut, SP; Jones, SM; Olivier, SS; Werner, JS

    2005-01-01

    A design for a high-resolution scanning instrument is presented for in vivo imaging of the human eye at the cellular scale. This system combines adaptive optics technology with a scanning laser ophthalmoscope (SLO) to image structures with high lateral (∼2 μm) resolution. In this system, the ocular wavefront aberrations that reduce the resolution of conventional SLOs are detected by a Hartmann-Shack wavefront sensor, and compensated with two deformable mirrors in a closed-loop for dynamic cor...

  7. IFE Power Plant design principles. Drivers. Solid state laser drivers

    International Nuclear Information System (INIS)

    Nakai, S.; Andre, M.; Krupke, W.F.; Mak, A.A.; Soures, J.M.; Yamanaka, M.

    1995-01-01

    The present status of solid state laser drivers for an inertial confinement thermonuclear fusion power plant is discussed. In particular, the feasibility of laser diode pumped solid state laser drivers from both the technical and economic points of view is briefly reviewed. Conceptual design studies showed that they can, in principle, satisfy the design requirements. However, development of new solid state materials with long fluorescence lifetimes and good thermal characteristics is a key issue for laser diode pumped solid state lasers. With the advent of laser diode pumping many materials which were abandoned in the past can presently be reconsidered as viable candidates. It is also concluded that it is important to examine the technical requirements for solid state lasers in relation to target performance criteria. The progress of laser diode pumped lasers in industrial applications should also be closely watched to provide additional information on the economic feasibility of this type of driver. 15 refs, 9 figs, 2 tabs

  8. Conceptual design of laser fusion reactor KOYO-fast

    International Nuclear Information System (INIS)

    Tomabechi, K.; Kozaki, Y.; Norimatsu, T.

    2006-01-01

    A conceptual design of the laser fusion reactor KOYO-F based on the fast ignition scheme is reported including the target design, the laser system and the design for chamber. A Yb-YAG ceramic laser operated at 200 K is the primary candidate for the compression laser and an OPCPA (optical parametric chirped pulse amplification) system is the one for the ignition laser. The chamber is basically a wet wall type but the fire position is vertically off-set to simplify the protection scheme of the ceiling. The target consists of foam insulated, cryogenic DT shells with a LiPb, reentrant guide-cone. (authors)

  9. Optical design considerations for laser fusion reactors

    International Nuclear Information System (INIS)

    Monsler, M.J.; Maniscalco, J.A.

    1977-09-01

    The plan for the development of commercial inertial confinement fusion (ICF) power plants is discussed, emphasizing the utilization of the unique features of laser fusion to arrive at conceptual designs for reactors and optical systems which minimize the need for advanced materials and techniques requiring expensive test facilities. A conceptual design for a liquid lithium fall reactor is described which successfully deals with the hostile x-ray and neutron environment and promises to last the 30 year plant lifetime. Schemes for protecting the final focusing optics are described which are both compatible with this reactor system and show promise of surviving a full year in order to minimize costly downtime. Damage mechanisms and protection techniques are discussed, and a recommendation is made for a high f-number metal mirror final focusing system

  10. Gas flow parameters in laser cutting of wood- nozzle design

    Science.gov (United States)

    Kali Mukherjee; Tom Grendzwell; Parwaiz A.A. Khan; Charles McMillin

    1990-01-01

    The Automated Lumber Processing System (ALPS) is an ongoing team research effort to optimize the yield of parts in a furniture rough mill. The process is designed to couple aspects of computer vision, computer optimization of yield, and laser cutting. This research is focused on optimizing laser wood cutting. Laser machining of lumber has the advantage over...

  11. National Ignition Facility system design requirements Laser System SDR002

    International Nuclear Information System (INIS)

    Larson, D.W.; Bowers, J.M.; Bliss, E.S.; Karpenko, V.P.; English, E.

    1996-01-01

    This System Design Requirement document establishes the performance, design, development, and test requirements for the NIP Laser System. The Laser System generates and delivers high-power optical pulses to the target chamber, and is composed of all optical puke creating and transport elements from Puke Generation through Final Optics as well as the special equipment that supports, energizes and controls them. The Laser System consists of the following WBS elements: 1.3 Laser System 1.4 Beam Transport System 1.6 Optical Components 1.7 Laser Control 1.8.7 Final Optics

  12. Design and physical features of inductive coaxial copper vapor lasers

    Energy Technology Data Exchange (ETDEWEB)

    Batenin, V. M. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Kazaryan, M. A. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); Karpukhin, V. T. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Lyabin, N. A. [Istok Research and Production Corporation (Russian Federation); Malikov, M. M., E-mail: mmalikov@oivtran.ru [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2016-11-15

    A physical model of a copper vapor laser pumped by a pulse-periodic inductive (electrodeless) discharge is considered. The feasibility of efficient laser pumping by an inductive discharge and reaching high output parameters comparable to those of conventional copper vapor lasers pumped by a longitudinal electrode discharge is demonstrated. The design and physical features of an inductive copper vapor laser with an annular working volume are discussed.

  13. 2nd Topical Workshop on Laser Technology and Optics Design

    CERN Document Server

    2013-01-01

    Lasers have a variety of applications in particle accelerator operation and will play a key role in the development of future particle accelerators by improving the generation of high brightness electron and exotic ion beams and through increasing the acceleration gradient. Lasers will also make an increasingly important contribution to the characterization of many complex particle beams by means of laser-based beam diagnostics methods. The second LANET topical workshop will address the key aspects of laser technology and optics design relevant to laser application to accelerators. The workshop will cover general optics design, provide an overview of different laser sources and discuss methods to characterize beams in details. Participants will be able to choose from a range of topical areas that go deeper in more specific aspects including tuneable lasers, design of transfer lines, noise sources and their elimination and non-linear optics effects. The format of the workshop will be mainly training-based wit...

  14. PHARAO laser source flight model: Design and performances

    Energy Technology Data Exchange (ETDEWEB)

    Lévèque, T., E-mail: thomas.leveque@cnes.fr; Faure, B.; Esnault, F. X.; Delaroche, C.; Massonnet, D.; Grosjean, O.; Buffe, F.; Torresi, P. [Centre National d’Etudes Spatiales, 18 avenue Edouard Belin, 31400 Toulouse (France); Bomer, T.; Pichon, A.; Béraud, P.; Lelay, J. P.; Thomin, S. [Sodern, 20 Avenue Descartes, 94451 Limeil-Brévannes (France); Laurent, Ph. [LNE-SYRTE, CNRS, UPMC, Observatoire de Paris, 61 avenue de l’Observatoire, 75014 Paris (France)

    2015-03-15

    In this paper, we describe the design and the main performances of the PHARAO laser source flight model. PHARAO is a laser cooled cesium clock specially designed for operation in space and the laser source is one of the main sub-systems. The flight model presented in this work is the first remote-controlled laser system designed for spaceborne cold atom manipulation. The main challenges arise from mechanical compatibility with space constraints, which impose a high level of compactness, a low electric power consumption, a wide range of operating temperature, and a vacuum environment. We describe the main functions of the laser source and give an overview of the main technologies developed for this instrument. We present some results of the qualification process. The characteristics of the laser source flight model, and their impact on the clock performances, have been verified in operational conditions.

  15. Semiconductor laser diodes and the design of a D.C. powered laser diode drive unit

    OpenAIRE

    Cappuccio, Joseph C., Jr.

    1988-01-01

    Approved for public release; distribution is unlimited This thesis addresses the design, development and operational analysis of a D.C. powered semiconductor laser diode drive unit. A laser diode requires an extremely stable power supply since a picosecond spike of current or power supply switching transient could result in permanent damage. The design offers stability and various features for operational protection of the laser diode. The ability to intensity modulate (analog) and pulse m...

  16. Design of a cost-effective laser spot tracker

    Science.gov (United States)

    Artan, Göktuǧ Gencehan; Sari, Hüseyin

    2017-05-01

    One of the most important aspects of guided systems is detection. The most convenient detection in the sense of precision can be achieved with a laser spot tracker. This study deals with a military grade, high performance and cost-effective laser spot tracker for a guided system. The aim is to develop a high field of view system that will detect a laser spot from a distance of 3 kilometers in which the target is designated from 3 kilometers with a laser. The study basically consists of the system design, modeling, producing and the conducting performance tests of the whole system.

  17. High Density GEOSAT/GM Altimeter Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The high density Geosat/GM altimeter data south of 30 S have finally arrived. In addition, ERS-1 has completed more than 6 cycles of its 35-day repeat track. These...

  18. Stability design considerations for mirror support systems in ICF lasers

    International Nuclear Information System (INIS)

    Tietbohl, G.L.; Sommer, S.C.

    1996-10-01

    Some of the major components of laser systems used for Inertial Confinement Fusion (ICF) are the large aperture mirrors which direct the path of the laser. These mirrors are typically supported by systems which consist of mirror mounts, mirror enclosures, superstructures, and foundations. Stability design considerations for the support systems of large aperture mirrors have been developed based on the experience of designing and evaluating similar systems at the Lawrence Livermore National Laboratory (LLNL). Examples of the systems developed at LLNL include Nova, the Petawatt laser, Beamlet, and the National Ignition Facility (NIF). The structural design of support systems of large aperture mirrors has typically been controlled by stability considerations in order for the large laser system to meet its performance requirements for alignment and positioning. This paper will discuss the influence of stability considerations and will provide guidance on the structural design and evaluation of mirror support systems in ICF lasers so that this information can be used on similar systems

  19. Quantum-mechanical designed terahertz laser

    International Nuclear Information System (INIS)

    Benz, A.; Fasching, G.; Unterrainer, K.; Zobl, R.; Andrews, M.A.; Roch, T.; Schrenk, W.; Strasser, G.

    2005-01-01

    Full text: The terahertz-frequency region (1 THz=10 12 Hz) lies between RF-electronics and the photonics. Due to the large demand of coherent sources in this spectral range for applications liKEX medical imaging, chemical sensing and security applications large effort is put into the development of the THz-technology to close the THz-gap. The RF-electronics is able to generate frequencies up to around 0.1 THz, limited by the RC-time-constant of the system. The photonics on the other hand generates frequencies down to around 100 THz, defined by the bandgap of the used semiconducting material. Changing the wavelength requires the selection of a new material or of a new material composition. A new concept for coherent light sources is the quantum cascade laser (QCL), which was developed for the mid-infrared spectral region. The major advantage of the QCL-structure is the possibility to design the emission wavelength by band structure engineering. The wavelength is defined by the energy difference of quantized states in the conduction band. Here, we present a QCL working in the THz spectral region at 3 THz. The design is based on optical transitions between subbands of an AlGaAs/GaAs heterostructure. The thickness of the GaAs and AlGaAs layers were calculated to obtain quantized transitions at the desired THz-frequency. The wavefunctions were optimized to achieve the largest possible matrix element. 271 cascades were grown by molecular beam epitaxy to increase the optical gain and to achieve a waveguide thickness comparable to the THz-wavelength. We report lasing from conventional ridge waveguide and microcavity devices. (author)

  20. Chemical laser exhaust pipe design research

    Science.gov (United States)

    Sun, Yunqiang; Huang, Zhilong; Chen, Zhiqiang; Ren, Zebin; Guo, Longde

    2016-10-01

    In order to weaken the chemical laser exhaust gas influence of the optical transmission, a vent pipe is advised to emissions gas to the outside of the optical transmission area. Based on a variety of exhaust pipe design, a flow field characteristic of the pipe is carried out by numerical simulation and analysis in detail. The research results show that for uniform deflating exhaust pipe, although the pipeline structure is cyclical and convenient for engineering implementation, but there is a phenomenon of air reflows at the pipeline entrance slit which can be deduced from the numerical simulation results. So, this type of pipeline structure does not guarantee seal. For the design scheme of putting the pipeline contract part at the end of the exhaust pipe, or using the method of local area or tail contraction, numerical simulation results show that backflow phenomenon still exists at the pipeline entrance slit. Preliminary analysis indicates that the contraction of pipe would result in higher static pressure near the wall for the low speed flow field, so as to produce counter pressure gradient at the entrance slit. In order to eliminate backflow phenomenon at the pipe entrance slit, concerned with the pipeline type of radial size increase gradually along the flow, flow field property in the pipe is analyzed in detail by numerical simulation methods. Numerical simulation results indicate that there is not reflow phenomenon at entrance slit of the dilated duct. However the cold air inhaled in the slit which makes the temperature of the channel wall is lower than the center temperature. Therefore, this kind of pipeline structure can not only prevent the leak of the gas, but also reduce the wall temperature. In addition, compared with the straight pipe connection way, dilated pipe structure also has periodic structure, which can facilitate system integration installation.

  1. Design and construction of liquid lasers using organic dyes

    International Nuclear Information System (INIS)

    Hariri, Akbar.

    1984-01-01

    Organic dye solution show great promise of obtaining tunable coherent light over the uv, visible and near infrared portion of spectrum. In this paper we describe various pumping schemes of dye molecules. Design, construction and performance of a pulsed dye laser, transversely pumped by a nitrogen laser and wall-ablation flash lamp-pumped dye lasers are the particular examples which are presented in detail

  2. Laser safety in design of near-infrared scanning LIDARs

    Science.gov (United States)

    Zhu, X.; Elgin, D.

    2015-05-01

    3D LIDARs (Light Detection and Ranging) with 1.5μm nanosecond pulse lasers have been increasingly used in different applications. The main reason for their popularity is that these LIDARs have high performance while at the same time can be made eye-safe. Because the laser hazard effect on eyes or skin at this wavelength region (industrial mining applications. We have incorporated the laser safety requirements in the LIDAR design and conducted laser safety analysis for different operational scenarios. While 1.5μm is normally said to be the eye-safe wavelength, in reality a high performance 3D LIDAR needs high pulse energy, small beam size and high pulse repetition frequency (PRF) to achieve long range, high resolution and high density images. The resulting radiant exposure of its stationary beam could be many times higher than the limit for a Class 1 laser device. Without carefully choosing laser and scanning parameters, including field-of-view, scan speed and pattern, a scanning LIDAR can't be eye- or skin-safe based only on its wavelength. This paper discusses the laser safety considerations in the design of eye-safe scanning LIDARs, including laser pulse energy, PRF, beam size and scanning parameters in two basic designs of scanning mechanisms, i.e. galvanometer based scanner and Risley prism based scanner. The laser safety is discussed in terms of device classification, nominal ocular hazard distance (NOHD) and safety glasses optical density (OD).

  3. Mechanical design for a large fusion laser system

    International Nuclear Information System (INIS)

    Hurley, C.A.

    1979-01-01

    The Nova Mechanical Systems Group at LLL is responsible for the design, fabrication, and installation of all laser chain components, for the stable support structure that holds them, and for the beam lines that transport the laser beam to the target system. This paper is an overview of the group's engineering effort, emphasizing new developments

  4. Two-dimensional optimization of free-electron-laser designs

    Science.gov (United States)

    Prosnitz, D.; Haas, R.A.

    1982-05-04

    Off-axis, two-dimensional designs for free electron lasers are described that maintain correspondence of a light beam with a synchronous electron at an optimal transverse radius r > 0 to achieve increased beam trapping efficiency and enhanced laser beam wavefront control so as to decrease optical beam diffraction and other deleterious effects.

  5. Conceptual design of a laser fusion power plant

    International Nuclear Information System (INIS)

    Maniscalco, J.A.; Meier, W.R.; Monsler, M.J.

    1977-01-01

    A conceptual design of a laser fusion power plant is extensively discussed. Recent advances in high gain targets are exploited in the design. A smaller blanket structure is made possible by use of a thick falling region of liquid lithium for a first wall. Major design features of the plant, reactor, and laser systems are described. A parametric analysis of performance and cost vs. design parameters is presented to show feasible design points. A more definitive follow-on conceptual design study is planned

  6. Design of distributed feedback fibre lasers

    DEFF Research Database (Denmark)

    Lauridsen, Vibeke Claudia; Søndergaard, Thomas; Varming, Poul

    1997-01-01

    A numerical model for erbium fibre lasers with Bragg gratings is presented. The model is used to optimize the location of a discrete phase-shift and the phase-shift magnitude for a distributed phase-shift.......A numerical model for erbium fibre lasers with Bragg gratings is presented. The model is used to optimize the location of a discrete phase-shift and the phase-shift magnitude for a distributed phase-shift....

  7. A study of optical design and optimization of laser optics

    Science.gov (United States)

    Tsai, C.-M.; Fang, Yi-Chin

    2013-09-01

    This paper propose a study of optical design of laser beam shaping optics with aspheric surface and application of genetic algorithm (GA) to find the optimal results. Nd: YAG 355 waveband laser flat-top optical system, this study employed the Light tools LDS (least damped square) and the GA of artificial intelligence optimization method to determine the optimal aspheric coefficient and obtain the optimal solution. This study applied the aspheric lens with GA for the flattening of laser beams using collimated laser beam light, aspheric lenses in order to achieve best results.

  8. Design of instrumentation and software for precise laser machining

    Science.gov (United States)

    Wyszyński, D.; Grabowski, Marcin; Lipiec, Piotr

    2017-10-01

    The paper concerns the design of instrumentation and software for precise laser machining. Application of advanced laser beam manipulation instrumentation enables noticeable improvement of cut quality and material loss. This factors have significant impact on process efficiency and cutting edge quality by means of machined part size and shape accuracy, wall taper, material loss reduction (e.g. diamond) and time effectiveness. The goal can be reached by integration of laser drive, observation and optical measurement system, beam manipulation system and five axis mechanical instrumentation with use of advanced tailored software enabling full laser cutting process control and monitoring.

  9. ND:GLASS LASER DESIGN FOR LASER ICF FISSION ENERGY (LIFE)

    International Nuclear Information System (INIS)

    Caird, J.A.; Agrawal, V.; Bayramian, A.; Beach, R.; Britten, J.; Chen, D.; Cross, R.; Ebbers, C.; Erlandson, A.; Feit, M.; Freitas, B.; Ghosh, C.; Haefner, C.; Homoelle, D.; Ladran, T.; Latkowski, J.; Molander, W.; Murray, J.; Rubenchik, S.; Schaffers, K.; Siders, C.W.; Stappaerts, E.; Sutton, S.; Telford, S.; Trenholme, J.; Barty, C.J.

    2008-01-01

    We have developed preliminary conceptual laser system designs for the Laser ICF (Inertial Confinement Fusion) Fission Energy (LIFE) application. Our approach leverages experience in high-energy Nd:glass laser technology developed for the National Ignition Facility (NIF), along with high-energy-class diode-pumped solid-state laser (HEC-DPSSL) technology developed for the DOE's High Average Power Laser (HAPL) Program and embodied in LLNL's Mercury laser system. We present laser system designs suitable for both indirect-drive, hot spot ignition and indirect-drive, fast ignition targets. Main amplifiers for both systems use laser-diode-pumped Nd:glass slabs oriented at Brewster's angle, as in NIF, but the slabs are much thinner to allow for cooling by high-velocity helium gas as in the Mercury laser system. We also describe a plan to mass-produce pump-diode lasers to bring diode costs down to the order of $0.01 per Watt of peak output power, as needed to make the LIFE application economically attractive

  10. ND:GLASS LASER DESIGN FOR LASER ICF FISSION ENERGY (LIFE)

    Energy Technology Data Exchange (ETDEWEB)

    Caird, J A; Agrawal, V; Bayramian, A; Beach, R; Britten, J; Chen, D; Cross, R; Ebbers, C; Erlandson, A; Feit, M; Freitas, B; Ghosh, C; Haefner, C; Homoelle, D; Ladran, T; Latkowski, J; Molander, W; Murray, J; Rubenchik, S; Schaffers, K; Siders, C W; Stappaerts, E; Sutton, S; Telford, S; Trenholme, J; Barty, C J

    2008-10-28

    We have developed preliminary conceptual laser system designs for the Laser ICF (Inertial Confinement Fusion) Fission Energy (LIFE) application. Our approach leverages experience in high-energy Nd:glass laser technology developed for the National Ignition Facility (NIF), along with high-energy-class diode-pumped solid-state laser (HEC-DPSSL) technology developed for the DOE's High Average Power Laser (HAPL) Program and embodied in LLNL's Mercury laser system. We present laser system designs suitable for both indirect-drive, hot spot ignition and indirect-drive, fast ignition targets. Main amplifiers for both systems use laser-diode-pumped Nd:glass slabs oriented at Brewster's angle, as in NIF, but the slabs are much thinner to allow for cooling by high-velocity helium gas as in the Mercury laser system. We also describe a plan to mass-produce pump-diode lasers to bring diode costs down to the order of $0.01 per Watt of peak output power, as needed to make the LIFE application economically attractive.

  11. Liquid-crystal laser optics: design, fabrication, and performance

    International Nuclear Information System (INIS)

    Jacobs, S.D.; Cerqua, K.A.; Marshall, K.L.; Schmid, A.; Guardalben, M.J.; Skerrett, K.J.

    1988-01-01

    We describe the development of laser optics utilizing liquid crystals. Devices discussed constitute passive optical elements for both low-power and high-power laser systems, operating in either the pulsed or cw mode. Designs and fabrication methods are given in detail for wave plates, circular polarizers, optical isolators, laser-blocking notch filters, and soft apertures. Performance data in the visible to near infrared show these devices to be useful alternatives to other technologies based on conventional glasses, crystals, or thin films. The issue of laser damage is examined on the basis of off-line threshold testing and daily use in OMEGA, the 24-beam Nd:glass laser system at the Laboratory for Laser Energetics. Results demonstrate that long-term survivability has been achieved

  12. Conceptual design study for a laser fusion hybrid

    International Nuclear Information System (INIS)

    Maniscalco, J.A.

    1976-01-01

    Lawrence Livermore Laboratory and Bechtel Corporation have been involved in a joint effort to conceptually design a laser fusion hybrid reactor. The design which has evolved is a depleted-uranium fueled fast-fission blanket which produces fissile plutonium and electricity. A major objective of the design study was to evaluate the feasibility of producing fissile fuel with laser fusion. This feasibility evaluation was carried out by analyzing the integrated engineering performance of the complete conceptual design and by identifying the required laser/pellet performance. The performance of the laser fusion hybrid has also been compared to a typical fast breeder reactor. The results show that the laser fusion hybrid produces enough fissile material to fuel more than six light water reactors (LWRs) of equivalent thermal power while operating in a regime which requires an order of magnitude less laser and pellet performance than pure laser fusion. In comparison to a fast breeder reactor the hybrid produces 10 times more fissile fuel. An economic analysis of the design shows that the cost of electricity in a combined hybrid-LWR scenario increases by only 20 to 40 percent when the capital cost of the hybrid ranges from 2 to 3 times more than an LWR

  13. Conceptual design study for a laser fusion hybrid

    International Nuclear Information System (INIS)

    Maniscalco, J.A.

    1976-09-01

    Lawrence Livermore Laboratory and Bechtel Corporation have been involved in a joint effort to conceptually design a laser fusion hybrid reactor. The design which has evolved is a depleted-uranium fueled fast-fission blanket which produces fissile plutonium and electricity. A major objective of the design study was to evaluate the feasibility of producing fissile fuel with laser fusion. This feasibility evaluation was carried out by analyzing the integrated engineering performance of the complete conceptual design and by identifying the required laser/pellet performance. The performance of the laser fusion hybrid has also been compared to a typical fast breeder reactor. The results show that the laser fusion hybrid produces enough fissile material to fuel more than six light water reactors (LWR's) of equivalent thermal power while operating in a regime which requires an order of magnitude less laser and pellet performance than pure laser fusion. In comparison to a fast breeder reactor the hybrid produces 10 times more fissile fuel. An economic analysis of the design shows that the cost of electricity in a combined hybrid-LWR scenario is insensitive to the capital cost of the hybrid, increasing by only 20 to 40 percent when the capital cost of the hybrid ranges from 2 to 3 times more than an LWR

  14. Design Optimization and Fatigue Analysis of Laser Stake Welded Connections

    National Research Council Canada - National Science Library

    Singh, Anshuman; Vel, Senthil S; Caccese, Vincent

    2008-01-01

    This report summanzes research on the design and fatigue analysis of laser-stake welded connections performed at the University of Maine from January 2006 to December 2007 for the Structural Response...

  15. Nd:YAG Laser Firmware Design under RTOS Operation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B. G.; Kim, W. Y.; Park, G. R.; Moon, D. S.; Hong, J. H.; Kim, H. J.; Cho, J. S. [Pusan National University (Korea)

    2000-07-01

    A pulsed Nd:YAG laser is used widely for materials processing and medical instrument. It's very important to control the laser energy density in those fields using a pulsed Nd:YAG laser. A pulse repetition rate and a pulse width are regarded as the most dominant factors to control the energy density of laser beam. In this paper, the alternating charge and discharge system was designed to adjust a pulse repetition rate. This system is controlled by microprocessor and allows to replace an expensive condenser for high frequency to cheap one of low frequency. In addition, The microcontroller monitors the flow of cooling water, short circuit, and miss firing and so on. We designed Nd:YAG laser firmware with smart microcontroller, and want to explain general matters about the firmware from now. (author). 8 refs., 6 figs.

  16. Some aspects of powerful lasers and aspheric lenses design

    International Nuclear Information System (INIS)

    Metz, Jean de

    1976-01-01

    Gigawatt power glass lasers are described. Geometrical, interferometric, coherence and focusing aspects of the beam are measured. Design of disc amplifier is shown with high gain glass. Aspheric lenses are designed and tested for focussing these beams. Experiments of multi-breakdown in gas are done. We get fusion in plasma made by second harmonic frequency of our 1.06 μ beam. Effect of self-focussing on laser beam quality is studied. (author) [fr

  17. Modeling and design of energy concentrating laser weld joints

    Energy Technology Data Exchange (ETDEWEB)

    Milewski, J.O. [Los Alamos National Lab., NM (United States); Sklar, E. [OptiCad Corp., Santa Fe, NM (United States)

    1997-04-01

    The application of lasers for welding and joining has increased steadily over the past decade with the advent of high powered industrial laser systems. Attributes such as high energy density and precise focusing allow high speed processing of precision assemblies. Other characteristics of the process such as poor coupling of energy due to highly reflective materials and instabilities associated with deep penetration keyhole mode welding remain as process limitations and challenges to be overcome. Reflective loss of laser energy impinging on metal surfaces can in some cases exceed ninety five percent, thus making the process extremely inefficient. Enhanced coupling of the laser beam can occur when high energy densities approach the vaporization point of the materials and form a keyhole feature which can trap laser energy and enhance melting and process efficiency. The extreme temperature, pressure and fluid flow dynamics of the keyhole make control of the process difficult in this melting regime. The authors design and model weld joints which through reflective propagation and concentration of the laser beam energy significantly enhance the melting process and weld morphology. A three dimensional computer based geometric optical model is used to describe the key laser parameters and joint geometry. Ray tracing is used to compute the location and intensity of energy absorption within the weld joint. Comparison with experimentation shows good correlation of energy concentration within the model to actual weld profiles. The effect of energy concentration within various joint geometry is described. This method for extending the design of the laser system to include the weld joint allows the evaluation and selection of laser parameters such as lens and focal position for process optimization. The design of narrow gap joints which function as energy concentrators is described. The enhanced laser welding of aluminum without keyhole formation has been demonstrated.

  18. Laser fusion system design study. Final report

    International Nuclear Information System (INIS)

    1975-01-01

    The following studies were completed: (1) The synthesis of a pointing/control system compatible with existing and advanced laser opto-mechanical configurations. (2) Attainment of the required pointing angle, longitudinal focus, and differential pathlength accuracies. (3) Maximum modularization of the sensor and gimbal assemblies to provide the required accuracies at minimum cost. Detailed information is given on each. (MOW)

  19. Compact, Passively Q-Switched Nd:YAG Laser for the MESSENGER Mission to the Planet Mercury

    Science.gov (United States)

    Krebs, Danny J.; Novo-Gradac, Anne-Marie; Li, Steven X.; Lindauer, Steven J.; Afzal, Robert S.; Yu, Antony

    2004-01-01

    A compact, passively Q-switched Nd:YAG laser has been developed for the Mercury Laser Altimeter (MLA) instrument which is an instrument on the MESSENGER mission to the planet Mercury. The laser achieves 5.4 percent efficiency with a near diffraction limited beam. It has passed all space flight environmental tests at system, instrument, and satellite integration. The laser design draws on a heritage of previous laser altimetry missions, specifically ISESAT and Mars Global Surveyor; but incorporates thermal management features unique to the requirements of an orbit of the planet Mercury.

  20. Design and Characterisation of III-V Semiconductor Nanowire Lasers

    Science.gov (United States)

    Saxena, Dhruv

    The development of small, power-efficient lasers underpins many of the technologies that we utilise today. Semiconductor nanowires are promising for miniaturising lasers to even smaller dimensions. III-V semiconductors, such as Gallium Arsenide (GaAs) and Indium Phosphide (InP), are the most widely used materials for optoelectronic devices and so the development of nanowire lasers based on these materials is expected to have technologically significant outcomes. This PhD dissertation presents a comprehensive study of the design of III-V semiconductor nanowire lasers, with bulk and quantum confined active regions. Based on the design, various III-V semiconductor nanowire lasers are demonstrated, namely, GaAs nanowire lasers, GaAs/AlGaAs multi-quantum well (MQW) nanowire lasers and InP nanowire lasers. These nanowire lasers are shown to operate at room temperature, have low thresholds, and lase from different transverse modes. The structural and optoelectronic quality of nanowire lasers are characterised via electron microscopy and photoluminescence spectroscopic techniques. Lasing is characterised in all these devices by optical pumping. The lasing characteristics are analysed by rate equation modelling and the lasing mode(s) in these devices is characterised by threshold gain modelling, polarisation measurements and Fourier plane imaging. Firstly, GaAs nanowire lasers that operate at room temperature are demonstrated. This is achieved by determining the optimal nanowire diameter to reduce threshold gain and by passivating nanowires to improve their quantum efficiency (QE). High-quality surface passivated GaAs nanowires of suitable diameters are grown. The growth procedure is tailored to improve both QE and structural uniformity of nanowires. Room-temperature lasing is demonstrated from individual nanowires and lasing is characterised to be from TM01 mode by threshold gain modelling. To lower threshold even further, nanowire lasers with GaAs/AlGaAs coaxial multi

  1. Design of a femtosecond laser assisted tomographic atom probe

    International Nuclear Information System (INIS)

    Gault, B.; Vurpillot, F.; Vella, A.; Gilbert, M.; Menand, A.; Blavette, D.; Deconihout, B.

    2006-01-01

    A tomographic atom probe (TAP) in which the atoms are field evaporated by means of femtosecond laser pulses has been designed. It is shown that the field evaporation is assisted by the laser field enhanced by the subwavelength dimensions of the specimen without any significant heating of the specimen. In addition, as compared with the conventional TAP, due to the very short duration of laser pulses, no spread in the energy of emitted ions is observed, leading to a very high mass resolution in a straight TAP in a wide angle configuration. At last, laser pulses can be used to bring the intense electric field required for the field evaporation on poor conductive materials such as intrinsic Si at low temperature. In this article, the performance of the laser TAP is described and illustrated through the investigation of metals, oxides, and silicon materials

  2. Review of laser mega joule target area: Design and processes

    International Nuclear Information System (INIS)

    Geitzholz, M.; Lanternier, C.

    2006-01-01

    The Laser Mega Joule (LMJ) target area is currently designed to achieve ignition and significant fusion gain in laboratory. LMJ will be composed of 240 identical large 370 mm * 370 mm square laser beams. These beams will focus 2 mega-joules of energy at the wavelength of 351 nm on the center of an experiment chamber. Design studies for target equipment are well advanced, target chamber and target holder (concrete) works have already begun. A detailed overview of the target area equipment is presented: target chamber, frame, diagnostic inserter manipulator, final optic assembly, dual diagnostic and laser reference, non cryogenic target positioner. Recent technical and architectural choices are detailed including safety transfers and alignment processes (target, laser and diagnostic). All this target equipment allows us to optimize shot chrono-gram, from target metrology to the shot, including calibration process. (authors)

  3. Optical design of high power excimer laser system

    International Nuclear Information System (INIS)

    Zhang Yongsheng; Zhao Jun; Ma Lianying; Yi Aiping; Liu Jingru

    2011-01-01

    Image relay and angular multiplexing,which should be considered together in the design of high power excimer laser system, is reviewed. It's important to select proper illumination setup and laser beam shaping techniques. Given the complex and special angular multiplexing scheme in high power excimer laser systems, some detailed conceptual layout schemes are given in the paper. After a brief description of lens array and reflective telescope objective, which combine the incoming beams to a common focus, a new schematic layout which uses the final targeting optics and one optical delay line array, to realize multiplexing and de-multiplexing simultaneously is first proposed in the paper. (authors)

  4. Design of a laser scanner for a digital mammography system.

    Science.gov (United States)

    Rowlands, J A; Taylor, J E

    1996-05-01

    We have developed a digital readout system for radiographic images using a scanning laser beam. In this system, electrostatic charge images on amorphous selenium (alpha-Se) plates are read out using photo-induced discharge (PID). We discuss the design requirements of a laser scanner for the PID system and describe its construction from commercially available components. The principles demonstrated can be adapted to a variety of digital imaging systems.

  5. Designing, modeling and controlling a novel autonomous laser weeding system

    DEFF Research Database (Denmark)

    Shahrak Nadimi, Esmaeil; Andersson, Kim Johan; Jørgensen, Rasmus Nyholm

    2009-01-01

      Abstract: in this paper, the process of designing and developing a novel laser weeding test setup is explained. The main purpose of designing this system was to simulate the dynamic field conditions of a mobile vehicle capable of targeting weeds. This system consists of a rig containing three...

  6. LASER CUTTING AS AN INNOVATIVE CREATIVITY TOOL IN TEXTILE DESIGN

    Directory of Open Access Journals (Sweden)

    Banu Hatice Gurcum

    2016-12-01

    Full Text Available Innovative technologies have become the most widespread rapid and flexible technique of cutting, welding, printing and coloring in fashion and textile sectors in a very short time. Laser systems as the most common used innovative technology engrave, cut, form, print, shade appropriated formatted drawings and sketches as well as they provide reliable placements for the lay out plans and precision cutting and the production sector rapid and qualified. The practical applications and conveniences that innovative Technologies employ, influence design process, designers can design in a more creative, rapid, precise and effective manner. Although design is a context where technology is effective, the style, mood and the background of the designer is still important. Designers while making innovative studies should take the advantage of the developing technologies in experimental processes and should combine technological opportunities with aesthetics. Textile designer as in all other domains of design, should harmonise with the change and should define his/her style with the innovative Technologies in an innovative manner and renew him/herself all the time. This study aims to classify laser cutting technology applications available in textile and fashion sector as well as to present the laser technology as a means of process, product, material innovation and explains the contributions of laser systems to creativity.

  7. Design of laser source for electricity generation

    International Nuclear Information System (INIS)

    Nasrullah, K.; Mariun, N.; Yeak, J.

    2000-01-01

    New sources of energy are being investigated to meet socioeconomic needs and other trivialities. Systems employing nuclear, thermal, hydro, solar, volcano, tidal and wind power generation techniques already exist. This work describes our attempt to utilize the off-planet charge to store in super electrolytic batteries or super capacitors. The electrostatic charge on clouds can be shifted to earth through a conductive air plasma channel created by appropriate high power Q-switched and mode-locked laser. The pulsed laser may create a conducting path consisting of ionised air particles from earth to some upper atmosphere. An antenna connected to anode of the super cell or positive terminal of the super capacitor will accumulate and store this charge for future use. The cathode of the battery or negative terminal of the super capacitor may be connected to earth to complete the circuit. A large number of such series and parallel units constitute a super battery or super capacitor bank system that can be connected to the national grid through DC to AC converters (DAC) and step-up transformers. According to published data, the lightning strokes may consist of 10 - 40 strokes of 2 - 80 pts duration separated in time by 6 - 530 ms intervals. The total time elapsed in lightning strike may last as long as 1 second. Due to tropical dependence, further detailed work is required to be done on lightning regarding its temporal and spatial profiles to develop a reasonable model to explore transient charging characteristics of storage devices. Experimental work in respect of laser-inducted charge-shifting, transient charging capabilities of super storage batteries or super capacitors is underway. (Author)

  8. Surface laser marking optimization using an experimental design approach

    Science.gov (United States)

    Brihmat-Hamadi, F.; Amara, E. H.; Lavisse, L.; Jouvard, J. M.; Cicala, E.; Kellou, H.

    2017-04-01

    Laser surface marking is performed on a titanium substrate using a pulsed frequency doubled Nd:YAG laser ( λ= 532 nm, τ pulse=5 ns) to process the substrate surface under normal atmospheric conditions. The aim of the work is to investigate, following experimental and statistical approaches, the correlation between the process parameters and the response variables (output), using a Design of Experiment method (DOE): Taguchi methodology and a response surface methodology (RSM). A design is first created using MINTAB program, and then the laser marking process is performed according to the planned design. The response variables; surface roughness and surface reflectance were measured for each sample, and incorporated into the design matrix. The results are then analyzed and the RSM model is developed and verified for predicting the process output for the given set of process parameters values. The analysis shows that the laser beam scanning speed is the most influential operating factor followed by the laser pumping intensity during marking, while the other factors show complex influences on the objective functions.

  9. The design of infrared laser radar for vehicle initiative safety

    Science.gov (United States)

    Gong, Ping; Xu, Xi-ping; Li, Xiao-yu; Li, Tian-zhi; Liu, Yu-long; Wu, Jia-hui

    2013-09-01

    Laser radar for vehicle is mainly used in advanced vehicle on-board active safety systems, such as forward anti-collision systems, active collision warning systems and adaptive cruise control systems, etc. Laser radar for vehicle plays an important role in the improvement of vehicle active safety and the reduction of traffic accidents. The stability of vehicle active anti-collision system in dynamic environment is still one of the most difficult problems to break through nowadays. According to people's driving habit and the existed detecting technique of sensor, combining the infrared laser range and galvanometer scanning technique , design a 3-D infrared laser radar which can be used to assist navigation, obstacle avoidance and the vehicle's speed control for the vehicle initiative safety. The device is fixed to the head of vehicle. Then if an accident happened, the device could give an alarm to remind the driver timely to decelerate or brake down, by which way can people get the purpose of preventing the collision accidents effectively. To accomplish the design, first of all, select the core components. Then apply Zemax to design the transmitting and receiving optical system. Adopt 1550 nm infrared laser transmitter as emission unit in the device, a galvanometer scanning as laser scanning unit and an InGaAs-APD detector as laser echo signal receiving unit. Perform the construction of experimental system using FPGA and ARM as the core controller. The system designed in this paper can not only detect obstacle in front of the vehicle and make the control subsystem to execute command, but also transfer laser data to PC in real time. Lots of experiments using the infrared laser radar prototype are made, and main performance of it is under tested. The results of these experiments show that the imaging speed of the laser radar can reach up to 25 frames per second, the frame resolution of each image can reach 30×30 pixels, the horizontal angle resolution is about 6. 98

  10. Design of a free-electron laser driven by the LBNL laser-plasma-accelerator

    International Nuclear Information System (INIS)

    Schroeder, C.B.; Fawley, W.M.; Montgomery, A.L.; Robinson, K.E.; Gruner, F.; Bakeman, M.; Leemans, W.P.

    2007-01-01

    We discuss the design and current status of a compact free-electron laser (FEL), generating ultra-fast, high-peak flux, VUV pulses driven by a high-current, GeV electron beam from the existing Lawrence Berkeley National Laboratory (LBNL) laser-plasma accelerator, whose active acceleration length is only a few cm. The proposed ultra-fast source would be intrinsically temporally synchronized to the drive laser pulse, enabling pump-probe studies in ultra-fast science with pulse lengths of tens of fs. Owing to the high current ( and 10 kA) of the laser-plasma-accelerated electron beams, saturated output fluxes are potentially greater than 1013 photons/pulse. Devices based both on SASE and high-harmonic generated input seeds, to reduce undulator length and fluctuations, are considered

  11. Multiple-Zone Diffractive Optic Element for Laser Ranging Applications

    Science.gov (United States)

    Ramos-Izquierdo, Luis A.

    2011-01-01

    the manufacturing process, and the same space-compatible DOE substrates (fused silica, sapphire) that are used on standard DOE s could be used for multiple- zone DOE s. DOEs are an elegant and cost-effective optical design option for spacebased laser altimeters that require multiple output laser beams. The use of multiple-zone DOEs would allow for the design and optimization of a laser altimeter instrument required to operate over a large range of target distances, such as those designed to both map and land on a planetary body. In addition to space-based laser altimeters, this technology could find applications in military or commercial unmanned aerial vehicles (UAVs) that fly at an altitude of several kilometers and need to land. It is also conceivable that variations of this approach could be used in land-based applications such as collision avoidance and robotic control of cars, trains, and ships.

  12. Laser beam shaping design based on micromirror array

    Science.gov (United States)

    Fang, Han; Su, Bida; Liu, Jiaguo; Fan, Xiaoli; Jing, Wang

    2017-10-01

    In the practical application of the laser, it is necessary to use the laser beam shaping technology to shape the output beam of laser device to the uniform light intensity distribution. The shaping divergent optical system of compound eye integrator way is composed of beam expanding mirror group and lens array. Its working principle is to expand the output laser to a certain size of caliber, and then divide the beam with lens array into multiple sub beam, where the lens unit of lens array can control the divergence angle of sub beam through the design of focal length, with mutual superposition of the sub beam in far field, to make up for the nonuniformity of beam, so that the radiant exitance on the radiated surface may become uniform. In this paper, we use a reflective microlens array to realize the laser beam shaping. By through of the practical optical path model established, the ray tracing is carried out and the simulation results for single-mode Gaussian beam with noise circumstance is provided. The analysis results show that the laser beam shaping under different inputs can be effectively realized by use of microlens array. All the energy is within the signal window, with a high energy efficiency of more than 90%; The measured surface has a better uniformity, and the uniformity is better than 99.5% at 150m.

  13. Design of optimal laser pulses to control molecular rovibrational ...

    Indian Academy of Sciences (India)

    Optimal control theory in combination with time-dependent quantum dynamics is employed to design laser ... area of quantum computing,22 use of molecular states of various systems ..... frequency) and ωv=0, j=1→v=1, j=0, along with small con- tributions from ... discussed here for three rovibrational excitation pro- cesses.

  14. Optical design for the Laser Astrometric Test of Relativity

    Science.gov (United States)

    Turyshev, Slava G.; Shao, Michael; Nordtvedt, Kenneth L., Jr.

    2004-01-01

    This paper discusses the Laser Astrometric Test of Relativity (LATOR) mission. LATOR is a Michelson-Morley-type experiment designed to test the pure tensor metric nature of gravitation the fundamental postulate of Einstein's theory of general relativity. With its focus on gravity's action on light propagation it complements other tests which rely on the gravitational dynamics of bodies.

  15. Meeting to discuss laser cavity design for photon linear collider ...

    Indian Academy of Sciences (India)

    linear collider – Daresbury, UK, 10 January 2006. ALEXANDER JOHN FINCH ... On 10 January 2006, a meeting to discuss laser cavity design for the photon linear collider was held at the Daresbury .... important to continue making contact with people in fields outside the accelerator community. Few experts at this meeting ...

  16. Laser fusion systems design study. Final technical report

    International Nuclear Information System (INIS)

    1975-06-01

    This study investigated: (1) the formulation and evaluation of an alignment system to accomplish pointing, focusing, centering and translation for the 20-arm SHIVA laser, (2) the formulation and evaluation of concepts for the correction of static phase distortions introduced by the accumulated optical elements in the laser chains, (3) the formulation and evaluation of concepts for the correction of optical path length differences between the arms of the SHIVA system, and (4) the conceptual design of appropriate control system hardware. (U.S.)

  17. Design strategy for terahertz quantum dot cascade lasers.

    Science.gov (United States)

    Burnett, Benjamin A; Williams, Benjamin S

    2016-10-31

    The development of quantum dot cascade lasers has been proposed as a path to obtain terahertz semiconductor lasers that operate at room temperature. The expected benefit is due to the suppression of nonradiative electron-phonon scattering and reduced dephasing that accompanies discretization of the electronic energy spectrum. We present numerical modeling which predicts that simple scaling of conventional quantum well based designs to the quantum dot regime will likely fail due to electrical instability associated with high-field domain formation. A design strategy adapted for terahertz quantum dot cascade lasers is presented which avoids these problems. Counterintuitively, this involves the resonant depopulation of the laser's upper state with the LO-phonon energy. The strategy is tested theoretically using a density matrix model of transport and gain, which predicts sufficient gain for lasing at stable operating points. Finally, the effect of quantum dot size inhomogeneity on the optical lineshape is explored, suggesting that the design concept is robust to a moderate amount of statistical variation.

  18. Design and optimisation of a pulsed CO2 laser for laser ultrasonic applications

    CSIR Research Space (South Africa)

    Forbes, A

    2006-07-01

    Full Text Available at the material surface is detected and converted into a defect map across the aircraft. The design and optimization of a laser system for this application, together with the basic science involved, is reviewed in this paper. This includes the optimization...

  19. Design and optimisation of a pulsed CO2 laser for laser ultrasonics

    CSIR Research Space (South Africa)

    Forbes, A

    2006-02-01

    Full Text Available , resulting in a response at the material surface. This is detected and converted into a defect map across the aircraft. In this paper the authors consider the design and optimisation of a laser system for this application, and cover the basic science...

  20. Inland and Near Shore Water Profiles Derived from the High Altitude Multiple Altimeter Beam Experimental Lidar (MABEL)

    Science.gov (United States)

    Jasinski, Michael F.; Stoll, Jeremy D.; Cook, William B.; Ondrusek, Michael; Stengel, Eric; Brunt, Kelly

    2016-01-01

    The Advanced Topographic Laser Altimeter System (ATLAS) on the Ice, Cloud, and Land Elevation Satellite (ICESat-2) mission is a six beam, low energy, high repetition rate, 532 nm laser transmitter with photon counting detectors. Although designed primarily for detecting height changes in icecaps, sea ice and vegetation, the polar-orbital satellite will observe global surface water during its designed three year life span, including inland water bodies, coasts, and open oceans. In preparation for the mission, an ICESat-2 prototype or the Multiple Altimeter Beam Experimental Lidar (MABEL), was built and flown on high altitude aircraft experiments over a range of inland and near-shore targets. The purpose was to test the ATLAS concept and to provide a database for developing an algorithm that detects along track surface water height and light penetration under a range of atmospheric and water conditions. The current analysis examines the datasets of three MABEL transects observed from 20 km above ground of coastal and inland waters conducted in 2012 and 2013. Transects ranged from about 2 to 12 km in length and included the middle Chesapeake Bay, the near shore Atlantic coast at Virginia Beach, and Lake Mead. Results indicate MABEL's high capability for retrieving surface water height statistics with a mean height precision of approximately 5-7 cm per 100m segment length. Profiles of attenuated subsurface backscatter, characterized using a Signal to Background Ratio written in Log10 base, or LSBR0, were observed over a range of 1.3 to 9.3 meters depending on water clarity and atmospheric background. Results indicate that observable penetration depth, although primarily dependent on water properties, was greatest when solar background rate was low. Near shore bottom reflectance was detected only at the Lake Mead site down to maximum of 10 m under a clear night sky and low turbidity of approximately 1.6 Nephelometric Turbidity Units (NTU). The overall results suggest

  1. Inland and Near-Shore Water Profiles Derived from the High-Altitude Multiple Altimeter Beam Experimental Lidar (MABEL)

    Science.gov (United States)

    Jasinski, Michael F.; Stoll, Jeremy D.; Cook, William B.; Ondrusek, Michael; Stengel, Eric; Brunt, Kelly

    2016-01-01

    The Advanced Topographic Laser Altimeter System (ATLAS) on the Ice, Cloud, and Land Elevation Satellite (ICESat-2) mission is a six beam, low energy, high repetition rate, 532-nanometer laser transmitter with photon counting detectors. Although designed primarily for detecting height changes in ice caps, sea ice, and vegetation, the polar-orbiting satellite will observe global surface water during its designed three-year life span, including inland waterbodies, coasts, and open oceans. In preparation for the mission, an ICESat-2 prototype, the Multiple Altimeter Beam Experimental Lidar (MABEL), was built and flown on high-altitude aircraft experiments over a range of inland and near-shore targets. The purpose was to test the ATLAS concept and to provide a database for developing an algorithm that detects along track surface water height and light penetration under a range of atmospheric and water conditions. The current analysis examines the data sets of three MABEL transects observed from 20 kilometers above ground of coastal and inland waters conducted in 2012 and 2013. Transects ranged from about 2 to 12 kilometers in length and included the middle Chesapeake Bay, the near-shore Atlantic coast at Virginia Beach, and Lake Mead. Results indicate MABEL's high capability for retrieving surface water height statistics with a mean height precision ofapproximately 5-7 centimeters per 100-meter segment length. Profiles of attenuated subsurface backscatter, characterized using a Signal to Background Ratio written in Log10 base, or LSBR (sub 0), were observed over a range of 1.3 to 9.3 meters, depending on water clarity and atmospheric background. Results indicate that observable penetration depth, although primarily dependent on water properties, was greatest when the solar background rate was low. Near-shore bottom reflectance was detected only at the Lake Mead site down to a maximum of 10 meters under a clear night sky and low turbidity of approximately 1

  2. Study and design on USB wireless laser communication system

    Science.gov (United States)

    Wang, Aihua; Zheng, Jiansheng; Ai, Yong

    2004-04-01

    We give the definition of USB wireless laser communication system (WLCS) and the brief introduction to the protocol of USB, the standard of hardware is also given. The paper analyses the hardware and software of USB WLCS. Wireless laser communication part and USB interface circuit part are discussed in detail. We also give the periphery design of the chip AN2131Q, the control circuit to realize the transformation from parallel port to serial bus, and the circuit of laser sending and receiving of laser communication part, which are simply, cheap and workable. And then the four part of software are analyzed as followed. We have consummated the ISR in the firmware frame to develop the periphery device of USB. We have debugged and consummated the 'ezload,' and the GPD of the drivers. Windows application performs functions and schedules the corresponding API functions to let the interface practical and beautiful. The system can realize USB wireless laser communication between computers, which distance is farther than 50 meters, and top speed can be bigger than 8 Mbps. The system is of great practical sense to resolve the issues of high-speed communication among increasing districts without fiber trunk network.

  3. Design and testing of low intensity laser biostimulator

    Directory of Open Access Journals (Sweden)

    Pallikarakis Nicolas E

    2005-01-01

    Full Text Available Abstract Background The non-invasive nature of laser biostimulation has made lasers an attractive alternative in Medical Acupuncture at the last 25 years. However, there is still an uncertainty as to whether they work or their effect is just placebo. Although a plethora of scientific papers published about the topic showing positive clinical results, there is still a lack of objective scientific proofs about the biostimulation effect of lasers in Medical Acupuncture. The objective of this work was to design and build a low cost portable laser device for stimulation of acupuncture points, considered here as small localized biosources (SLB, without stimulating any sensory nerves via shock or heat and to find out a suitable method for objectively evaluating its stimulating effect. The design is aimed for studying SLB potentials provoked by laser stimulus, in search for objective proofs of the biostimulation effect of lasers used in Medical Acupuncture. Methods The proposed biostimulator features two operational modes: program mode and stimulation mode and two output polarization modes: linearly and circularly polarized laser emission. In program mode, different user-defined stimulation protocols can be created and memorized. The laser output can be either continuous or pulse modulated. Each stimulation session consists of a pre-defined number of successive continuous or square pulse modulated sequences of laser emission. The variable parameters of the laser output are: average output power, pulse width, pulse period, and continuous or pulsed sequence duration and repetition period. In stimulation mode the stimulus is automatically applied according to the pre-programmed protocol. The laser source is 30 mW AlGaInP laser diode with an emission wavelength of 685 nm, driven by a highly integrated driver. The optical system designed for beam collimation and polarization change uses single collimating lens with large numerical aperture, linear polarizer

  4. Optical design for increased interaction length in a high gradient dielectric laser accelerator

    OpenAIRE

    Cesar, D.; Maxson, J.; Musumeci, P.; Shen, X.; England, R. J.; Wootton, K. P.

    2018-01-01

    We present a methodology for designing and measuring pulse front tilt in an ultrafast laser for use in dielectric laser acceleration. Previous research into dielectric laser accelerating modules has focused on measuring high accelerating gradients in novel structures, but has done so only for short electron-laser coupling lengths. Here we demonstrate an optical design to extend the laser-electron interaction to 1mm.

  5. Design and construct of a tunable semiconductor laser

    Directory of Open Access Journals (Sweden)

    J. Sabbaghzadeh

    2000-06-01

    Full Text Available   In this paper we explain in detail the design of a semiconductor laser coupled with the reflected beams from a grating. Since the beams reflected are diffracted at different angles, only one component of them can be resonated in the cavity. This technique reduces the output frequency of the laser and increases its stability.   Since this system has various applications in the spectroscopy, gas concentrations, air pollution measurements, investigation of atomic and molecular structure, and so on, system is believed to be simple and accurate. This design is made for the first time in Iran and its reliability has been tested by the measurement of the rubidium atom, and the result is given.

  6. Designing and testing a laser-based vibratory sensor

    Science.gov (United States)

    Nath, G.

    2018-04-01

    Sensor technology has proved its importance, not only in the range of few-meter applications in different fields, but in micro, nano, atomic and sub-atomic-sized objects. The present work describes the designing of a laser-based vibratory sensor using a He-Ne laser as the signal source. The received characteristics of the signal are mainly the frequency and amplitude of the vibration from which the physical parameters such as energy, power and absorption coefficients of the material are determined, which enables us to provide information of the hidden target or object. This laboratory-designed sensor finds application in different local phenomena as well as laboratory practical activity for students.

  7. The design of laser atmosphere transmission characteristic measurement system based on virtual instrument

    Science.gov (United States)

    Zhang, Laixian; Sun, Huayan; Xu, Jiawen

    2010-10-01

    The laser atmosphere transmission characteristic affects the use of laser in engineering greatly. This paper designed a laser atmosphere transmission characteristic measurement system based on LabVIEW software, a product of NI. The system acquires laser spacial distribution by means of controlling NI image acquisition card and CCD through PCI, controls oscillograph to acquire laser time domain distribution through Ethernet and controls power meter to acquire energy of laser through RS-232. It processes the data acquired and analyses the laser atmosphere transmission characteristic using Matlab, which is powerful in data processing, through software interface. It provided a new way to study the laser atmosphere transmission characteristic.

  8. Surface quality finish in laser cutting using Taguchi design

    Czech Academy of Sciences Publication Activity Database

    Sharma, V.; Chattopadhyaya, S.; Hloch, Sergej

    2017-01-01

    Roč. 24, č. 1 (2017), s. 15-19 ISSN 1330-3651 Institutional support: RVO:68145535 Keywords : cutting speed * factorial design * laser pulse width * orthogonal array * pulse repetition rate (PRR) or pulse frequency Subject RIV: JQ - Machines ; Tools OBOR OECD: Mechanical engineering Impact factor: 0.723, year: 2016 http://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=257818

  9. Design of remote laser-induced fluorescence system's acquisition circuit

    Science.gov (United States)

    Wang, Guoqing; Lou, Yue; Wang, Ran; Yan, Debao; Li, Xin; Zhao, Xin; Chen, Dong; Zhao, Qi

    2017-10-01

    Laser-induced fluorescence system(LIfS) has been found its significant application in identifying one kind of substance from another by its properties even it's thimbleful, and becomes useful in plenty of fields. Many superior works have reported LIfS' theoretical analysis , designs and uses. However, the usual LIPS is always constructed in labs to detect matter quite closely, for the system using low-power laser as excitation source and charge coupled device (CCD) as detector. Promoting the detectivity of LIfS is of much concern to spread its application. Here, we take a high-energy narrow-pulse laser instead of commonly used continuous wave laser to operate sample, thus we can get strong fluorescent. Besides, photomultiplier (PMT) with high sensitivity is adopted in our system to detect extremely weak fluorescence after a long flight time from the sample to the detector. Another advantage in our system, as the fluorescence collected into spectroscopy, multiple wavelengths of light can be converted to the corresponding electrical signals with the linear array multichannel PMT. Therefore, at the cost of high-powered incentive and high-sensitive detector, a remote LIFS is get. In order to run this system, it is of importance to turn light signal to digital signal which can be processed by computer. The pulse width of fluorescence is deeply associated with excitation laser, at the nanosecond(ns) level, which has a high demand for acquisition circuit. We design an acquisition circuit including, I/V conversion circuit, amplifying circuit and peak-holding circuit. The simulation of circuit shows that peak-holding circuit can be one effective approach to reducing difficulty of acquisition circuit.

  10. Mapping the Topography of Mercury with MESSENGER Laser Altimetry

    Science.gov (United States)

    Sun, Xiaoli; Cavanaugh, John F.; Neumann, Gregory A.; Smith, David E..; Zubor, Maria T.

    2012-01-01

    The Mercury Laser Altimeter onboard MESSENGER involves unique design elements that deal with the challenges of being in orbit around Mercury. The Mercury Laser Altimeter (MLA) is one of seven instruments on NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. MESSENGER was launched on 3 August 2004, and entered into orbit about Mercury on 18 March 2011 after a journey through the inner solar system. This involved six planetary flybys, including three of Mercury. MLA is designed to map the topography and landforms of Mercury's surface. It also measures the planet's forced libration (motion about the spin axis), which helps constrain the state of the core. The first science measurements from orbit taken with MLA were made on 29 March 2011 and continue to date. MLA had accumulated about 8.3 million laser ranging measurements to Mercury's surface, as of 31 July 2012, i.e., over six Mercury years (528 Earth days). Although MLA is the third planetary lidar built at the NASA Goddard Space Flight Center (GSFC), MLA must endure a much harsher thermal environment near Mercury than the previous instruments on Mars and Earth satellites. The design of MLA was derived in part from that of the Mars Orbiter Laser Altimeter on Mars Global Surveyor. However, MLA must range over greater distances and often in off-nadir directions from a highly eccentric orbit. In MLA we use a single-mode diode-pumped Nd:YAG (neodymium-doped yttrium aluminum garnet) laser that is highly collimated to maintain a small footprint on the planet. The receiver has both a narrow field of view and a narrow spectral bandwidth to minimize the amount of background light detected from the sunlit hemisphere of Mercury. We achieve the highest possible receiver sensitivity by employing the minimum receiver detection threshold.

  11. Precise topography assessment of Lop Nur Lake Basin using GLAS altimeter

    International Nuclear Information System (INIS)

    Wang, Longfei; Gong, Huaze; Shao, Yun

    2014-01-01

    Lop Nur is a dried-up salt lake lying in the eastern part of Tarim basin, which used to be the second largest lagon in China. The ''ear'' rings in Lop Nur attract many interests and are regarded as the lake shorelines during its recession. The topography of the lake basin is important in understanding the formation of the ''ear'' rings. In this paper, elevation data along three transects obtained from laser altimeter were taken as the basic material of the topography in Lop Nur. Elevation data of laser altimeter show great consistency between adjacent passes. Orthometric height (OH) derived from altimetry data and the geoid model are used to analyze the elevation characteristic along ''ear'' rings. The result shows the ''ear'' rings are basically identical in elevation, supporting the statement that ''ear'' rings are former lake shorelines. A discrepancy of approximately 1 meter in OH is observed on the same ''ear'' ring, lower in the north and higher in the south, which is found for the first time. Possible explanations could be deformation of ground surface due to earthquake or tectonic movement after the ''ear'' rings are formed, or tilt of water surface due to wind stress or lake current during the formation of the rings

  12. Combined raman spectrometer/laser-induced breakdown spectrometer design concept

    Science.gov (United States)

    Bazalgette Courrèges-Lacoste, Gregory; Ahlers, Berit; Boslooper, Erik; Rull-Perez, Fernando; Maurice, Sylvestre

    2017-11-01

    Amongst the different instruments that have been preselected to be on-board the Pasteur payload on ExoMars is the Raman/ Laser Induced Breakdown Spectroscopy (LIBS) instrument. Raman spectroscopy and LIBS will be integrated into a single instrument sharing many hardware commonalities. An international team under the lead of TNO has been gathered to produce a design concept for a combined Raman Spectrometer/ LIBS Elegant Bread-Board (EBB). The instrument is based on a specifically designed extremely compact spectrometer with high resolution over a large wavelength range, suitable for both Raman spectroscopy and LIBS measurements. Low mass, size and resources are the main drivers of the instrument's design concept. The proposed design concept, realization and testing programme for the combined Raman/ LIBS EBB is presented as well as background information on Raman and LIBS.

  13. Effects of surface roughness on sea ice freeboard retrieval with an Airborne Ku-Band SAR radar altimeter

    DEFF Research Database (Denmark)

    Hendricks, Stefan; Stenseng, Lars; Helm, Veit

    2010-01-01

    to investigate sea ice volume changes on an Arctic wide scale. Freeboard retrieval requires precise radar range measurements to the ice surface, therefore we investigate the penetration of the Ku-Band radar waves into the overlying snow cover as well as the effects of sub-footprint-scale surface roughness using...... airborne radar and laser altimeters. We find regional variable penetration of the radar signal at late spring conditions, where the difference of the radar and the reference laser range measurement never agrees with the expected snow thickness. In addition, a rough surface can lead to biases...

  14. Ultraviolet Free Electron Laser Facility preliminary design report

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Zvi, I. (ed.)

    1993-02-01

    This document, the Preliminary Design Report (PDR) for the Brookhaven Ultraviolet Free Electron Laser (UV FEL) facility, describes all the elements of a facility proposed to meet the needs of a research community which requires ultraviolet sources not currently available as laboratory based lasers. Further, for these experiments, the requisite properties are not extant in either the existing second or upcoming third generation synchrotron light sources. This document is the result of our effort at BNL to identify potential users, determine the requirements of their experiments, and to design a facility which can not only satisfy the existing need, but have adequate flexibility for possible future extensions as need dictates and as evolving technology allows. The PDR is comprised of three volumes. In this, the first volume, background for the development of the proposal is given, including descriptions of the UV FEL facility, and representative examples of the science it was designed to perform. Discussion of the limitations and potential directions for growth are also included. A detailed description of the facility design is then provided, which addresses the accelerator, optical, and experimental systems. Information regarding the conventional construction for the facility is contained in an addendum to volume one (IA).

  15. Ultraviolet Free Electron Laser Facility preliminary design report

    International Nuclear Information System (INIS)

    Ben-Zvi, I.

    1993-02-01

    This document, the Preliminary Design Report (PDR) for the Brookhaven Ultraviolet Free Electron Laser (UV FEL) facility, describes all the elements of a facility proposed to meet the needs of a research community which requires ultraviolet sources not currently available as laboratory based lasers. Further, for these experiments, the requisite properties are not extant in either the existing second or upcoming third generation synchrotron light sources. This document is the result of our effort at BNL to identify potential users, determine the requirements of their experiments, and to design a facility which can not only satisfy the existing need, but have adequate flexibility for possible future extensions as need dictates and as evolving technology allows. The PDR is comprised of three volumes. In this, the first volume, background for the development of the proposal is given, including descriptions of the UV FEL facility, and representative examples of the science it was designed to perform. Discussion of the limitations and potential directions for growth are also included. A detailed description of the facility design is then provided, which addresses the accelerator, optical, and experimental systems. Information regarding the conventional construction for the facility is contained in an addendum to volume one (IA)

  16. Double-shell target designs for the Los Alamos Scientific Laboratory eight-beam laser system

    International Nuclear Information System (INIS)

    Kindel, J.M.; Stroscio, M.A.

    1978-03-01

    We investigate two double-pusher laser fusion targets, one that incorporates an outer exploding pusher shell and another that uses velocity multiplication. Specific designs are presented for the Los Alamos Scientific Laboratory Eight-Beam Laser System

  17. Design of all solid state tunable single-mode Ti: sapphire laser for nuclear industry

    International Nuclear Information System (INIS)

    Lee, J.H.; Nam, S.M.; Lee, Y.J.; Lee, J.M.; Horn, Roland E.; Wendt, Klaus

    1999-01-01

    We designed a Ti:Sapphire laser pumped by a diode laser pumped solid state laser (DPSSL). The DPSSL was intra-cavity frequency doubled and it had 20 W output power. The Ti:Sapphire laser was designed for single longitudinal mode lasing. For single mode lasing, the laser used several solid etalons. We simulated temporal evolution of the laser pulse and single pass amplification rate of the photons in each modes from rate equations. From the result, we found that single mode lasing is viable in this cavity

  18. Polymers designed for laser ablation-influence of photochemical properties

    International Nuclear Information System (INIS)

    Lippert, T.; Dickinson, J.T.; Hauer, M.; Kopitkovas, G.; Langford, S.C.; Masuhara, H.; Nuyken, O.; Robert, J.; Salmio, H.; Tada, T.; Tomita, K.; Wokaun, A.

    2002-01-01

    The ablation characteristics of various polymers were studied at low and high fluences. The polymers can be divided into three groups, i.e. polymers containing triazene and ester groups, the same polymers without the triazene group, and polyimide as reference polymer. At high fluences similar ablation parameters, i.e. etch rates and effective absorption coefficients, were obtained for all polymers. The main difference is the absence of carbon deposits for the designed polymers. At low fluences (at 308 nm) very pronounced differences are detected. The polymers containing the photochemically most active group (triazene) exhibit the lowest threshold of ablation (as low as 25 mJ cm -2 ) and the highest etch rates (up to 3 μm/pulse), followed by the designed polyesters and then polyimide. The laser-induced decomposition of the designed polymers was studied by nanosecond-interferometry. Only the triazene-polymer reveals etching without any sign of surface swelling, which is observed for all other polymers. The etching of the triazene-polymer starts and ends with the laser pulse, clearly indicating photochemical etching. The triazene-polymer was also studied by time-of-flight mass spectrometry (TOF-MS). The intensities of the ablation fragments show pronounced differences between irradiation at the absorption band of the triazene group (308 nm) and irradiation at a shorter wavelength (248 nm)

  19. Design challenges for matrix assisted pulsed laser evaporation and infrared resonant laser evaporation equipment

    Science.gov (United States)

    Greer, James A.

    2011-11-01

    Since the development of the Matrix Assisted Pulsed Laser Evaporation (MAPLE) process by the Naval Research Laboratory (NRL) in the late 1990s, MAPLE has become an active area of research for the deposition of a variety of polymer, biological, and organic thin films. As is often the case with advancements in thin-film deposition techniques new technology sometimes evolves by making minor or major adjustments to existing deposition process equipment and techniques. This is usually the quickest and least expensive way to try out new ideas and to "push the envelope" in order to obtain new and unique scientific results as quickly as possible. This process of "tweaking" current equipment usually works to some degree, but once the new process is further refined overall designs for a new deposition tool based on the critical attributes of the new process typically help capitalize more fully on the all the salient features of the new and improved process. This certainly has been true for the MAPLE process. In fact the first MAPLE experiments the polymer/solvent matrix was mixed and poured into a copper holder held at LN2 temperature on a laboratory counter top. The holder was then quickly placed onto a LN2 cooled reservoir in a vacuum deposition chamber and placed in a vertical position on a LN2 cooled stage and pumped down as quickly as possible. If the sample was not placed into the chamber quickly enough the frozen matrix would melt and drip into the bottom of the chamber onto the chambers main gate valve making a bit of a mess. However, skilled and motivated scientists usually worked quickly enough to make this process work most of the time. The initial results from these experiments were encouraging and led to several publications which sparked considerable interest in this newly developed technique Clearly this approach provided the vision that MAPLE was a viable deposition process, but the equipment was not optimal for conducting MAPLE experiments on a regular basis

  20. Design of High Precise Focusing System in Laser Direct Writer

    International Nuclear Information System (INIS)

    Liang, Y Y; Tian, F; Luo, J B; Yang, G G

    2006-01-01

    In order to improve the accuracy and efficiency of fabricating lines with laser pattern generator, a novel focusing system was designed. Focusing system is based on optical off-axis detection principle. The detector is a two-quadrant photocell and the defocus signal is constructed by division. Focusing system has the character of second-order system with overdamp. The new embedded PID controller improves the performance of focusing system and upgrades the closed-loop precision to 0.2 μm. Furthermore focusing system has the fabrication capabilities for alterable-width lines under various defocus amount

  1. Design and construction of wave guide CO2 laser

    International Nuclear Information System (INIS)

    Al-Ali, M.S.

    1989-01-01

    This thesis describes the design, construction and operation of a countinous wave (CW) CO2 waveguide laser with axial gas flow in which the multi-electrode technique was used to achieve uniform volume of ionized gas using two and four pairs of electrodes. Resonators of lengths ( 26 - 47.5 ) cm with inside diameter ( 3 - 4 ) mm were used with discharge taking place between four pairs of electordes 8.25 cm long each, in axial direction of the tube. The avearge flow at the tube outlet was ( 5 - 6.5 ) L/min at different gas pressures. ( 4 tabs., 74 figs., 58 refs. )

  2. Conceptual design of laser fusion reactor, SENRI-I - 1. concept and system design

    International Nuclear Information System (INIS)

    Ido, S.; Naki, S.; Norimatsu, T.

    1981-01-01

    Design features of a laser fusion reactor concept SENRI-I and new concepts are reviewed and discussed. The unique feature is the utilization of a magnetic field to guide and control the inner liquid Li flow. Basic requirements and typical parameters used in the design are presented. Items to be discussed are constitution of the system, performance of liquid Li flow, neutronics, thermo-electric cycle, fuel cycle and new concepts

  3. A unified modeling approach for physical experiment design and optimization in laser driven inertial confinement fusion

    Energy Technology Data Exchange (ETDEWEB)

    Li, Haiyan [Mechatronics Engineering School of Guangdong University of Technology, Guangzhou 510006 (China); Huang, Yunbao, E-mail: Huangyblhy@gmail.com [Mechatronics Engineering School of Guangdong University of Technology, Guangzhou 510006 (China); Jiang, Shaoen, E-mail: Jiangshn@vip.sina.com [Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China); Jing, Longfei, E-mail: scmyking_2008@163.com [Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China); Tianxuan, Huang; Ding, Yongkun [Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China)

    2015-11-15

    Highlights: • A unified modeling approach for physical experiment design is presented. • Any laser facility can be flexibly defined and included with two scripts. • Complex targets and laser beams can be parametrically modeled for optimization. • Automatically mapping of laser beam energy facilitates targets shape optimization. - Abstract: Physical experiment design and optimization is very essential for laser driven inertial confinement fusion due to the high cost of each shot. However, only limited experiments with simple structure or shape on several laser facilities can be designed and evaluated in available codes, and targets are usually defined by programming, which may lead to it difficult for complex shape target design and optimization on arbitrary laser facilities. A unified modeling approach for physical experiment design and optimization on any laser facilities is presented in this paper. Its core idea includes: (1) any laser facility can be flexibly defined and included with two scripts, (2) complex shape targets and laser beams can be parametrically modeled based on features, (3) an automatically mapping scheme of laser beam energy onto discrete mesh elements of targets enable targets or laser beams be optimized without any additional interactive modeling or programming, and (4) significant computation algorithms are additionally presented to efficiently evaluate radiation symmetry on the target. Finally, examples are demonstrated to validate the significance of such unified modeling approach for physical experiments design and optimization in laser driven inertial confinement fusion.

  4. Optimum design of a multi-stage dye-laser amplifier pumped with Cu-vapor lasers

    International Nuclear Information System (INIS)

    Maeda, Mitsuo; Uchiumi, Michihiro

    1990-01-01

    A numerical simulation code, based on the one-dimensional photon transport equation, was developed and analyzed to evaluate the performances of Rhodamine 6G dye laser amplifiers pumped with Cu-vapor lasers. The upper singlet-state absorption played an important role to determine the efficiency. The simulation code was applied to optimize a multi-stage amplifier system with a pulsed or a CW dye-laser oscillator. The analytical results gave a useful guideline to design a high-power pulsed dye-laser system for atomic uranium enrichment. (author)

  5. Design process for NIF laser alignment and beam diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Grey, A., LLNL

    1998-06-09

    In a controller for an adaptive optic system designed to correct phase aberrations in a high power laser, the wavefront sensor is a discrete Hartmann-Shack design. It uses an army of lenslets (like a fly` s eye) to focus the laser into 77 spots on a CCD camera. Average local tilt of the wavefront across each lenslet changes the position of its focal spot. The system requires 0.1 pixel accuracy in determining the focal spot location. We determine a small area around each spot` s previous location. Within this area, we calculate the centroid of the light intensity in x and y. This calculation fails if the spot regions overlap. Especially during initial acquisition of a highly distorted beam, distinguishing overlapping spots is difficult. However, low resolution analysis of the overlapping spots allows the system to estimate their positions. With this estimate, it can use the deformable mirror to correct the beam enough so we can detect the spots using conventional image processing.

  6. Design of high power solid-state pulsed laser resonators

    International Nuclear Information System (INIS)

    Narro, R.; Ponce, L.; Arronte, M.

    2009-01-01

    Methods and configurations for the design of high power solid-state pulsed laser resonators, operating in free running, are presented. For fundamental mode high power resonators, a method is proposed for the design of a resonator with joined stability zones. In the case of multimode resonators, two configurations are introduced for maximizing the laser overall efficiency due to the compensation of the astigmatism induced by the excitation. The first configuration consists in a triangular ring resonator. The results for this configuration are discussed theoretically, showing that it is possible to compensate the astigmatism of the thermal lens virtually in a 100%; however this is only possible for a specific pumping power. The second configuration proposes a dual-active medium resonator, rotated 90 degree one from the other around the optical axis, where each active medium acts as an astigmatic lens of the same dioptric power. The reliability of this configuration is corroborated experimentally using a Nd:YAG dual-active medium resonator. It is found that in the pumping power range where the astigmatism compensation is possible, the overall efficiency is constant, even when increasing the excitation power with the consequent increase of the thermal lens dioptric power. (Author)

  7. An optimized design of rectangle pumping cell for nuclear reactor pumped laser

    International Nuclear Information System (INIS)

    Wan, J.-S.; Chen, L.-X.; Zhao, Z.-M.; Pan, X.-B.; Jing, C.-Y.; Zhao, X.-Q.; Liu, F.-H.

    2003-01-01

    Basing on our research of energy deposition in RPL (Reactor Pumped Laser) pumping cell and the laser power efficiency, a RPL test device on Pulsed Reactor has been designed. In addition, the laser beam power of the RPL test device is estimated in the paper. (author)

  8. 77 FR 21834 - Airborne Radar Altimeter Equipment (For Air Carrier Aircraft)

    Science.gov (United States)

    2012-04-11

    ... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Airborne Radar Altimeter Equipment... Technical Standard Order (TSO)-C67, Airborne Radar Altimeter Equipment (For Air Carrier Aircraft). SUMMARY: This is a confirmation notice of the cancellation of TSO-C67, Airborne Radar Altimeter Equipment (For...

  9. 77 FR 3323 - Airborne Radar Altimeter Equipment (For Air Carrier Aircraft)

    Science.gov (United States)

    2012-01-23

    ... DEPARTMENT OF TRANSPORTATION Federal Aviation Administration Airborne Radar Altimeter Equipment... to cancel Technical Standard Order (TSO)-C67, Airborne Radar Altimeter Equipment (For Air Carrier Aircraft). SUMMARY: This notice announces the FAA's intent to cancel TSO-C67, Airborne Radar Altimeter...

  10. Design of fiber optic probes for laser light scattering

    Science.gov (United States)

    Dhadwal, Harbans S.; Chu, Benjamin

    1989-01-01

    A quantitative analysis is presented of the role of optical fibers in laser light scattering. Design of a general fiber optic/microlens probe by means of ray tracing is described. Several different geometries employing an optical fiber of the type used in lightwave communications and a graded index microlens are considered. Experimental results using a nonimaging fiber optic detector probe show that due to geometrical limitations of single mode fibers, a probe using a multimode optical fiber has better performance, for both static and dynamic measurements of the scattered light intensity, compared with a probe using a single mode fiber. Fiber optic detector probes are shown to be more efficient at data collection when compared with conventional approaches to measurements of the scattered laser light. Integration of fiber optic detector probes into a fiber optic spectrometer offers considerable miniaturization of conventional light scattering spectrometers, which can be made arbitrarily small. In addition static and dynamic measurements of scattered light can be made within the scattering cell and consequently very close to the scattering center.

  11. Army Solid State Laser Program: Design, Operation, and Mission Analysis for a Heat-Capacity Laser

    International Nuclear Information System (INIS)

    Dane, C B; Flath, L; Rotter, M; Fochs, S; Brase, J; Bretney, K

    2001-01-01

    Solid-state lasers have held great promise for the generation of high-average-power, high-quality output beams for a number of decades. However, the inherent difficulty of scaling the active solid-state gain media while continuing to provide efficient cooling has limited demonstrated powers to 10X the diffraction limit. Challenges posed by optical distortions and depolarization arising from internal temperature gradients in the gain medium of a continuously cooled system are only increased for laser designs that would attempt to deliver the high average power in the form of high energy pulses (>25J) from a single coherent optical aperture. Although demonstrated phase-locking of multiple laser apertures may hold significant promise for the future scaling of solid-state laser systems,1 the continuing need for additional technical development and innovation coupled with the anticipated complexity of these systems effectively limits this approach for near-term multi-kW laser operation outside of a laboratory setting. We have developed and demonstrated a new operational mode for solid-state laser systems in which the cooling of the gain medium is separated in time from the lasing cycle. In ''heat-capacity'' operation, no cooling takes place during lasing. The gain medium is pumped very uniformly and the waste heat from the excitation process is stored in the solid-state gain medium. By depositing the heat on time scales that are short compared to thermal diffusion across the optical aperture, very high average power operation is possible while maintaining low optical distortions. After a lasing cycle, aggressive cooling can then take place in the absence of lasing, limited only by the fracture limit of the solid-state medium. This mode of operation is ideally suited for applications that require 1-30s engagements at very high average power. If necessary, multiple laser apertures can provide continuous operation. Land Combat mission analysis of a stressing air defense

  12. Advanced specialty fiber designs for high power fiber lasers

    Science.gov (United States)

    Gu, Guancheng

    The output power of fiber lasers has increased rapidly over the last decade. There are two major limiting factors, namely nonlinear effects and transverse mode instability, prohibiting the power scaling capability of fiber lasers. The nonlinear effects, originating from high optical intensity, primarily limit the peak power scaling. The mode instability, on the other hand, arises from quantum-defect driven heating, causing undesired mode coupling once the power exceeds the threshold and degradation of beam quality. The mode instability has now become the bottleneck for average output power scaling of fiber lasers. Mode area scaling is the most effective way to mitigate nonlinear effects. However, the use of large mode area may increase the tendency to support multiple modes in the core, resulting in lower mode instability threshold. Therefore, it is critical to maintain single mode operation in a large mode area fiber. Sufficient higher order mode suppression can lead to effective single-transverse-mode propagation. In this dissertation, we explore the feasibility of using specialty fiber to construct high power fiber lasers with robust single-mode output. The first type of fiber discussed is the resonantly-enhanced leakage channel fiber. Coherent reflection at the fiber outer boundary can lead to additional confinement especially for highly leaky HOM, leading to lower HOM losses than what are predicted by conventional finite element mothod mode solver considering infinite cladding. In this work, we conducted careful measurements of HOM losses in two leakage channel fibers (LCF) with circular and rounded hexagonal boundary shapes respectively. Impact on HOM losses from coiling, fiber boundary shapes and coating indexes were studied in comparison to simulations. This work demonstrates the limit of the simulation method commonly used in the large-mode-area fiber designs and the need for an improved approach. More importantly, this work also demonstrates that a

  13. Conceptual design of industrial free electron laser using superconducting accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Saldin, E.L.; Schneidmiller, E.A.; Ulyanov, Yu.N. [Automatic Systems Corporation, Samara (Russian Federation)] [and others

    1995-12-31

    Paper presents conceptual design of free electron laser (FEL) complex for industrial applications. The FEL complex consists of three. FEL oscillators with the optical output spanning the infrared (IR) and ultraviolet (UV) wave-lengths ({lambda} = 0.3...20 {mu}m) and with the average output power 10 - 20 kW. The driving beam for the FELs is produced by a superconducting accelerator. The electron beam is transported to the FELs via three beam lines (125 MeV and 2 x 250 MeV). Peculiar feature of the proposed complex is a high efficiency of the. FEL oscillators, up to 20 %. This becomes possible due to the use of quasi-continuous electron beam and the use of the time-dependent undulator tapering.

  14. Designing Light Beam Transmittance Measuring Tool Using a Laser Pointer

    Science.gov (United States)

    Nuroso, H.; Kurniawan, W.; Marwoto, P.

    2016-08-01

    A simple instrument used for measuring light beam transmittance percentage made of window film has been developed. The instrument uses a laser pointer of 405 nm and 650 nm ±10% as a light source. Its accuracy approaches 80%. Transmittance data was found by comparing the light beam before and after passing the window film. The light intensity measuring unit was deleted by splitting the light source into two beams through a beam splitter. The light beam was changed into resistance by a NORP12 LDR sensor designed at a circuit of voltage divider rule of Khirchoff's laws. This conversion system will produce light beam intensity received by the sensor to become an equal voltage. This voltage will, then, be presented on the computer screen in the form of a real time graph via a 2.0 USB data transfer.

  15. Design Optimization and Fatigue Analysis of Laser Stake Welded Connections

    Science.gov (United States)

    2008-06-01

    is ultimately envisioned that laser welding will be as common in the shipyard as other processes such -- as MIG, TIG and SMAW. Laser stake- welding of...input from conventional welding techniques can be detrimental to the polymer matrix composite material. In comparison, the laser welding process allows...more discrete frequencies. In the laser welding process , the photons are targeted on the work piece surface which needs to be welded . Highly

  16. A Multi-Wavelength IR Laser for Space Applications

    Science.gov (United States)

    Li, Steven X.; Yu, Anthony W.; Sun, Xiaoli; Fahey, Molly E.; Numata, Kenji; Krainak, Michael A.

    2017-01-01

    We present a laser technology development with space flight heritage to generate laser wavelengths in the near- to mid-infrared (NIR to MIR) for space lidar applications. Integrating an optical parametric crystal to the LOLA (Lunar Orbiter Laser Altimeter) laser transmitter design affords selective laser wavelengths from NIR to MIR that are not easily obtainable from traditional diode pumped solid-state lasers. By replacing the output coupler of the LOLA laser with a properly designed parametric crystal, we successfully demonstrated a monolithic intra-cavity optical parametric oscillator (iOPO) laser based on all high technology readiness level (TRL) subsystems and components. Several desired wavelengths have been generated including 2.1 microns, 2.7 microns and 3.4 microns. This laser can also be used in trace-gas remote sensing, as many molecules possess their unique vibrational transitions in NIR to MIR wavelength region, as well as in time-of-flight mass spectrometer where desorption of samples using MIR laser wavelengths have been successfully demonstrated.

  17. Conceptual design of a laser-plasma accelerator driven free-electron laser demonstration experiment

    International Nuclear Information System (INIS)

    Seggebrock, Thorben

    2015-01-01

    Up to now, short-wavelength free-electron lasers (FEL) have been systems on the scale of hundreds of meters up to multiple kilometers. Due to the advancements in laser-plasma acceleration in the recent years, these accelerators have become a promising candidate for driving a fifth-generation synchrotron light source - a lab-scale free-electron laser. So far, demonstration experiments have been hindered by the broad energy spread typical for this type of accelerator. This thesis addresses the most important challenges of the conceptual design for a first lab-scale FEL demonstration experiment using analytical considerations as well as simulations. The broad energy spread reduces the FEL performance directly by weakening the microbunching and indirectly via chromatic emittance growth, caused by the focusing system. Both issues can be mitigated by decompressing the electron bunch in a magnetic chicane, resulting in a sorting by energies. This reduces the local energy spread as well as the local chromatic emittance growth and also lowers performance degradations caused by the short bunch length. Moreover, the energy dependent focus position leads to a focus motion within the bunch, which can be synchronized with the radiation pulse, maximizing the current density in the interaction region. This concept is termed chromatic focus matching. A comparison shows the advantages of the longitudinal decompression concept compared to the alternative approach of transverse dispersion. When using typical laser-plasma based electron bunches, coherent synchrotron radiation and space-charge contribute in equal measure to the emittance growth during decompression. It is shown that a chicane for this purpose must not be as weak and long as affordable to reduce coherent synchrotron radiation, but that an intermediate length is required. Furthermore, the interplay of the individual concepts and components is assessed in a start-to-end simulation, confirming the feasibility of the

  18. Conceptual design of a laser-plasma accelerator driven free-electron laser demonstration experiment

    Energy Technology Data Exchange (ETDEWEB)

    Seggebrock, Thorben

    2015-07-08

    Up to now, short-wavelength free-electron lasers (FEL) have been systems on the scale of hundreds of meters up to multiple kilometers. Due to the advancements in laser-plasma acceleration in the recent years, these accelerators have become a promising candidate for driving a fifth-generation synchrotron light source - a lab-scale free-electron laser. So far, demonstration experiments have been hindered by the broad energy spread typical for this type of accelerator. This thesis addresses the most important challenges of the conceptual design for a first lab-scale FEL demonstration experiment using analytical considerations as well as simulations. The broad energy spread reduces the FEL performance directly by weakening the microbunching and indirectly via chromatic emittance growth, caused by the focusing system. Both issues can be mitigated by decompressing the electron bunch in a magnetic chicane, resulting in a sorting by energies. This reduces the local energy spread as well as the local chromatic emittance growth and also lowers performance degradations caused by the short bunch length. Moreover, the energy dependent focus position leads to a focus motion within the bunch, which can be synchronized with the radiation pulse, maximizing the current density in the interaction region. This concept is termed chromatic focus matching. A comparison shows the advantages of the longitudinal decompression concept compared to the alternative approach of transverse dispersion. When using typical laser-plasma based electron bunches, coherent synchrotron radiation and space-charge contribute in equal measure to the emittance growth during decompression. It is shown that a chicane for this purpose must not be as weak and long as affordable to reduce coherent synchrotron radiation, but that an intermediate length is required. Furthermore, the interplay of the individual concepts and components is assessed in a start-to-end simulation, confirming the feasibility of the

  19. Design of single-longitudinal-mode laser oscillator for edge Thomson scattering system in ITER

    International Nuclear Information System (INIS)

    Hatae, Takaki; Kusama, Yoshinori; Kubomura, Hiroyuki; Matsuoka, Shin-ichi

    2006-06-01

    A high output energy (5J) and high repetition rate (100 Hz) laser system is required for the edge Thomson scattering system in ITER. A YAG laser (Nd:YAG laser) is a first candidate for the laser system satisfying the requirements. It is important to develop a high beam quality and single longitudinal mode (SLM) laser oscillator in order to realize this high power laser system. In this design work, following activities relating to the SLM laser oscillator have been carried out: design of the laser head and the resonator, estimation of the output power for the SLM laser oscillator, consideration of the feedback control scheme and consideration of interface for amplification system to achieve required performance (5J, 100 Hz). It is expected that the designed laser diode (LD) pumped SLM laser oscillator realizes: 100 Hz of repetition rate, 10 mJ of output energy, 10 ns of pulse width, single longitudinal mode, TEM 00 of transversal mode, divergence less than 4 times of the diffraction limit, energy stability within 5%. (author)

  20. Data formats design of laser irradiation experiments in view of data analysis

    International Nuclear Information System (INIS)

    Su Chunxiao; Yu Xiaoqi; Yang Cunbang; Guo Su; Chen Hongsu

    2002-01-01

    The designing rules of new data file formats of laser irradiation experiments are introduced. Object-oriented programs are designed in studying experimental data of the laser facilities. The new format data files are combinations of the experiment data and diagnostic configuration data, which are applied in data processing and analysis. The edit of diagnostic configuration data in data acquisition program is also described

  1. The LIFE Laser Design in Context: A Comparison to the State-of-the-Art

    International Nuclear Information System (INIS)

    Deri, R.J.; Bayramian, A.J.; Erlandson, A.C.

    2011-01-01

    The current point design for the LIFE laser leverages decades of solid-state laser development in order to achieve the performance and attributes required for inertial fusion energy. This document provides a brief comparison of the LIFE laser point design to other state-of-the-art solid-state lasers. Table I compares the attributes of the current LIFE laser point design to other systems. the state-of-the-art for single-shot performance at fusion-relevant beamline energies is exemplified by performance observed on the National Ignition Facility. The state-of-the-art for high average power is exemplified by the Northrup Grumman JHPSSL laser. Several items in Table I deal with the laser efficiency; a more detailed discussion of efficiency can be found in reference 5. The electrical-to-optical efficiency of the LIFE design exceeds that of reference 4 due to the availability of higher efficiency laser diode pumps (70% vs. ∼50% used in reference 4). LIFE diode pumps are discussed in greater detail in reference 6. The 'beam steering' state of the art is represented by the deflection device that will be used in the LIFE laser, not a laser system. Inspection of Table I shows that most LIFE laser attributes have already been experimentally demonstrated. The two cases where the LIFE design is somewhat better than prior experimental work do not involve the development of new concepts: beamline power is increased simply by increasing aperture (as demonstrated by the power/aperture comparison in Table I), and efficiency increases are achieved by employing state-of-the-art diode pumps. In conclusion, the attributes anticipated for the LIFE laser are consistent with the demonstrated performance of existing solid-state lasers.

  2. Compact, passively Q-switched Nd:YAG laser for the MESSENGER mission to Mercury.

    Science.gov (United States)

    Krebs, Danny J; Novo-Gradac, Anne-Marie; Li, Steven X; Lindauer, Steven J; Afzal, Robert S; Yu, Anthony W

    2005-03-20

    A compact, passively Q-switched Nd:YAG laser has been developed for the Mercury Laser Altimeter, an instrument on the Mercury Surface, Space Environment, Geochemistry, and Ranging mission to the planet Mercury. The laser achieves 5.4% efficiency with a near-diffraction-limited beam. It passed all space-flight environmental tests at subsystem, instrument, and satellite integration testing and successfully completes a postlaunch aliveness check en route to Mercury. The laser design draws on a heritage of previous laser altimetry missions, specifically the Ice Cloud and Elevation Satellite and the Mars Global Surveyor, but incorporates thermal management features unique to the requirements of an orbit of the planet Mercury.

  3. Design and development of equipment for laser wire stripping

    Science.gov (United States)

    Iceland, W. F.

    1977-01-01

    Three laser wire strippers have been built for the stripping of Kapton-insulated wire, the baseline wire of the space shuttle orbiter. The strippers are: (1) a bench-model stripper powered with a cw CO2 10.6-micron laser, (2) a hand-held stripper powered with a cw 1.06-micron Nd-YAG laser with an output of 5-7 watts, and (3) a hand-held stripper with a five-inch-long CO2 laser inside the stripping head.

  4. Space electric power design study. [laser energy conversion

    Science.gov (United States)

    Martini, W. R.

    1976-01-01

    The conversion of laser energy to electrical energy is discussed. Heat engines in which the laser heats the gas inside the engine through a window as well as heat engines in which the gas is heated by a thermal energy storage reservoir which has been heated by laser radiation are both evaluated, as well as the necessary energy storage, transmission and conversion components needed for a full system. Preliminary system concepts are presented and a recommended development program is outlined. It appears possible that a free displacer Stirling engine operating directly a linear electric generator can convert 65% of the incident laser energy into electricity.

  5. Novel design of low-jitter 10 GHz all-active monolithic mode-locked lasers

    DEFF Research Database (Denmark)

    Larsson, David; Yvind, Kresten; Christiansen, Lotte Jin

    2004-01-01

    Using a novel design, we have fabricated 10 GHz all-active monolithic mode-locked semiconductor lasers that generate 1.4 ps pulses with record-low timing jitter. The dynamical properties of lasers with 1 and 2 QWs are compared.......Using a novel design, we have fabricated 10 GHz all-active monolithic mode-locked semiconductor lasers that generate 1.4 ps pulses with record-low timing jitter. The dynamical properties of lasers with 1 and 2 QWs are compared....

  6. National Ignition Facility, subsystem design requirements beam control and laser diagnostics SSDR 1.7

    International Nuclear Information System (INIS)

    Bliss, E.

    1996-01-01

    This Subsystem Design Requirement document is a development specification that establishes the performance, design, development, and test requirements for the Alignment subsystem (WBS 1.7.1), Beam Diagnostics (WBS 1.7.2), and the Wavefront Control subsystem (WBS 1.7. 3) of the NIF Laser System (WBS 1.3). These three subsystems are collectively referred to as the Beam Control ampersand Laser Diagnostics Subsystem. The NIF is a multi-pass, 192-beam, high-power, neodymium-glass laser that meets requirements set forth in the NIF SDR 002 (Laser System). 3 figs., 3 tabs

  7. Radiological safety design considerations for a laser-fusion facility

    International Nuclear Information System (INIS)

    Singh, M.S.

    1977-01-01

    Detailed neutronics and photonics calculations have been performed for analyzing prompt and residual radiations and required shielding associated with the design of a laser-fusion facility with a nominal yield of 10 19 neutrons per D--T burn pulse. The standard Livermore Monte Carlo codes and nuclear data cross section libraries were used in calculations. The Bateman equation was used to calculate the accumulation and decay of radionuclide chain products. A number of activation sensitivity experiments were conducted and the results were found to be in very good agreement within 10 percent of those calculated. It has been found that neutron yields of 2 x 10 19 per day can be conducted continuously if the reactor chamber is Kevlar-epoxy or silica, the primary shield is 0.60-m of water immediately on the chamber, and the building concrete is 1.80 m thick. These precautions result in dose equivalents below the primary protection limits inside the target room after a few hours of cool-down per each 10 19 pulse, 10 percent of the primary protection limits immediately outside the target room, and 1 percent of the natural background level at the nearest site boundary

  8. A new design of pulsed laser diode driver system for multistate quantum key distribution

    Science.gov (United States)

    Abdullah, M. S.; Jamaludin, M. Z.; Witjaksono, G.; Mokhtar, M. H. H.

    2011-07-01

    In this paper, we describe a new design of laser diode driver system based on MOSFET current mirror and digital signal controller (DSC). The system is designed to emit stream pairs of photons from three semiconductor laser diodes. The DSC is able to switch between the three laser diodes at constant rate. The duty cycle is maintained at 1% in order to reduce its thermal effect and thus prolong the laser diodes' life cycles. The MOSFET current mirror circuits are capable of delivering constant modulation current with peak current up to 58 mA to each laser diode. This laser driver system will allow the generating biphotons automatically with qubit rate around 8-13% for μ less than or equal to 1, thus making it practical for six-states quantum key distribution implementation.

  9. Resonator design and performance estimation for a space-based laser transmitter

    Science.gov (United States)

    Agrawal, Lalita; Bhardwaj, Atul; Pal, Suranjan; Kamalakar, J. A.

    2006-12-01

    Development of a laser transmitter for space applications is a highly challenging task. The laser must be rugged, reliable, lightweight, compact and energy efficient. Most of these features are inherently achieved by diode pumping of solid state lasers. Overall system reliability can further be improved by appropriate optical design of the laser resonator besides selection of suitable electro-optical and opto-mechanical components. This paper presents the design details and the theoretically estimated performance of a crossed-porro prism based, folded Z-shaped laser resonator. A symmetrically pumped Nd: YAG laser rod of 3 mm diameter and 60 mm length is placed in the gain arm with total input peak power of 1800 W from laser diode arrays. Electro-optical Q-switching is achieved through a combination of a polarizer, a fractional waveplate and LiNbO 3 Q-switch crystal (9 x 9 x 25 mm) placed in the feedback arm. Polarization coupled output is obtained by optimizing azimuth angle of quarter wave plate placed in the gain arm. Theoretical estimation of laser output energy and pulse width has been carried out by varying input power levels and resonator length to analyse the performance tolerances. The designed system is capable of meeting the objective of generating laser pulses of 10 ns duration and 30 mJ energy @ 10 Hz.

  10. A Stochastic Approach to Noise Modeling for Barometric Altimeters

    Directory of Open Access Journals (Sweden)

    Angelo Maria Sabatini

    2013-11-01

    Full Text Available The question whether barometric altimeters can be applied to accurately track human motions is still debated, since their measurement performance are rather poor due to either coarse resolution or drifting behavior problems. As a step toward accurate short-time tracking of changes in height (up to few minutes, we develop a stochastic model that attempts to capture some statistical properties of the barometric altimeter noise. The barometric altimeter noise is decomposed in three components with different physical origin and properties: a deterministic time-varying mean, mainly correlated with global environment changes, and a first-order Gauss-Markov (GM random process, mainly accounting for short-term, local environment changes, the effects of which are prominent, respectively, for long-time and short-time motion tracking; an uncorrelated random process, mainly due to wideband electronic noise, including quantization noise. Autoregressive-moving average (ARMA system identification techniques are used to capture the correlation structure of the piecewise stationary GM component, and to estimate its standard deviation, together with the standard deviation of the uncorrelated component. M-point moving average filters used alone or in combination with whitening filters learnt from ARMA model parameters are further tested in few dynamic motion experiments and discussed for their capability of short-time tracking small-amplitude, low-frequency motions.

  11. Design and performance of a sealed CO2 laser for industrial applications

    International Nuclear Information System (INIS)

    Botero, G; Gomez, D; Nisperuza, D; Bastidas, A

    2011-01-01

    A large amount of materials processing is done using an industrial CO 2 laser operating in the mid-infrared (IR) spectrum. Their high efficiency and tremendous power output have made them one of the most commonly known transition wavelength at 10,6 microns facilitates laser cutting, drilling and marking of a wide variety of materials in the electronics and medical industries. Because lasers are feedback systems, many of their design parameters strongly interact with one another, and arriving at an optimum design requires a really thorough understanding of just how they interact. We report the construction of a sealed CO2 gas discharge laser with a glass laser tube design as well as clear acrylic housing makes this an excellent demonstrational tool. Sealed operation was characterized in mode, power, warm-up and stability over a long time. The results indicate a good operation, optimum wavelength, powers and beam quality will remove material more efficiently in effective industrial applications.

  12. Opto-mechanical design of vacuum laser resonator for the OSQAR experiment

    Science.gov (United States)

    Hošek, Jan; Macúchová, Karolina; Nemcová, Šárka; Kunc, Štěpán.; Šulc, Miroslav

    2015-01-01

    This paper gives short overview of laser-based experiment OSQAR at CERN which is focused on search of axions and axion-like particles. The OSQAR experiment uses two experimental methods for axion search - measurement of the ultra-fine vacuum magnetic birefringence and a method based on the "Light shining through the wall" experiment. Because both experimental methods have reached its attainable limits of sensitivity we have focused on designing a vacuum laser resonator. The resonator will increase the number of convertible photons and their endurance time within the magnetic field. This paper presents an opto-mechanical design of a two component transportable vacuum laser resonator. Developed optical resonator mechanical design allows to be used as a 0.8 meter long prototype laser resonator for laboratory testing and after transportation and replacement of the mirrors it can be mounted on the LHC magnet in CERN to form a 20 meter long vacuum laser resonator.

  13. Multi-megajoule Nd: glass fusion laser design

    International Nuclear Information System (INIS)

    Manes, K.R.

    1986-01-01

    New technologies make multi-megajoule glass lasers economically feasible. Laser architectures using harmonic switchout, target plane holographic injection, phase conjugation, continuous apodization and higher amplifier efficiencies have been devised. A plan for a multi-megajoule laser which can be built for an acceptable cost relies on manufacturing economies of scale and the demonstration of the new technologies presented here. These include continuous pour glass production, rapid harmonic crystal growth, switching of large blocks of power using larger capcaitors packed more economically and by using large identical parts counts

  14. Design and construction of single path Raman laser

    International Nuclear Information System (INIS)

    Mavaddat, M.; Soltanolkotabi, M.

    2007-01-01

    In this paper the stimulated Raman effect has been reported.The pumping laser in this setup is He-Ne with wavelength of 632.8 nm. The first order Stokes line has been observed, to be at 776 nm. The pressure of methane gas in this setup has been increased to 20 bar. The diagram of the effect of the intensity of first order Stokes line as a function of pressure has been plotted. Also, two different pumping laser powers have been used in these investigations. Intensity of first order Stokes line has been increased with increasing gas pressure or laser power.

  15. Design and fabrication of multi-dielectric thin film laser filters and mirrors

    International Nuclear Information System (INIS)

    Alsous, M. B.

    2005-01-01

    Multi-dielectric-film optical filters have designed as mirrors for frequency-doubled-Nd-YAG pumped Raman lasers at different wavelengths (435, 369.9, 319.8, 953.6, 683 nm), and for use in CVL pumped dye lasers: as beam-splitters, antireflection filters, and narrow-band filters. In this work, a theoretical design of these mirrors and filters is given. The treatment and optimization of these designs is detailed in order to overcome the difficulties and reach the final and suitable designs for our needs. In addition, we will describe the evaporation method and the best conditions to do it. These filters should be easy to make and able to resist the laser powers of the pulsed Nd-YAG laser (200mJ/pulse) and the output power of the CVL. Thus, we have adopted designs with the least number of layers and used materials and oxides, which could resist to high laser powers. These filters were tested with laser shots and the convenient designs that were able to support the laser power have been adopted. (Author)

  16. Design of ultrahigh brightness solar-pumped disk laser.

    Science.gov (United States)

    Liang, Dawei; Almeida, Joana

    2012-09-10

    To significantly improve the solar-pumped laser beam brightness, a multi-Fresnel lens scheme is proposed for side-pumping either a single-crystal Nd:YAG or a core-doped ceramic Sm(3+) Nd:YAG disk. Optimum laser system parameters are found through ZEMAX and LASCAD numerical analysis. An ultrahigh laser beam figure of merit B of 53 W is numerically calculated, corresponding to a significant enhancement of more than 180 times over the previous record. 17.7 W/m(2) collection efficiency is also numerically attained. The strong thermal effects that have hampered present-day rod-type solar-pumped lasers can also be largely alleviated.

  17. Conceptual fusion reactor designs based on the laser heat solenoid

    International Nuclear Information System (INIS)

    Steinhauer, L.C.

    1976-01-01

    The feasibility of the laser heated solenoid (LHS) as an approach to fusion and fusion-fission commercial power generation has been examined. The LHS concept is based on magnetic confinement of a long slender plasma column which is partly heated by the axially directed beam from a powerful long wavelength laser. As a pure fusion concept, the LHS configurations studied so far are characterized by fairly difficult engineering constraints, particularly on the magnet, a large laser, and a marginally acceptable system energy balance. As a fusion-fission system, however, the LHS is capable of a very attractive energy balance, has much more relaxed engineering constraints, requires a relatively modest laser, and as such holds great potential as a power generator and fissile fuel breeding scheme

  18. Absolute Sea Level Monitoring and Altimeter Calibration At Gavdos, Crete, Greece

    Science.gov (United States)

    Pavlis, E. C.; Gavdos Team

    We present the mean sea level (MSL) monitoring aspect of the altimeter calibration fa- cility under deployment on western Crete and the isle of Gavdos. The Eastern Mediter- ranean area is one of great interest for its intense tectonic activity as well as for its regional oceanography. Recent observations have convincingly demonstrated the im- portance of that area for the regional meteorological and climatological changes. Tide- gauge monitoring with GPS has gained importance lately since tectonics contaminate the inferred sea level variations, and a global network of tide-gauges with long his- torical records can be used as satellite altimeter calibration sites for current and fu- ture missions (e.g. TOPEX/POSEIDON, GFO, JASON-1, ENVISAT, etc.). This is at present a common IOC-GLOSS-IGS effort, already underway (TIGA). Crete hosts two of the oldest tide-gauges in the regional network and our project will further ex- pand it to the south of the island with a new site on the isle of Gavdos, the southernmost European parcel of land. One component of our "GAVDOS" project is the repeated occupation of two already in existence tide-gauge sites at Souda Bay and Heraklion, and their tie to the new facility. We show here initial results from positioning of these sites and some of the available tidal records. Gavdos is situated under a ground-track crossing point of the present T/P and JASON-1 orbits. It is an ideal calibration site if the tectonic motions are monitored precisely and continuously. Our plans include the deployment of additional instrumentation at this site: GPS and DORIS beacons for positioning, transponders for direct calibration, water vapor radiometers, GPS-loaded buoys, airborne surveys with gravimeters and laser profiling lidars, etc., to ensure the best possible and most reliable results.

  19. Conceptual design of the fast ignition laser fusion power plant (KOYO-Fast). 6. Design of chamber and reactor system

    International Nuclear Information System (INIS)

    Kozaki, Yasuji; Norimatsu, Takayoshi; Furukawa, Hiroyuki; Hayashi, Takumi; Souman, Yoshihito; Nishikawa, Masabumi; Tomabechi, Ken

    2007-01-01

    A conceptual design of the reactor chamber system with LiPb liquid wall based on the fast ignition cone target design and the related reactor systems with exhaust system, laser beam shutter, blanket and cooling system are summarized. The multi overflow fall method was investigated as the structure of chamber and repeating 4 Hz pulse potential. The ablation depth of LiPb liquid wall was estimated and the conditions of repeat of operation were evaluated. The basic design of chamber, selection and conditions of liquid wall chamber, recycle type multi overflow fall (MOF) wall, LiPb two layers blanket structure, basic specification of reactor system, laser beam line shutter, design of chamber exhaust system, cooling system, tritium recovery system, power plant total design and arrangement of chamber and laser beam, and issues are stated. (S.Y.)

  20. Laser penetration spike welding: a welding tool enabling novel process and design opportunities

    Science.gov (United States)

    Dijken, Durandus K.; Hoving, Willem; De Hosson, J. Th. M.

    2002-06-01

    A novel method for laser welding for sheet metal. is presented. This laser spike welding method is capable of bridging large gaps between sheet metal plates. Novel constructions can be designed and manufactured. Examples are light weight metal epoxy multi-layers and constructions having additional strength with respect to rigidity and impact resistance. Its capability to bridge large gaps allows higher dimensional tolerances in production. The required laser systems are commercially available and are easily implemented in existing production lines. The lasers are highly reliable, the resulting spike welds are quickly realized and the cost price per weld is very low.

  1. Advanced design and modeling concepts for recombination x-ray lasers

    International Nuclear Information System (INIS)

    Eder, D.C.; Rosen, M.D.; Shephard, R.; Staffin, R.; Nash, J.K.; Keane, C.J.

    1990-01-01

    Geometric, kinetic, and trapping issues, in short and ultrashort recombination x-ray lasers, are discussed. The design of a composite target consisting of a lasant strip on a plastic backing is described. Examples of modeling showing the effect of photon trapping and uncertainties in other physical processes on calculated gain coefficients are given. A simple and accurate expression for photon trapping in cylindrical geometry is presented. Recombination lasers that have the ground state as the lower laser state are shown to have small I sat 's and corresponding low efficiencies. Scaling laws for femtosecond laser-plasma interactions are presented. 19 refs

  2. Optical design and development of a fiber coupled high-power diode laser system for laser transmission welding of plastics

    Science.gov (United States)

    Rodríguez-Vidal, Eva; Quintana, Iban; Etxarri, Jon; Azkorbebeitia, Urko; Otaduy, Deitze; González, Francisco; Moreno, Fernando

    2012-12-01

    Laser transmission welding (LTW) of thermoplastics is a direct bonding technique already used in different industrial applications sectors such as automobiles, microfluidics, electronics, and biomedicine. LTW evolves localized heating at the interface of two pieces of plastic to be joined. One of the plastic pieces needs to be optically transparent to the laser radiation whereas the other part has to be absorbent, being that the radiation produced by high power diode lasers is a good alternative for this process. As consequence, a tailored laser system has been designed and developed to obtain high quality weld seams with weld widths between 0.7 and 1.4 mm. The developed laser system consists of two diode laser bars (50 W per bar) coupled into an optical fiber using a nonimaging solution: equalization of the beam parameter product (BPP) in the slow and fast axes by a pair of step-mirrors. The power scaling was carried out by means of a multiplexing polarization technique. The analysis of energy balance and beam quality was performed considering ray tracing simulation (ZEMAX) and experimental validation. The welding experiments were conducted on acrylonitrile/butadiene/styrene (ABS), a thermoplastic frequently used in automotive, electronics and aircraft applications, doped with two different concentrations of carbon nanotubes (0.01% and 0.05% CNTs). Quality of the weld seams on ABS was analyzed in terms of the process parameters (welding speed, laser power and clamping pressure) by visual and optical microscope inspections. Mechanical properties of weld seams were analyzed by mechanical shear tests. High quality weld seams were produced in ABS, revealing the potential of the laser developed in this work for a wide range of plastic welding applications.

  3. The science, technology and mission design for the Laser Astrometric test of relativity

    Science.gov (United States)

    Turyshev, Slava G.

    2006-01-01

    The Laser Astrometric Test of Relativity (LATOR) is a Michelson-Morley-type experiment designed to test the Einstein's general theory of relativity in the most intense gravitational environment available in the solar system - the close proximity to the Sun.

  4. Third order mode laser diode: design of a twin photon source

    International Nuclear Information System (INIS)

    Ducci, S.; Berger, V.; Rossi, A. de; Ortiz, V.; Calligaro, M.; Vinter, B.; Nagle, J.; Berger, V.

    2004-01-01

    We demonstrate the lasing action on a third order waveguide mode in a laser diode. The AlGaAs heterostructure has been designed to achieve a parametric emission of photons pairs through modal phase matching. This device is very compact and does not generate coupling loss between the laser source and the non-linear waveguide. It is the first step on the way to design a twin photon micro-source. (A.C.)

  5. Design and evaluation of a laser fusion energy station for industrial applications

    International Nuclear Information System (INIS)

    Kok, K.D.; Bates, F.J.; Denning, R.S.; Triplett, M.B.; Waddell, J.D.

    1978-01-01

    The identification and development of long-term energy options is important in the continued growth of industry in the United States. Fusion and particularly laser fusion is one of the possible options. This paper applies the criteria used by industry in the selection of an energy source to the first of a series of conceptual designs for a laser fusion energy station. Several conclusions are presented including the constraints placed on the design by the criteria

  6. Innovative opto-mechanical design of a laser head for compact thin-disk

    Science.gov (United States)

    Macúchová, Karolina; Smrž, Martin; Řeháková, Martina; Mocek, Tomáš

    2016-11-01

    We present recent progress in design of innovative versatile laser head for lasers based on thin-disk architecture which are being constructed at the HiLASE centre of the IOP in the Czech Republic. Concept of thin-disk laser technology allows construction of lasers providing excellent beam quality with high average output power and optical efficiency. Our newly designed thin-disk carrier and pump module comes from optical scheme consisting of a parabolic mirror and roof mirrors proposed in 90's. However, mechanical parts and a cooling system were in-house simplified and tailor-made to medium power lasers since no suitable setup was commercially available. Proposed opto-mechanical design is based on stable yet easily adjustable mechanics. The only water nozzle-cooled component is a room-temperature-operated thindisk mounted on a special cooling finger. Cooling of pump optics was replaced by heat conductive transfer from mirrors made of special Al alloy to a massive brass baseplate. Such mirrors are easy to manufacture and very cheap. Presented laser head was manufactured and tested in construction of Er and Yb doped disk lasers. Details of the latest design will be presented.

  7. Novel target design for enhanced laser driven proton acceleration

    Directory of Open Access Journals (Sweden)

    Malay Dalui

    2017-09-01

    Full Text Available We demonstrate a simple method of preparing structured target for enhanced laser-driven proton acceleration under target-normal-sheath-acceleration scheme. A few layers of genetically modified, clinically grown micron sized E. Coli bacteria cell coated on a thin metal foil has resulted in an increase in the maximum proton energy by about 1.5 times and the total proton yield is enhanced by approximately 25 times compared to an unstructured reference foil at a laser intensity of 1019 W/cm2. Particle-in-cell simulations on the system shows that the structures on the target-foil facilitates anharmonic resonance, contributing to enhanced hot electron production which leads to stronger accelerating field. The effect is observed to grow as the number of structures is increased in the focal area of the laser pulse.

  8. Design, fabrication, and optimization of quantum cascade laser cavities and spectroscopy of the intersubband gain

    Science.gov (United States)

    Dirisu, Afusat Olayinka

    Quantum Cascade (QC) lasers are intersubband light sources operating in the wavelength range of ˜ 3 to 300 mum and are used in applications such as sensing (environmental, biological, and hazardous chemical), infrared countermeasures, and free-space infrared communications. The mid-infrared range (i.e. lambda ˜ 3-30 mum) is of particular importance in sensing because of the strong interaction of laser radiation with various chemical species, while in free space communications the atmospheric windows of 3-5 mum and 8-12 mum are highly desirable for low loss transmission. Some of the requirements of these applications include, (1) high output power for improved sensitivity; (2) high operating temperatures for compact and cost-effective systems; (3) wide tunability; (4) single mode operation for high selectivity. In the past, available mid-infrared sources, such as the lead-salt and solid-state lasers, were bulky, expensive, or emit low output power. In recent years, QC lasers have been explored as cost-effective and compact sources because of their potential to satisfy and exceed all the above requirements. Also, the ultrafast carrier lifetimes of intersubband transitions in QC lasers are promising for high bandwidth free-space infrared communication. This thesis was focused on the improvement of QC lasers through the design and optimization of the laser cavity and characterization of the laser gain medium. The optimization of the laser cavity included, (1) the design and fabrication of high reflection Bragg gratings and subwavelength antireflection gratings, by focused ion beam milling, to achieve tunable, single mode and high power QC lasers, and (2) modeling of slab-coupled optical waveguide QC lasers for high brightness output beams. The characterization of the QC laser gain medium was carried out using the single-pass transmission experiment, a sensitive measurement technique, for probing the intersubband transitions and the electron distribution of QC lasers

  9. Application of pulsed laser for evaluation and optimization of SEU-Hard Designs

    International Nuclear Information System (INIS)

    McMorrow, D.; Melinger, J.S.; Buchner, St.; Scott, T.; Brown, R.D.

    1999-01-01

    Pulsed laser SEU tests are used to pinpoint and characterize sensitive nodes of CMOS circuits and to provide feedback relevant to the development and optimization of radiation-hard designs. The present study reveals several examples of the quantitative utility of the laser system. The most direct approach to obtaining quantitative thresholds from laser SEU tests involved a calibration of the measured laser upset thresholds against heavy ion results. This procedure requires only a correlation between the laser and heavy ion measurements. This study shows that this correlation exists and is particularly strong and that the calibration factor is identical to that determined in previous studies. The laser SEU threshold energy corresponds to the most sensitive node located with the laser probe. The ion-equivalent laser LET is calculated using the calibration factor noted above. The measured heavy ion threshold is given as a range since heavy-ion upset measurements are discrete: the upper value gives the lowest LET ion to induce an upset; the lower value gives the next lower LET investigated. Laser SEU measurements often can be used directly for hardness assurance or diagnosis studies. (A.C.)

  10. Design and reliability analysis of a novel laser acupuncture device

    Science.gov (United States)

    Pan, Boan; Zhong, Fulin; Zhao, Ke; Li, Ting

    2018-02-01

    Acupuncture has a long history of more than 2000 years in China. However, traditional acupuncture adopts metallic needles which may bring discomfort and pricking to patients. Laser acupuncture (LA) is a non-invasive and painless way to achieve some therapeutic effects. And compared to traditional acupuncture, LA is free from infection. Taking these advantages of LA into consideration, we innovatively developed a portable laser acupuncture device with therapy part and detection part together. Therapy part sends out laser at the wavelength of 650 nm onto special acupoints of patients. And detection part includes integrated light-emitting diode (LED, 735/805/850 nm) and photodiode (OPT101). The detection part is used for the data collection for calculation of hemodynamic parameters based on near-infrared spectroscopy (NIRS). In this work, we carried out current-power test for sensitivity of therapy part. And we also conducted liquid-model optical experiment and arm blocking test for the sensitivity and effectiveness of detection part. The final results demonstrated great potential and reliability of the novel laser acupuncture device. In the future, we will apply this device in clinical applications to verify the effectiveness of the device and improve the reliability for more treatment of diseases.

  11. Optomechatronics Design and Control for Confocal Laser Scanning Microscopy

    NARCIS (Netherlands)

    Yoo, H.W.

    2015-01-01

    Confocal laser scanning microscopy (CLSM) is considered as one of the major advancements in microscopy in the last century and is widely accepted as a 3D fluorescence imaging tool for biological studies. For the emerging biological questions CLSM requires fast imaging to detect rapid biological

  12. Picosecond laser machined designed patterns with anti-ice effect

    NARCIS (Netherlands)

    Del Cerro, D.A.; Römer, G.R.B.E.; Huis in 't Veld, A.J.

    2010-01-01

    Micromachining using ultra short laser pulses (USLP) has evolved over the past years as a versatile tool for introducing functional features in surfaces at a micrometric and even at a sub wavelength scale. Being able to control the surface topography at this level provides a method to change the

  13. Laser diode stack beam shaping for efficient and compact long-range laser illuminator design

    Science.gov (United States)

    Lutz, Y.; Poyet, J. M.

    2014-04-01

    Laser diode stacks are interesting laser sources for active imaging illuminators. They allow the accumulation of large amounts of energy in multi-pulse mode, which is best suited for long-range image recording. Even when the laser diode stacks are equipped with fast-axis collimation (FAC) and slow-axis collimation (SAC) micro-lenses, their beam parameter products BPP are not compatible with direct use in highly efficient and compact illuminators. This is particularly true when narrow divergences are required such as for long-range applications. A solution to overcome these difficulties is to enhance the poor slow-axis BPP by virtually restacking the laser diode stack. We present a beam shaping and homogenization method that is low-cost and efficient and has low alignment sensitivity. After conducting simulations, we have realized and characterized the illuminator. A compact long-range laser illuminator has been set up with a divergence of 3.5×2.6 mrad and a global efficiency of 81%. Here, a projection lens with a clear aperture of 62 mm and a focal length of 571 mm was used.

  14. Testing in a stratospheric balloon of a semiconductor detector altimeter

    International Nuclear Information System (INIS)

    Gilly, L.; Jourdan, P.

    1968-01-01

    An altimeter containing a semiconductor detector has been operated on flight. We have used a stratospheric balloon launched from AIRE-SUR-ADOUR with the C.N.E.S. collaboration. During this assay two apparatus have been used. The first allowed to follow the balloon during its ascension and descent, the second to follow its evolution at its maximum altitude. Informations transmitted by radio and recorded on Magnetophon, have been studied after the flight. Results are identical with these given by the barometer used by the C.N.E.S. in this essay. (authors) [fr

  15. Preliminary design of experiment high power density laser beam interaction with plasmas and development of a cold cathode electron beam laser amplifier

    International Nuclear Information System (INIS)

    Mosavi, R.K.; Kohanzadeh, Y.; Taherzadeh, M.; Vaziri, A.

    1976-01-01

    This experiment is designed to produce plasma by carbon dioxide pulsed laser, to measure plasma parameters and to study the interaction of the produced plasma with intense laser beams. The objectives of this experiment are the following: 1. To set up a TEA CO 2 laser oscillator and a cold cathode electron beam laser amplifier together as a system, to produce high energy optical pulses of short duration. 2. To achieve laser intensities of 10 11 watt/cm 2 or more at solid targets of polyethylene (C 2 H 4 )n, lithium hydride (LiH), and lithium deuteride in order to produce high temperature plasmas. 3. To design and develop diagnostic methods for studies of laser-induced plasmas. 4. To develop a high power CO 2 laser amplifier for the purpose of upgrading the optical energy delivered to the targets

  16. Measurement of the sea surface wind speed and direction by an airborne microwave radar altimeter

    Energy Technology Data Exchange (ETDEWEB)

    Nekrassov, A. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Hydrophysik

    2001-07-01

    A pilot needs operational information about wind over sea as well as wave height to provide safety of a hydroplane landing on water. Near-surface wind speed and direction can be obtained with an airborne microwave scatterometer, radar designed for measuring the scatter characteristics of a surface. Mostly narrow-beam antennas are applied for such wind measurement. Unfortunately, a microwave narrow-beam antenna has considerable size that hampers its placing on flying apparatus. In this connection, a possibility to apply a conventional airborne radar altimeter as a scatterometer with a nadir-looking wide-beam antenna in conjunction with Doppler filtering for recovering the wind vector over sea is discussed, and measuring algorithms of sea surface wind speed and direction are proposed. The obtained results can be used for creation of an airborne radar system for operational measurement of the sea roughness characteristics and for safe landing of a hydroplane on water. (orig.)

  17. GEOS-C altimeter attitude bias error correction. [gate-tracking radar

    Science.gov (United States)

    Marini, J. W.

    1974-01-01

    A pulse-limited split-gate-tracking radar altimeter was flown on Skylab and will be used aboard GEOS-C. If such an altimeter were to employ a hypothetical isotropic antenna, the altimeter output would be independent of spacecraft orientation. To reduce power requirements the gain of the altimeter antenna proposed is increased to the point where its beamwidth is only a few degrees. The gain of the antenna consequently varies somewhat over the pulse-limited illuminated region of the ocean below the altimeter, and the altimeter output varies with antenna orientation. The error introduced into the altimeter data is modeled empirically, but close agreements with the expected errors was not realized. The attitude error effects expected with the GEOS-C altimeter are modelled using a form suggested by an analytical derivation. The treatment is restricted to the case of a relatively smooth sea, where the height of the ocean waves are small relative to the spatial length (pulse duration times speed of light) of the transmitted pulse.

  18. Design of a high pulse repitition frequency carbon dioxide laser for processing high damage threshold materials

    Science.gov (United States)

    Chatwin, Christopher R.; McDonald, Donald W.; Scott, Brian F.

    1989-07-01

    The absence of an applications led design philosophy has compromised both the development of laser source technology and its effective implementation into manufacturing technology in particular. For example, CO2 lasers are still incapable of processing classes of refractory and non-ferrous metals. Whilst the scope of this paper is restricted to high power CO2 lasers; the design methodology reported herein is applicable to source technology in general, which when exploited, will effect an expansion of applications. The CO2 laser operational envelope should not only be expanded to incorporate high damage threshold materials but also offer a greater degree of controllability. By a combination of modelling and experimentation the requisite beam characteristics, at the workpiece, were determined then utilised to design the Laser Manufacturing System. The design of sub-system elements was achieved by a combination of experimentation and simulation which benefited from a comprehensive set of software tools. By linking these tools the physical processes in the laser - electron processes in the plasma, the history of photons in the resonator, etc. - can be related, in a detailed model, to the heating mechanisms in the workpiece.

  19. Designing Pulse Laser Surface Modification of H13 Steel Using Response Surface Method

    Science.gov (United States)

    Aqida, S. N.; Brabazon, D.; Naher, S.

    2011-01-01

    This paper presents a design of experiment (DOE) for laser surface modification process of AISI H13 tool steel in achieving the maximum hardness and minimum surface roughness at a range of modified layer depth. A Rofin DC-015 diffusion-cooled CO2 slab laser was used to process AISI H13 tool steel samples. Samples of 10 mm diameter were sectioned to 100 mm length in order to process a predefined circumferential area. The parameters selected for examination were laser peak power, overlap percentage and pulse repetition frequency (PRF). The response surface method with Box-Behnken design approach in Design Expert 7 software was used to design the H13 laser surface modification process. Metallographic study and image analysis were done to measure the modified layer depth. The modified surface roughness was measured using two-dimensional surface profilometer. The correlation of the three laser processing parameters and the modified surface properties was specified by plotting three-dimensional graph. The hardness properties were tested at 981 mN force. From metallographic study, the laser modified surface depth was between 37 μm and 150 μm. The average surface roughness recorded from the 2D profilometry was at a minimum value of 1.8 μm. The maximum hardness achieved was between 728 and 905 HV0.1. These findings are significant to modern development of hard coatings for wear resistant applications.

  20. Design and development of laser eye protection filter

    International Nuclear Information System (INIS)

    Ahmed, K; Khan, A N; Rauf, A; Gul, A; Aslam, M

    2013-01-01

    Laser based devices, have been operational for measurement of distances horizontally and vertically in avionics and surveillance industries. These equipments are functional on pulsed Nd:YAG laser at 1064nm, this wavelength elevate the risk of eye exposure to personnel at unexpected levels. In this paper the eye protection filters, for the wavelength 1064nm were developed with soft (ZnS) and hard (TiO 2 ) coating materials by using thin film vacuum coating technique. The damage threshold of the filter is 0.2 J/cm 2 . Transmission characteristics are measured and discussed. Optical damage threshold (for eye 5 × 10 −6 J/cm2) at various distances is also simulated.

  1. Design and Analysis of Megawatt Class Free Electron Laser Weapons

    Science.gov (United States)

    2015-12-01

    amplifier, FEL modeling, atmospheric propagation modeling 15. NUMBER OF PAGES 93 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18...METRICS We define the target of interest as a sea skimming anti-ship missile. To achieve a hard-kill, we assume that the laser needs to melt a hole... skimming anti-ship missiles where achieving a hard kill in a matter of a couple of seconds is critical. However, for softer and slower moving targets

  2. Inference of Altimeter Accuracy on Along-track Gravity Anomaly Recovery

    Directory of Open Access Journals (Sweden)

    LI Yang

    2015-04-01

    Full Text Available A correlation model between along-track gravity anomaly accuracy, spatial resolution and altimeter accuracy is proposed. This new model is based on along-track gravity anomaly recovery and resolution estimation. Firstly, an error propagation formula of along-track gravity anomaly is derived from the principle of satellite altimetry. Then the mathematics between the SNR (signal to noise ratio and cross spectral coherence is deduced. The analytical correlation between altimeter accuracy and spatial resolution is finally obtained from the results above. Numerical simulation results show that along-track gravity anomaly accuracy is proportional to altimeter accuracy, while spatial resolution has a power relation with altimeter accuracy. e.g., with altimeter accuracy improving m times, gravity anomaly accuracy improves m times while spatial resolution improves m0.4644 times. This model is verified by real-world data.

  3. Investigation on gas medium parameters for an ArF excimer laser through orthogonal experimental design

    Science.gov (United States)

    Song, Xingliang; Sha, Pengfei; Fan, Yuanyuan; Jiang, R.; Zhao, Jiangshan; Zhou, Yi; Yang, Junhong; Xiong, Guangliang; Wang, Yu

    2018-02-01

    Due to complex kinetics of formation and loss mechanisms, such as ion-ion recombination reaction, neutral species harpoon reaction, excited state quenching and photon absorption, as well as their interactions, the performance behavior of different laser gas medium parameters for excimer laser varies greatly. Therefore, the effects of gas composition and total gas pressure on excimer laser performance attract continual research studies. In this work, orthogonal experimental design (OED) is used to investigate quantitative and qualitative correlations between output laser energy characteristics and gas medium parameters for an ArF excimer laser with plano-plano optical resonator operation. Optimized output laser energy with good pulse to pulse stability can be obtained effectively by proper selection of the gas medium parameters, which makes the most of the ArF excimer laser device. Simple and efficient method for gas medium optimization is proposed and demonstrated experimentally, which provides a global and systematic solution. By detailed statistical analysis, the significance sequence of relevant parameter factors and the optimized composition for gas medium parameters are obtained. Compared with conventional route of varying single gas parameter factor sequentially, this paper presents a more comprehensive way of considering multivariables simultaneously, which seems promising in striking an appropriate balance among various complicated parameters for power scaling study of an excimer laser.

  4. Design of a Novel Servo-motorized Laser Device for Visual Pathways Diseases Therapy

    Directory of Open Access Journals (Sweden)

    Carlos Ignacio Sarmiento

    2015-12-01

    Full Text Available We discuss a novel servo-motorized laser device and a research protocol for visual pathways diseases therapies. The proposed servo-mechanized laser device can be used for potential rehabilitation of patients with hemianopia, quadrantanopia, scotoma, and some types of cortical damages. The device uses a semi spherical structure where the visual stimulus will be shown inside, according to a previous stimuli therapy designed by an ophthalmologist or neurologist. The device uses a pair of servomotors (with torque=1.5kg, which controls the laser stimuli position for the internal therapy and another pair for external therapy. Using electronic tools such as microcontrollers along with miscellaneous electronic materials, combined with LabVIEW based interface, a control mechanism is developed for the new device. The proposed device is well suited to run various visual stimuli therapies. We outline the major design principles including the physical dimensions, laser device’s kinematical analysis and the corresponding software development.

  5. Conceptual design of a hybrid KrF laser system for ICF commercial applications

    International Nuclear Information System (INIS)

    Harris, D.B.; Lowenthal, D.D.

    1986-01-01

    KrF lasers appear to be the most efficient lasers operating near the optimal wavelength for laser fusion. Most high-efficiency, low-cost KrF laser designs use large electron-beam-driven amplifiers and use pure angular multiplexing for the required pulse compression. A recent study carried out by Los Alamos National Lab. and Spectra Technology has defied a high-efficiency hybrid KrF laser system architecture that uses both angular multiplexing and Raman beam combination. The high overall system efficiency of this hybrid design, ∼ 12%, is achieved primarily through the use of electron-beam sustained discharge lasers (EBSDL), and by using the efficient forward rotational Raman process in hydrogen. The new system appears attractive as a commercial-applications driver because the calculated efficiency is higher than the usual large electron-beam-pumped (EBP) KrF laser/pure angular multiplexing approach. In this paper, the hybrid system architecture will be described, and the trade-offs with respect to the large EBP amplifier/angular multiplexed system will be discussed

  6. Conceptual design of a hybrid KrF laser system for ICF commercial applications

    International Nuclear Information System (INIS)

    Harris, D.B.; Lowenthal, D.D.

    1986-01-01

    KrF lasers appear to be the most efficient lasers operating near the optimal wavelength for laser fusion. Most high-efficiency, low-cost KrF laser designs use large electron-beam driven amplifiers and use pure angular multiplexing for the required pulse compression. A recent study carried out by Los Alamos and Spectra Technology has defined a high-efficiency hybrid KrF laser system architecture that uses both angular multiplexing and Raman beam combination. The high overall system efficiency of this hybrid design, approximately 12%, is achieved primarily through the use of e-beam sustained discharge lasers (EBSDL), and by using the efficient forward rotational Raman process in hydrogen. The new system appears attractive as a commercial-applications driver because the calculated efficiency is higher than the usual large e-beam pumped (EBP) KrF laser/pure angular multiplexing approach. In this paper, the hybrid system architecture is described, and the tradeoffs with respect to the large EBP amplifier/angular multiplexed system are discussed

  7. A novel DWDM method to design a 100-kW Laser

    Science.gov (United States)

    Basu, Santanu

    2010-02-01

    In this paper, I will present the design analysis of a novel concept that may be used to generate a diffraction-limited beam from an aperture so that as much as 450 kW of laser power can be efficiently deposited on a diffraction-limited spot at a range. The laser beam will be comprised of many closely spaced wavelength channels as in a DWDM. The technique relies on the ability of an angular dispersion amplifier to multiplex a large number of high power narrow frequency lasers, wavelengths of which may be as close as 0.4 nm.

  8. Design considerations for the use of laser-plasma accelerators for advanced space radiation studies

    Science.gov (United States)

    Königstein, T.; Karger, O.; Pretzler, G.; Rosenzweig, J. B.; Hidding, B.; Hidding

    2012-08-01

    We present design considerations for the use of laser-plasma accelerators for mimicking space radiation and testing space-grade electronics. This novel application takes advantage of the inherent ability of laser-plasma accelerators to produce particle beams with exponential energy distribution, which is a characteristic shared with the hazardous relativistic electron flux present in the radiation belts of planets such as Earth, Saturn and Jupiter. Fundamental issues regarding laser-plasma interaction parameters, beam propagation, flux development, and experimental setup are discussed.

  9. Between-cycle laser system for depressurization and resealing of modified design nuclear fuel assemblies

    International Nuclear Information System (INIS)

    Bradley, J.G.

    1982-01-01

    A laser beam is used to puncture fuel cladding for release of contained pressurized fission gas from plenum sections or irradiated fuel pins. Exhausted fission gases are collected and trapped for safe disposal. The laser beam, adjusted to welding mode, is subsequently used to reseal the puncture holes. The fuel assembly is returned to additional irradiation or, if at end of reactivity lifetime, is routed to reprocess. The fuel assembly design provides graded cladding lengths, by rows or arrays, such that the cladding of each component fuel element of the assembly is accessible to laser beam reception

  10. Design and Performance Analysis of Laser Displacement Sensor Based on Position Sensitive Detector (PSD)

    International Nuclear Information System (INIS)

    Song, H X; Wang, X D; Ma, L Q; Cai, M Z; Cao, T Z

    2006-01-01

    By using PSD as sensitive element, and laser diode as emitting element, laser displacement sensor based on triangulation method has been widely used. From the point of view of design, sensor and its performance were studied. Two different sensor configurations were described. Determination of the dimension, sensing resolution and comparison of the two different configurations were presented. The factors affecting the performance of the laser displacement sensor were discussed and two methods, which can eliminate the affection of dark current and environment light, are proposed

  11. Aurora project: optical design for a kilojoule class KrF laser

    International Nuclear Information System (INIS)

    Hanlon, J.; McLeod, J.; Sollid, J.E.; Horn, W. III; Carmichael, R.; Kortegaard, B.; Woodfin, G.; Rosocha, L.

    1985-01-01

    Aurora is a 248-nm, 10-kilojoule laser system being built at Los Alamos National Laboratory to demonstrate the feasibility of large KrF laser systems for laser fusion. It was designed as a test bed to demonstrate: (1) efficiet energy extraction at 248 nm; (2) an angularly multiplexed optical system that is scaleable to large system designs; (3) the control of parasitics and ASE (amplified spontaneous emission); (4) long path pulse propagation at uv wavelengths; (5) alignment systems for multibeam systems; and (6) new or novel approaches to optical hardware that can lead to cost reduction on large systems. In this paper only issues pertinent to the optical system are addressed. First, a description of the entire system is given. The design constraints on the optical system are explained, concurrent with a discussion of the final design. This is followed by a very brief discussion of coatings; in particular, the use of sol-gels for antireflection coatings is presented

  12. Engineering design of the Nova Laser Facility for inertial-confinement fusion

    International Nuclear Information System (INIS)

    Simmons, W.W.; Godwin, R.O.; Hurley, C.A.

    1982-01-01

    The design of the Nova Laser Facility for inertial confinement fusion experiments at Lawrence Livermore National Laboratory is presented from an engineering perspective. Emphasis is placed upon design-to-performance requirements as they impact the various subsystems that comprise this complex experimental facility

  13. Applying Laser Cutting Techniques through Horology for Teaching Effective STEM in Design and Technology

    Science.gov (United States)

    Jones, Lewis C. R.; Tyrer, John R.; Zanker, Nigel P.

    2013-01-01

    This paper explores the pedagogy underpinning the use of laser manufacturing methods for the teaching of science, technology, engineering and mathematics (STEM) at key stage 3 design and technology. Clock making (horology) has been a popular project in design and technology (D&T) found in many schools, typically it focuses on aesthetical…

  14. A design of energy detector for ArF excimer lasers

    Science.gov (United States)

    Feng, Zebin; Han, Xiaoquan; Zhou, Yi; Bai, Lujun

    2017-08-01

    ArF excimer lasers with short wavelength and high photon energy are widely applied in the field of integrated circuit lithography, material processing, laser medicine, and so on. Excimer laser single pulse energy is a very important parameter in the application. In order to detect the single pulse energy on-line, one energy detector based on photodiode was designed. The signal processing circuit connected to the photodiode was designed so that the signal obtained by the photodiode was amplified and the pulse width was broadened. The amplified signal was acquired by a data acquisition card and stored in the computer for subsequent data processing. The peak of the pulse signal is used to characterize the single pulse energy of ArF excimer laser. In every condition of deferent pulse energy value levels, a series of data about laser pulses energy were acquired synchronously using the Ophir energy meter and the energy detector. A data set about the relationship between laser pulse energy and the peak of the pulse signal was acquired. Then, by using the data acquired, a model characterizing the functional relationship between the energy value and the peak value of the pulse was trained based on an algorithm of machine learning, Support Vector Regression (SVR). By using the model, the energy value can be obtained directly from the energy detector designed in this project. The result shows that the relative error between the energy obtained by the energy detector and by the Ophir energy meter is less than 2%.

  15. Preliminary design and estimate of capital and operating costs for a production scale application of laser decontamination technology

    International Nuclear Information System (INIS)

    Pang, Ho-ming; Edelson, M.C.

    1994-01-01

    The application of laser ablation technology to the decontamination of radioactive metals, particularly the surfaces of equipment, is discussed. Included is information related to the design, capital and operating costs, and effectiveness of laser ablation technology, based on commercial excimer and Nd:YAG lasers, for the decontamination of production scale equipment

  16. Spatial filter lens design for the main laser of the National Ignition Facility

    International Nuclear Information System (INIS)

    Korniski, R.J.

    1998-01-01

    The National Ignition Facility (NIF), being designed and constructed at Lawrence Livermore National Laboratory (LLNL), comprises 192 laser beams The lasing medium is neodymium in phosphate glass with a fundamental frequency (1ω) of 1 053microm Sum frequency generation in a pair of conversion crystals (KDP/KD*P) will produce 1 8 megajoules of the third harmonic light (3ω or λ=351microm) at the target The purpose of this paper is to provide the lens design community with the current lens design details of the large optics in the Main Laser This paper describes the lens design configuration and design considerations of the Main Laser The Main Laser is 123 meters long and includes two spatial filters one 13 5 meters and one 60 meters These spatial filters perform crucial beam filtering and relaying functions We shall describe the significant lens design aspects of these spatial filter lenses which allow them to successfully deliver the appropriate beam characteristic onto the target For an overview of NIF please see ''Optical system design of the National Ignition Facility,'' by R Edward English. et al also found in this volume

  17. Design of an ignition target for the laser megajoule, mitigating parametric instabilities

    International Nuclear Information System (INIS)

    Laffite, S.; Loiseau, P.

    2010-01-01

    Laser plasma interaction (LPI) is a critical issue in ignition target design. Based on both scaling laws and two-dimensional calculations, this article describes how we can constrain a laser megajoule (LMJ) [J. Ebrardt and J. M. Chaput, J. Phys.: Conf. Ser. 112, 032005 (2008)] target design by mitigating LPI. An ignition indirect drive target has been designed for the 2/3 LMJ step. It requires 0.9 MJ and 260 TW of laser energy and power, to achieve a temperature of 300 eV in a rugby-shaped Hohlraum and give a yield of about 20 MJ. The study focuses on the analysis of linear gain for stimulated Raman and Brillouin scatterings. Enlarging the focal spot is an obvious way to reduce linear gains. We show that this reduction is nonlinear with the focal spot size. For relatively small focal spot area, linear gains are significantly reduced by enlarging the focal spot. However, there is no benefit in too large focal spots because of necessary larger laser entrance holes, which require more laser energy. Furthermore, this leads to the existence, for a given design, of a minimum value for linear gains for which we cannot go below.

  18. Design of an ignition target for the laser megajoule, mitigating parametric instabilities

    Science.gov (United States)

    Laffite, S.; Loiseau, P.

    2010-10-01

    Laser plasma interaction (LPI) is a critical issue in ignition target design. Based on both scaling laws and two-dimensional calculations, this article describes how we can constrain a laser megajoule (LMJ) [J. Ebrardt and J. M. Chaput, J. Phys.: Conf. Ser. 112, 032005 (2008)] target design by mitigating LPI. An ignition indirect drive target has been designed for the 2/3 LMJ step. It requires 0.9 MJ and 260 TW of laser energy and power, to achieve a temperature of 300 eV in a rugby-shaped Hohlraum and give a yield of about 20 MJ. The study focuses on the analysis of linear gain for stimulated Raman and Brillouin scatterings. Enlarging the focal spot is an obvious way to reduce linear gains. We show that this reduction is nonlinear with the focal spot size. For relatively small focal spot area, linear gains are significantly reduced by enlarging the focal spot. However, there is no benefit in too large focal spots because of necessary larger laser entrance holes, which require more laser energy. Furthermore, this leads to the existence, for a given design, of a minimum value for linear gains for which we cannot go below.

  19. An experimental study of noise in mid-infrared quantum cascade lasers of different designs

    Science.gov (United States)

    Schilt, Stéphane; Tombez, Lionel; Tardy, Camille; Bismuto, Alfredo; Blaser, Stéphane; Maulini, Richard; Terazzi, Romain; Rochat, Michel; Südmeyer, Thomas

    2015-04-01

    We present an experimental study of noise in mid-infrared quantum cascade lasers (QCLs) of different designs. By quantifying the high degree of correlation occurring between fluctuations of the optical frequency and voltage between the QCL terminals, we show that electrical noise is a powerful and simple mean to study noise in QCLs. Based on this outcome, we investigated the electrical noise in a large set of 22 QCLs emitting in the range of 7.6-8 μm and consisting of both ridge-waveguide and buried-heterostructure (BH) lasers with different geometrical designs and operation parameters. From a statistical data processing based on an analysis of variance, we assessed that ridge-waveguide lasers have a lower noise than BH lasers. Our physical interpretation is that additional current leakages or spare injection channels occur at the interface between the active region and the lateral insulator in the BH geometry, which induces some extra noise. In addition, Schottky-type contacts occurring at the interface between the n-doped regions and the lateral insulator, i.e., iron-doped InP, are also believed to be a potential source of additional noise in some BH lasers, as observed from the slight reduction in the integrated voltage noise observed at the laser threshold in several BH-QCLs.

  20. Optical system design with common aperture for mid-infrared and laser composite guidance

    Science.gov (United States)

    Zhang, Xuanzhi; Yang, Zijian; Sun, Ting; Yang, Huamei; Han, Kunye; Hu, Bo

    2017-02-01

    When the field of operation of precision strike missiles is more and more complicated, autonomous seekers will soon encounter serious difficulties, especially with regard to low signature targets and complex scenarios. So the dual-mode sensors combining an imaging sensor with a semi-active laser seeker are conceived to overcome these specific problems. Here the sensors composed a dual field of view mid-infrared thermal imaging camera and a laser range finder have the common optical aperture which produced the minization of seeker construction. The common aperture optical systems for mid-infrared and laser dual-mode guildance have been developed, which could meet the passive middle infrared high-resolution imaging and the active laser high-precision indication and ranging. The optical system had good image quality, and fulfilled the performance requirement of seeker system. The design and expected performance of such a dual-mode optical system will be discussed.

  1. Conceptual design of a 1.5-MJ, 2-Hz KrF fusion laser system

    International Nuclear Information System (INIS)

    Caird, J.; Allen, W.O.; Hipkin, H.G.

    1980-12-01

    The report consists of two major elements: Section II presents an overview of the design study and discusses the major results and conclusions derived from this study; and Section III provides details of the technical analyses and results and presents technical summaries that discuss e-beam pulsed-power conditioning, optical-system design, mechanical-systems design, facilities, overall laser-system efficiency, and capital costs

  2. Conceptual design considerations and neutronics of lithium fall laser fusion target chambers

    International Nuclear Information System (INIS)

    Meier, W.R.; Thomson, W.B.

    1978-01-01

    Atomics International and Lawrence Livermore Laboratory are involved in the conceptual design of a laser fusion power plant incorporating the lithium fall target chamber. In this paper we discuss some of the more important design considerations for the target chamber and evaluate its nuclear performance. Sizing and configuration of the fall, hydraulic effects, and mechanical design considerations are addressed. The nuclear aspects examined include tritium breeding, energy deposition, and radiation damage

  3. Conceptual design considerations and neutronics of lithium fall laser target chambers

    International Nuclear Information System (INIS)

    Meier, W.R.; Thomson, W.B.

    1978-01-01

    Atomics International and Lawrence Livermore Laboratory are involved in the conceptual design of a laser fusion power plant incorporating the lithium fall target chamber. In this paper we discuss some of the more important design considerations for the target chamber and evaluate its nuclear performance. Sizing and configuration of the fall, hydraulic effects, and mechanical design considerations are addressed. The nuclear aspects examined include tritium breeding, energy deposition, and radiation damage

  4. Design of an Optical System for High Power CO2 Laser Cutting

    DEFF Research Database (Denmark)

    de Lange, D.F.; Meijer, J.; Nielsen, Jakob Skov

    2003-01-01

    The results of a design study for the optical system for cutting with high power CO2 lasers (6 kW and up) will be presented. As transparent materials cannot be used for these power levels, mirrors have been applied. A coaxial cutting gas supply has been designed with a laser beam entrance into th...... independent of the entering beam angle or position. manufacturing tolerances have been compensated in a one time adjustment during the assembly of the optical system. Preliminary cutting results in 13 mm thick steel in a shipyard application show a signinficant improvement in the cutting performance....

  5. Design of an electron injector for multi-stages laser wakefield acceleration

    International Nuclear Information System (INIS)

    Audet, T.

    2016-01-01

    Laser wakefield acceleration (LWFA) is a particle acceleration process relying on the interaction between high intensity laser pulses, of the order of 10 18 W/cm 2 and a plasma. The plasma wave generated in the laser wake sustain high amplitude electric fields (1- 100 GV/m). Those electric fields are 3 orders of magnitude higher than maximum electric fields in radio frequency cavities and represent the main benefit of LWFA, allowing more compact acceleration. However improvements of the LWFA-produced electron bunches properties, stability and repetition rate are mandatory for LWFA to be usable for applications. A scheme to improve electron bunches properties and to potentially increase the repetition rate is multi-stage LWFA. The laser plasma electron source, called the injector, has to produce relatively low energy (50 - 100 MeV), but high charge, small size and low divergence electron bunches. Produced electron bunches then have to be transported and injected into a second stage to increase electron kinetic energy. The subject of this thesis is to study and design a laser wakefield electron injector for multistage LWFA. In the frame of CILEX and the two-stages LWFA program, a prototype of the injector was built : ELISA consisting in a variable length gas cell. The plasma electronic density, which is a critical parameter for the control of the electron bunches properties, was characterized both experimentally and numerically. ELISA was used at 2 different laser facilities and physical mechanisms linked to electron bunches properties were studied in function of experimental parameters. A range of experimental parameters suitable for a laser wakefield injector was determined. A magnetic transport and diagnostic line was also built, implemented and tested at the UHI100 laser facility of the CEA Saclay. It allowed a more precise characterization of electron bunches generated with ELISA as well as an estimation of the quality of transported electron bunches for their

  6. High-intensity fibre laser design for micro-machining applications

    Science.gov (United States)

    Ortiz-Neria, D. I.; Martinez-Piñón, F.; Hernandez-Escamilla, H.; Alvarez-Chavez, J. A.

    2010-11-01

    This work is focused on the design of a 250W high-intensity continuous-wave fibre optic laser with a 15μm spot size beam and a beam parameter product (BPP) of 1.8 for its use on Laser-assisted Cold Spray process (LCS) in the micro-machining areas. The metal-powder deposition process LCS, is a novel method based on Cold Spray technique (CS) assisted by laser technology. The LCS accelerates metal powders by the use of a high-pressure gas in order to achieve flash welding of particles over substrate. In LCS, the critical velocity of impact is lower with respect with CS while the powder particle is heated before the deposition by a laser beam. Furthermore, LCS does not heat the powder to achieve high temperatures as it happens in plasma processes. This property puts aside cooling problems which normally happen in sintered processes with high oxygen/nitrogen concentration levels. LCS will be used not only in deposition of thin layers. After careful design, proof of concept, experimental data, and prototype development, it should be feasible to perform micro-machining precise work with the use of the highintensity fibre laser presented in this work, and selective deposition of particles, in a similar way to the well-known Direct Metal Laser Sintering process (DMLS). The fibre laser consists on a large-mode area, Yb3+-doped, semi-diffraction limited, 25-m fibre laser cavity, operating in continuous wave regime. The fibre shows an arguably high slope-efficiency with no signs of roll-over. The measured M2 value is 1.8 and doping concentration of 15000ppm. It was made with a slight modification of the traditional MCVD technique. A full optical characterization will be presented.

  7. Investigation of single lateral mode for 852nm diode lasers with ridge waveguide design

    Science.gov (United States)

    Liu, Chu; Guan, Baolu; Mi, Guoxin; Liao, Yiru; Liu, Zhenyang; Li, Jianjun; Xu, Chen

    2016-11-01

    852nm Narrow linewidth lasers can be widely used in the field of ultra-fine spectrum measurement, Cs atomic clock control, satellite and optical fiber communication and so on. Furthermore, the stability of the single lateral mode is a very important condition to guarantee the narrow linewidth lasers. Here we investigate experimentally the influence of the narrow ridge structure and asymmetrical waveguide design on the stability single lateral mode of an 852nm diode laser. According to the waveguide theoretical analysis, ridge mesa etch depth (Δη , related to the refractive index difference of parallel to the junction) and ridge mesa width (the narrower the more control force to low order mode) are the main elements for lateral modes. In this paper, we designed different structures to investigate and verify major factors for lateral mode by experiment, and to confirm our thought. Finally, the 5μm mesa ridge laser, 800nm etch depth, with groove structure obtains excellent steady single lateral mode output by 150mA operating current and 30°C temperature. The optical spectrum FWHM is 0.5nm and side mode suppression ratio is 27dBm with uncoated. The laser with 1mm cavity length showed the threshold current of 50mA, a lasing wavelength of λ = 852.6nm, slope efficiency of above 0.7mW/mA. We accomplished single lateral mode of ridge waveguide edge-emitting lasers which can also be used as a laser source in the ultra-narrow linewidth external cavity laser system.

  8. Ranging error analysis of single photon satellite laser altimetry under different terrain conditions

    Science.gov (United States)

    Huang, Jiapeng; Li, Guoyuan; Gao, Xiaoming; Wang, Jianmin; Fan, Wenfeng; Zhou, Shihong

    2018-02-01

    Single photon satellite laser altimeter is based on Geiger model, which has the characteristics of small spot, high repetition rate etc. In this paper, for the slope terrain, the distance of error's formula and numerical calculation are carried out. Monte Carlo method is used to simulate the experiment of different terrain measurements. The experimental results show that ranging accuracy is not affected by the spot size under the condition of the flat terrain, But the inclined terrain can influence the ranging error dramatically, when the satellite pointing angle is 0.001° and the terrain slope is about 12°, the ranging error can reach to 0.5m. While the accuracy can't meet the requirement when the slope is more than 70°. Monte Carlo simulation results show that single photon laser altimeter satellite with high repetition rate can improve the ranging accuracy under the condition of complex terrain. In order to ensure repeated observation of the same point for 25 times, according to the parameters of ICESat-2, we deduce the quantitative relation between the footprint size, footprint, and the frequency repetition. The related conclusions can provide reference for the design and demonstration of the domestic single photon laser altimetry satellite.

  9. Reconfigurable Computing As an Enabling Technology for Single-Photon-Counting Laser Altimetry

    Science.gov (United States)

    Powell, Wesley; Hicks, Edward; Pinchinat, Maxime; Dabney, Philip; McGarry, Jan; Murray, Paul

    2003-01-01

    Single-photon-counting laser altimetry is a new measurement technique offering significant advantages in vertical resolution, reducing instrument size, mass, and power, and reducing laser complexity as compared to analog or threshold detection laser altimetry techniques. However, these improvements come at the cost of a dramatically increased requirement for onboard real-time data processing. Reconfigurable computing has been shown to offer considerable performance advantages in performing this processing. These advantages have been demonstrated on the Multi-KiloHertz Micro-Laser Altimeter (MMLA), an aircraft based single-photon-counting laser altimeter developed by NASA Goddard Space Flight Center with several potential spaceflight applications. This paper describes how reconfigurable computing technology was employed to perform MMLA data processing in real-time under realistic operating constraints, along with the results observed. This paper also expands on these prior results to identify concepts for using reconfigurable computing to enable spaceflight single-photon-counting laser altimeter instruments.

  10. Genetic algorithm for the design of high frequency diffraction gratings for high power laser applications

    Science.gov (United States)

    Thomson, Martin J.; Waddie, Andrew J.; Taghizadeh, Mohammad R.

    2006-04-01

    We present a genetic algorithm with small population sizes for the design of diffraction gratings in the rigorous domain. A general crossover and mutation scheme is defined, forming fifteen offspring from 3 parents, which enables the algorithm to be used for designing gratings with diverse optical properties by careful definition of the merit function. The initial parents are randomly selected and the parents of the subsequent generations are selected by survival of the fittest. The performance of the algorithm is demonstrated by designing diffraction gratings with specific application to high power laser beam lines. Gratings are designed that act as beam deflectors, polarisers, polarising beam splitters, harmonic separation gratings and pulse compression gratings. By imposing fabrication constraints within the design process, we determine which of these elements have true potential for application within high power laser beam lines.

  11. Basic design considerations for free-electron lasers driven by electron beams from RF accelerators

    Science.gov (United States)

    Gover, A.; Freund, H.; Granatstein, V. L.; McAdoo, J. H.; Tang, C.-M.

    A design procedure and design criteria are derived for free-electron lasers driven by electron beams from RF accelerators. The procedure and criteria permit an estimate of the oscillation-buildup time and the laser output power of various FEL schemes: with waveguide resonator or open resonator, with initial seed-radiation injection or with spontaneous-emission radiation source, with a linear wiggler or with a helical wiggler. Expressions are derived for computing the various FEL parameters, allowing for the design and optimization of the FEL operational characteristics under ideal conditions or with nonideal design parameters that may be limited by technological or practical constraints. The design procedure enables one to derive engineering curves and scaling laws for the FEL operating parameters. This can be done most conveniently with a computer program based on flowcharts given in the appendices.

  12. Application of Factorial Design for Gas Parameter Optimization in CO2 Laser Welding

    DEFF Research Database (Denmark)

    Gong, Hui; Dragsted, Birgitte; Olsen, Flemming Ove

    1997-01-01

    The effect of different gas process parameters involved in CO2 laser welding has been studied by applying two-set of three-level complete factorial designs. In this work 5 gas parameters, gas type, gas flow rate, gas blowing angle, gas nozzle diameter, gas blowing point-offset, are optimized...... to be a very useful tool for parameter optimi-zation in laser welding process. Keywords: CO2 laser welding, gas parameters, factorial design, Analysis of Variance........ The bead-on-plate welding specimens are evaluated by a number of quality char-acteristics, such as the penetration depth and the seam width. The significance of the gas pa-rameters and their interactions are based on the data found by the Analysis of Variance-ANOVA. This statistic methodology is proven...

  13. Designing an ultrafast laser virtual laboratory using MATLAB GUIDE

    International Nuclear Information System (INIS)

    Cambronero-López, F; Gómez-Varela, A I; Bao-Varela, C

    2017-01-01

    In this work we present a virtual simulator developed using the MATLAB GUIDE environment based on the numerical resolution of the nonlinear Schrödinger equation (NLS) and using the split step method for the study of the spatial–temporal propagation of nonlinear ultrashort laser pulses. This allows us to study the spatial–temporal propagation of ultrafast pulses as well as the influence of high-order spectral phases such as group delay dispersion and third-order dispersion on pulse compression in time. The NLS can describe several nonlinear effects, in particular in this paper we consider the Kerr effect, cross-polarized wave generation and cubic–quintic propagation in order to highlight the potential of this equation combined with the GUIDE environment. Graphical user interfaces are commonly used in science and engineering teaching due to their educational value, and have proven to be an effective way to engage and motivate students. Specifically, the interactive graphical interfaces presented provide the visualization of some of the most important nonlinear optics phenomena and allows users to vary the values of the main parameters involved. (paper)

  14. Millimeter wave free electron laser amplifiers: Experiments and designs

    International Nuclear Information System (INIS)

    Bidwell, S.W.; Zhang, Z.X.; Antonsen, T.M. Jr.; Bensen, D.M.; Destler, W.W.; Granatstein, V.L.; Lantham, P.E.; Levush, B.; Rodgers, J.

    1991-01-01

    Free electron laser amplifies are investigated as sources of high- average-power (1 MW) millimeter to submillimeter wave radiation (200 GHz - 600 GHz) for application to electron cyclotron resonance heating of magnetically confined fusion plasmas. As a stepping-stone to higher frequencies and cw operation a pulsed amplifier (τ pulse ≅ 80 ns) at 98 GHz is being developed. Status is reported on this experiment which investigates linear gain amplification with use of sheet electron beam (transverse cross section = 0.1 cm x 2.0 cm, V beam = 440 keV, I beam ≅ 10 A) and short-period wiggler (ell w = 0.96 cm) and with expected output of 140 W. Predictions of gain and efficiency from a 1-D universal formulation are presented. Beam propagation results, with wiggler focusing as a means of sheet beam confinement in both transverse dimensions, through the 54 cm (56 period) pulsed electromagnet wiggler are discussed. Peak wiggler fields of 5.1 kG on-axis have been achieved

  15. Designing an ultrafast laser virtual laboratory using MATLAB GUIDE

    Science.gov (United States)

    Cambronero-López, F.; Gómez-Varela, A. I.; Bao-Varela, C.

    2017-05-01

    In this work we present a virtual simulator developed using the MATLAB GUIDE environment based on the numerical resolution of the nonlinear Schrödinger equation (NLS) and using the split step method for the study of the spatial-temporal propagation of nonlinear ultrashort laser pulses. This allows us to study the spatial-temporal propagation of ultrafast pulses as well as the influence of high-order spectral phases such as group delay dispersion and third-order dispersion on pulse compression in time. The NLS can describe several nonlinear effects, in particular in this paper we consider the Kerr effect, cross-polarized wave generation and cubic-quintic propagation in order to highlight the potential of this equation combined with the GUIDE environment. Graphical user interfaces are commonly used in science and engineering teaching due to their educational value, and have proven to be an effective way to engage and motivate students. Specifically, the interactive graphical interfaces presented provide the visualization of some of the most important nonlinear optics phenomena and allows users to vary the values of the main parameters involved.

  16. Design and Development of High-Repetition-Rate Satellite Laser Ranging System

    Science.gov (United States)

    Choi, Eun-Jung; Bang, Seong-Cheol; Sung, Ki-Pyoung; Lim, Hyung-Chul; Jung, Chan-Gyu; Kim, In-Yeung; Choi, Jae-Seung

    2015-09-01

    The Accurate Ranging System for Geodetic Observation ? Mobile (ARGO-M) was successfully developed as the first Korean mobile Satellite Laser Ranging (SLR) system in 2012, and has joined in the International Laser Ranging Service (ILRS) tracking network, DAEdeoK (DAEK) station. The DAEK SLR station was approved as a validated station in April 2014, through the ILRS station ¡°data validation¡± process. The ARGO-M system is designed to enable 2 kHz laser ranging with millimeter-level precision for geodetic, remote sensing, navigation, and experimental satellites equipped with Laser Retroreflector Arrays (LRAs). In this paper, we present the design and development of a next generation high-repetition-rate SLR system for ARGO-M. The laser ranging rate up to 10 kHz is becoming an important issue in the SLR community to improve ranging precision. To implement high-repetition-rate SLR system, the High-repetition-rate SLR operation system (HSLR-10) was designed and developed using ARGO-M Range Gate Generator (A-RGG), so as to enable laser ranging from 50 Hz to 10 kHz. HSLR-10 includes both hardware controlling software and data post-processing software. This paper shows the design and development of key technologies of high-repetition-rate SLR system. The developed system was tested successfully at DAEK station and then moved to Sejong station, a new Korean SLR station, on July 1, 2015. HSLR-10 will begin normal operations at Sejong station in the near future.

  17. Design of a Piezoelectric-Driven Tilt Mirror for a Fast Laser Scanner

    Science.gov (United States)

    Park, Jung-Ho; Lee, Hu-Seung; Lee, Jae-Hoon; Yun, So-Nam; Ham, Young-Bog; Yun, Dong-Won

    2012-09-01

    Recently, laser scanners have been used for laser processing such as cutting, welding, and grooving, especially in the automotive industry. The laser scanners need a high-speed driving to minimize cracks caused by thermal shock of brittle materials. Therefore, a novel laser processing system that is composed of a laser source and a piezoelectric-driven tilt mirror to control the reflection angle of the laser beam, and a stage equipped with the tilt mirror has been investigated. In this study, a piezoelectric-driven tilt mirror is designed and analyzed for scanning performance to achieve a beam spot of 30 µm, a pattern width of 1 mm, an overlap ratio of 70% of the circle area, and a scanning speed of 1 m/s. Then, structural analysis of the tilt mirror with three piezoelectric actuators is performed to determine the maximum reflection angle and resonance frequency. Finally, a prototype tilt mirror is fabricated and its basic characteristics are experimentally investigated and discussed.

  18. Design and optimization of a compact laser-driven proton beamline.

    Science.gov (United States)

    Scisciò, M; Migliorati, M; Palumbo, L; Antici, P

    2018-04-19

    Laser-accelerated protons, generated by irradiating a solid target with a short, energetic laser pulse at high intensity (I > 10 18  W·cm -2 ), represent a complementary if not outperforming source compared to conventional accelerators, due  to their intrinsic features, such as high beam charge and short bunch duration. However, the broadband energy spectrum of these proton sources is a bottleneck that precludes their use in applications requiring a more reduced energy spread. Consequently, in recent times strong effort has been put to overcome these limits and to develop laser-driven proton beamlines with low energy spread. In this paper, we report on beam dynamics simulations aiming at optimizing a laser-driven beamline - i.e. a laser-based proton source coupled to conventional magnetic beam manipulation devices - producing protons with a reduced energy spread, usable for applications. The energy range of investigation goes from 2 to 20 MeV, i.e. the typical proton energies that can be routinely obtained using commercial TW-power class laser systems. Our beamline design is capable of reducing the energy spread below 20%, still keeping the overall transmission efficiency around 1% and producing a proton spot-size in the range of 10 mm 2 . We briefly discuss the results in the context of applications in the domain of Cultural Heritage.

  19. A new automatic design method to develop multilayer thin film devices for high power laser applications

    International Nuclear Information System (INIS)

    Sahoo, N.K.; Apparao, K.V.S.R.

    1992-01-01

    Optical thin film devices play a major role in many areas of frontier technology like development of various laser systems to the designing of complex and precision optical systems. Design and development of these devices are really challenging when they are meant for high power laser applications. In these cases besides desired optical characteristics, the devices are expected to satisfy a whole range of different needs like high damage threshold, durability etc. In the present work a novel completely automatic design method based on Modified Complex Method has been developed for designing of high power thin film devices. Unlike most of the other methods it does not need any suitable starting design. A quarterwave design is sufficient to start with. If required, it is capable of generating its own starting design. The computer code of the method is very simple to implement. This report discusses this novel automatic design method and presents various practicable output designs generated by it. The relative efficiency of the method along with other powerful methods has been presented while designing a broadband IR antireflection coating. The method is also incorporated with 2D and 3D electric field analysis programmes to produce high damage threshold designs. Some experimental devices developed using such designs are also presented in the report. (author). 36 refs., 41 figs

  20. Design and application of a new modular adapter for laser diffraction characterization of inhalation aerosols

    NARCIS (Netherlands)

    de Boer, Anne; Gjaltema, D; Hagedoorn, P; Schaller, M; Witt, W; Frijlink, H W

    2002-01-01

    An inhaler adapter has been designed for the characterization of the aerosol clouds from medical aerosol generators such as nebulizers, dry powder inhalers (dpis) and metered dose inhalers (mdis) with laser diffraction technology. The adapter has a pre-separator, for separation of large particles

  1. Design and evaluation of modelocked semiconductor lasers for low noise and high stability

    DEFF Research Database (Denmark)

    Yvind, Kresten; Larsson, David; Christiansen, Lotte Jin

    2005-01-01

    We present work on design of monolithic mode-locked semiconductor lasers with focus on the gain medium. The use of highly inverted quantum wells in a low-loss waveguide enables both low quantum noise, low-chirped pulses and a large stability region. Broadband noise measurements are performed...

  2. Design and component specifications for high average power laser optical systems

    Energy Technology Data Exchange (ETDEWEB)

    O' Neil, R.W.; Sawicki, R.H.; Johnson, S.A.; Sweatt, W.C.

    1987-01-01

    Laser imaging and transport systems are considered in the regime where laser-induced damage and/or thermal distortion have significant design implications. System design and component specifications are discussed and quantified in terms of the net system transport efficiency and phase budget. Optical substrate materials, figure, surface roughness, coatings, and sizing are considered in the context of visible and near-ir optical systems that have been developed at Lawrence Livermore National Laboratory for laser isotope separation applications. In specific examples of general applicability, details of the bulk and/or surface absorption, peak and/or average power damage threshold, coating characteristics and function, substrate properties, or environmental factors will be shown to drive the component size, placement, and shape in high-power systems. To avoid overstressing commercial fabrication capabilities or component design specifications, procedures will be discussed for compensating for aberration buildup, using a few carefully placed adjustable mirrors. By coupling an aggressive measurements program on substrates and coatings to the design effort, an effective technique has been established to project high-power system performance realistically and, in the process, drive technology developments to improve performance or lower cost in large-scale laser optical systems. 13 refs.

  3. Design and component specifications for high average power laser optical systems

    International Nuclear Information System (INIS)

    O'Neil, R.W.; Sawicki, R.H.; Johnson, S.A.; Sweatt, W.C.

    1987-01-01

    Laser imaging and transport systems are considered in the regime where laser-induced damage and/or thermal distortion have significant design implications. System design and component specifications are discussed and quantified in terms of the net system transport efficiency and phase budget. Optical substrate materials, figure, surface roughness, coatings, and sizing are considered in the context of visible and near-ir optical systems that have been developed at Lawrence Livermore National Laboratory for laser isotope separation applications. In specific examples of general applicability, details of the bulk and/or surface absorption, peak and/or average power damage threshold, coating characteristics and function, substrate properties, or environmental factors will be shown to drive the component size, placement, and shape in high-power systems. To avoid overstressing commercial fabrication capabilities or component design specifications, procedures will be discussed for compensating for aberration buildup, using a few carefully placed adjustable mirrors. By coupling an aggressive measurements program on substrates and coatings to the design effort, an effective technique has been established to project high-power system performance realistically and, in the process, drive technology developments to improve performance or lower cost in large-scale laser optical systems. 13 refs

  4. Trabeculoperforation? Trabeculoretraction? Trabeculoplasty? Review of the various designations used for laser treatment in primary open-angle glaucoma.

    Science.gov (United States)

    Moulin, F; Haut, J; Abboud, E

    1985-01-01

    A historical recall and an attempt to simplify the numerous terms used to designate laser treatments for primary open-angle glaucoma (POAG) are presented. There are two main types of laser treatment for POAG involving two entirely different procedures. The first one, contemporary with the beginning of laser photocoagulation, imitates the action of the scalpel, namely goniotomy ab interno or trabeculotomy ab externo. The goal of this early procedure was to produce a through and through trabecular hole but instead of the cutting edge of the knife, it uses the explosive effect of the laser. This procedure has been given numerous names. Among the most frequent ones, we find: 'laser trabeculopuncture', 'laseropuncture', 'goniopuncture', 'laser trabeculectomy', 'laser trabeculotomy', 'laser trabeculopexy'. We prefer to gather them under an explicit generic term: 'laser trabeculoperforation'. The results of this procedure have been very disappointing until now, particularly with conventional lasers, e.g. continuous-wave argon laser, owing to the predominance of their thermal effect over their explosive effect and also to the great scarring property of the trabecular meshwork. In the second type of glaucoma laser treatment, instead of trying to make a patent hole in the trabecular meshwork, the surgeon seeks to reshape the inner trabecular surface by means of argon laser microscars in order to produce a reversal of the trabecular collapse, which is now considered to be one of the major etiologies of POAG.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Lasers

    CERN Document Server

    Milonni, Peter W

    1988-01-01

    A comprehensive introduction to the operating principles and applications of lasers. Explains basic principles, including the necessary elements of classical and quantum physics. Provides concise discussions of various laser types including gas, solid state, semiconductor, and free electron lasers, as well as of laser resonators, diffraction, optical coherence, and many applications including holography, phase conjugation, wave mixing, and nonlinear optics. Incorporates many intuitive explanations and practical examples. Discussions are self-contained in a consistent notation and in a style that should appeal to physicists, chemists, optical scientists and engineers.

  6. Data Quality Assessment of In Situ and Altimeter Observations Through Two-Way Intercomparison Methods

    Science.gov (United States)

    Guinehut, Stephanie; Valladeau, Guillaume; Legeais, Jean-Francois; Rio, Marie-Helene; Ablain, Michael; Larnicol, Gilles

    2013-09-01

    This proceeding presents an overview of the two-way inter-comparison activities performed at CLS for both space and in situ observation agencies and why this activity is a required step to obtain accurate and homogenous data sets that can then be used together for climate studies or in assimilation/validation tools. We first describe the work performed in the frame of the SALP program to assess the stability of altimeter missions through SSH comparisons with tide gauges (GLOSS/CLIVAR network). Then, we show how the SSH comparison between the Argo array and altimeter time series allows the detection of drifts or jumps in altimeter (SALP program) but also for some Argo floats (Ifremer/Coriolis center). Lastly, we describe how the combine use of altimeter and wind observations helps the detection of drogue loss of surface drifting buoys (GDP network) and allow the computation of a correction term for wind slippage.

  7. Research on sensor design for internet of things and laser manufacturing

    Science.gov (United States)

    Wang, Tao; Yao, Jianquan; Guo, Ling; Zhang, Yanchun

    2010-12-01

    In this paper, we will introduce the research on sensor design for IOT (Internet of Things) and laser manufacturing, and supporting the establishment of local area IOT. The main contents include studying on the structure designing of silicon micro tilt sensor, data acquisition and processing, addressing implanted and building Local Area IOT with wireless sensor network technology. At last, it is discussed the status and trends of the Internet of Things from the promoters, watchers, pessimists and doers.

  8. The comparison of laser surface designing and pigment printing methods for the product quality

    Science.gov (United States)

    Ozguney, Arif Taner

    2007-07-01

    Developing new designs by using the computer and transferring the designs that are obtained to textile surfaces will not only increase and facilitate the production in a more practical manner, but also help you create identical designs. This means serial manufacturing of the products at standard quality and increasing their added values. Moreover, creating textile designs using the laser will also contribute to the value of the product as far as the consumer is concerned because it will not cause any wearing off and deformation in the texture of the fabric unlike the other methods. In the system that has been designed, the laser beam at selected wavelength and intensity was directed onto a selected textile surface and a computer-controlled laser beam source was used to change the colour substances on the textile surface. Pigment printing is also used for designing in textile and apparel sector. In this method, designs are transferred to the fabric manually by using dyestuff. In this study, the denim fabric used for the surfacing trial was 100% cotton, with a weft count per centimeter of 20 and a warp count per centimeter of 27, with fabric weight of 458 g/m 2. The first step was to prepare 40 pieces of denim samples, half of which were prepared manually pigment printing and the other half by using the laser beam. After this, some test applications were done. The tensile strength, tensile extension and some fastness values of designed pieces with two methods were compared according to the international standards.

  9. Design, fabricate, and test a 1.06μ repetitively pulsed laser. Final report

    International Nuclear Information System (INIS)

    Eggleston, J.M.; Crawford, E.A.

    1985-01-01

    The results of a program to develop the Thomson scattering diagnostic laser are described. Background material and technical justification for the design approach are given. Principal results of the developmental program were the construction of a rep rated slab glass amplifier, and the accumulation of the design knowledge necessary to build such amplifiers for maximum performance. Significant advances were made in reducing second order optical distortions

  10. Optical design of the adaptive optics laser guide star system

    Energy Technology Data Exchange (ETDEWEB)

    Bissinger, H. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    The design of an adaptive optics package for the 3 meter Lick telescope is presented. This instrument package includes a 69 actuator deformable mirror and a Hartmann type wavefront sensor operating in the visible wavelength; a quadrant detector for the tip-tile sensor and a tip-tilt mirror to stabilize atmospheric first order tip-tile errors. A high speed computer drives the deformable mirror to achieve near diffraction limited imagery. The different optical components and their individual design constraints are described. motorized stages and diagnostics tools are used to operate and maintain alignment throughout observation time from a remote control room. The expected performance are summarized and actual results of astronomical sources are presented.

  11. First wall studies of a laser-fusion hybrid reactor design

    International Nuclear Information System (INIS)

    Hovingh, J.

    1976-09-01

    The design of a first wall for a 20 MW thermonuclear power laser fusion hybrid reactor is presented. The 20 mm thick graphite first wall is located 3.5 m from the DT microexplosion with a thermonuclear yield of 10 MJ. Estimates of the energy deposition, temperature, stresses, and material vaporized from the first wall due to the interaction of the x-rays, charged particle debris, and reflected laser light with the graphite are presented, along with a brief description of the analytical methods used for these estimations. Graphite is a viable first wall material for inertially-confined fusion reactors, with lifetimes of a year possible

  12. Design of titania nanotube structures by focused laser beam direct writing

    International Nuclear Information System (INIS)

    Enachi, Mihai; Stevens-Kalceff, Marion A.; Sarua, Andrei; Ursaki, Veaceslav; Tiginyanu, Ion

    2013-01-01

    In this work, we report on electrochemical fabrication of titania films consisting of nanotubes (NTs) and their treatment by focused laser beam. The results of sample characterization by optical and scanning electron microscopy, cathodoluminescence imaging, and Raman scattering scanning spectroscopy are compared to those inherent to specimens subjected to thermal treatment in a furnace. The obtained data demonstrate possibilities for controlling crystallographic structure of TiO 2 NTs by focused laser beam direct writing. These findings open new prospects for the design and fabrication of spatial architectures based on titania nanotubes

  13. Laser fusion reactor design in a fast ignition with a dry wall chamber

    International Nuclear Information System (INIS)

    Ogawa, Yichi; Goto, Takuya; Ninomiya, Daisuke; Hiwatari, Ryoji; Asaoka, Yoshiyuki; Okano, Kunihiko

    2007-01-01

    One of the critical issues in laser fusion reactor design is high pulse heat load on the first wall by the X-rays and the fast/debris ions from fusion burn. There are mainly two concepts for the first wall of laser fusion reactor, a dry wall and a liquid metal wall. We should notice that the fast ignition method can achieve sufficiently high pellet gain with smaller (about 1/10 of the conventional central ignition method) input energy. To take advantage of this property, the design of a laser fusion reactor with a small size dry wall chamber may become possible. Since a small fusion pulse leads to a small electric power, high repetition of laser irradiation is required to keep sufficient electric power. Then we tried to design a laser fusion reactor with a dry wall chamber and a high repetition laser. This is a new challenging path to realize a laser fusion plant. Based on the point model of the core plasma, we have estimated that fusion energy in one pulse can be reduced to be 40 MJ with a pellet gain around G>100. To evaluate the validity of this simple estimation and to optimize the pellet design and the pulse shaping for the fast ignition scenario, we have introduced 1-D hydrodynamic simulation code ILESTA-1D and carried out implosion simulations. Since the code is one-dimensional, the detailed physics process of fast heating cannot be reproduced. Thus the fast heating is reflected in the code as the additional artificial heating source in the energy equation. It is modeled as a homogeneous heating of electrons in core region at the time just before when the maximum compression is achieved. At present we obtained the pellet gain G∝100 with the same input energy as the above estimation by a simple point model (350kJ for implosion, 50kJ for heating and assuming 20% coupling of heating laser). A dry wall is exposed to several threats due to the cyclic load by the high energy X-ray and charged particles: surface melting, physical and chemical sputtering

  14. Topology optimization and laser additive manufacturing in design process of efficiency lightweight aerospace parts

    Science.gov (United States)

    Fetisov, K. V.; Maksimov, P. V.

    2018-05-01

    The paper presents the application of topology optimization and laser additive manufacturing in the design of lightweight aerospace parts. At the beginning a brief overview of the topology optimization algorithm SIMP is given, one of the most commonly used algorithm in FEA software. After that, methodology of parts design with using topology optimization is discussed as well as issues related to designing for additive manufacturing. In conclusion, the practical application of the proposed methodologies is presented using the example of one complex assembly unit. As a result of the new design approach, the mass of product was reduced five times, and twenty parts were replaced by one.

  15. Circular Microstrip Patch Array Antenna for C-Band Altimeter System

    Directory of Open Access Journals (Sweden)

    Asghar Keshtkar

    2008-01-01

    Full Text Available The purpose of this paper is to discuss the practical and experimental results obtained from the design, construction, and test of an array of circular microstrip elements. The aim of this antenna construction was to obtain a gain of 12 dB, an acceptable pattern, and a reasonable value of SWR for altimeter system application. In this paper, the cavity model was applied to analyze the patch and a proper combination of ordinary formulas; HPHFSS software and Microwave Office software were used. The array includes four circular elements with equal sizes and equal spacing and was planed on a substrate. The method of analysis, design, and development of this antenna array is explained completely here. The antenna is simulated and is completely analyzed by commercial HPHFSS software. Microwave Office 2006 software has been used to initially simulate and find the optimum design and results. Comparison between practical results and the results obtained from the simulation shows that we reached our goals by a great degree of validity.

  16. Application of 3D Laser Scanning Technology in Complex Rock Foundation Design

    Science.gov (United States)

    Junjie, Ma; Dan, Lu; Zhilong, Liu

    2017-12-01

    Taking the complex landform of Tanxi Mountain Landscape Bridge as an example, the application of 3D laser scanning technology in the mapping of complex rock foundations is studied in this paper. A set of 3D laser scanning technologies are formed and several key engineering problems are solved. The first is 3D laser scanning technology of complex landforms. 3D laser scanning technology is used to obtain a complete 3D point cloud data model of the complex landform. The detailed and accurate results of the surveying and mapping decrease the measuring time and supplementary measuring times. The second is 3D collaborative modeling of the complex landform. A 3D model of the complex landform is established based on the 3D point cloud data model. The super-structural foundation model is introduced for 3D collaborative design. The optimal design plan is selected and the construction progress is accelerated. And the last is finite-element analysis technology of the complex landform foundation. A 3D model of the complex landform is introduced into ANSYS for building a finite element model to calculate anti-slide stability of the rock, and provides a basis for the landform foundation design and construction.

  17. Highly modular high-brightness diode laser system design for a wide application range

    Science.gov (United States)

    Fritsche, Haro; Kruschke, Bastian; Koch, Ralf; Ferrario, Fabio; Kern, Holger; Pahl, Ullrich; Ehm, Einar; Pflueger, Silke; Grohe, Andreas; Gries, Wolfgang

    2015-03-01

    For an economic production it is important to serve as many applications as possible while keeping the product variations minimal. We present our modular laser design, which is based on single emitters and various combining technics. In a first step we accept a reduction of the very high brightness of the single emitters by vertical stacking. Those emitters can be wavelength stabilized by an external resonator, providing the very same feedback to each of those laser diodes which leads to an output power of about 100W with BPP of BPP. These "500W building blocks" are consequently designed in a way that without any system change new wavelengths can be implemented by only exchanging parts but without change of the production process. This design principal offers the option to adapt the wavelength of those blocks to any applications, from UV, visible into the far IR. From laser pumping and scientific applications to materials processing such as cutting and welding of copper aluminum or steel and also medical application. Operating at wavelengths between 900 nm and 1100 nm, these systems are mainly used in cutting and welding, but the technology can also be adapted to other wavelength ranges, such as 793 nm and 1530 nm. Around 1.5 μm the diodes are already successfully used for resonant pumping of Erbium lasers.[1] Furthermore, the fully integrated electronic concept allows addressing further applications, as it is capable of very short μs pulses up to cw mode operation by simple software commands.

  18. Design of an Experiment to Observe Laser-Plasma Interactions on NIKE

    Science.gov (United States)

    Phillips, L.; Weaver, J.; Manheimer, W.; Zalesak, S.; Schmitt, A.; Fyfe, D.; Afeyan, B.; Charbonneau-Lefort, M.

    2007-11-01

    Recent proposed designs (Obenschain et al., Phys. Plasmas 13 056320 (2006)) for direct-drive ICF targets for energy applications involve high implosion velocities combined with higher laser irradiances. The use of high irradiances increases the likelihood of deleterious laser plasma instabilities (LPI) that may lead, for example, to the generation of fast electrons. The proposed use of a 248 nm KrF laser to drive these targets is expected to minimize LPI; this is being studied by experiments at NRL's NIKE facility. We used a modification of the FAST code that models laser pulses with arbitrary spatial and temporal profiles to assist in designing these experiments. The goal is to design targets and pulseshapes to create plasma conditions that will produce sufficient growth of LPI to be observable on NIKE. Using, for example, a cryogenic DT target that is heated by a brief pulse and allowed to expand freely before interacting with a second, high-intensity pulse, allows the development of long scalelengths at low electron temperatures and leads to a predicted 20-efold growth in two-plasmon amplitude.

  19. Design of optical axis jitter control system for multi beam lasers based on FPGA

    Science.gov (United States)

    Ou, Long; Li, Guohui; Xie, Chuanlin; Zhou, Zhiqiang

    2018-02-01

    A design of optical axis closed-loop control system for multi beam lasers coherent combining based on FPGA was introduced. The system uses piezoelectric ceramics Fast Steering Mirrors (FSM) as actuator, the Fairfield spot detection of multi beam lasers by the high speed CMOS camera for optical detecting, a control system based on FPGA for real-time optical axis jitter suppression. The algorithm for optical axis centroid detecting and PID of anti-Integral saturation were realized by FPGA. Optimize the structure of logic circuit by reuse resource and pipeline, as a result of reducing logic resource but reduced the delay time, and the closed-loop bandwidth increases to 100Hz. The jitter of laser less than 40Hz was reduced 40dB. The cost of the system is low but it works stably.

  20. Design and Construction of a pulsed Nd:YAG laser for LIBS applications

    Science.gov (United States)

    Garcia-Villarreal, A.; Sobral, H.

    2015-01-01

    A multi-pulse Nd:YAG laser was designed and built, that can be used as an excitation source for Laser Induced Breakdown Spectroscopy (LIBS) experiments. A trigger and a power supply for the flash lamp has been successfully developed. A cooling system that uses a distilled water flow for the active medium was implemented. The laser has an output energy of 306 ± 7 mJ for 1 Hz repetition rate and its temporal profile is multi-pulse with 1 ps of average separation between them. To validate the system, the output was used as an ablation source of an aluminum target and the emission was investigated by spectroscopy analysis.

  1. Pickup design for high bandwidth bunch arrival-time monitors in free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Angelovski, Aleksandar; Penirschke, Andreas; Jakoby, Rolf [TU Darmstadt (Germany). Institut fuer Mikrowellentechnik und Photonik; Kuhl, Alexander; Schnepp, Sascha [TU Darmstadt (Germany). Graduate School of Computational Engineering; Bock, Marie Kristin; Bousonville, Michael; Schlarb, Holger [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Weiland, Thomas [TU Darmstadt (Germany). Institut fuer Theorie Elektromagnetischer Felder

    2012-07-01

    The increased demands for low bunch charge operation mode in the free-electron lasers (FELs) require an upgrade of the existing synchronization equipment. As a part of the laser-based synchronization system, the bunch arrival-time monitors (BAMs) should have a sub-10 femtosecond precision for high and low bunch charge operation. In order to fulfill the resolution demands for both modes of operation, the bandwidth of such a BAM should be increased up to a cutoff frequency of 40 GHz. In this talk, we present the design and the realization of high bandwidth cone-shaped pickup electrodes as a part of the BAM for the FEL in Hamburg (FLASH) and the European X-ray free-electron laser (European XFEL). The proposed pickup was simulated with CST STUDIO SUITE, and a non-hermetic model was built up for radio frequency (rf) measurements.

  2. Integrated Chamber Design for the Laser Inertial Fusion Energy (LIFE) Engine

    Energy Technology Data Exchange (ETDEWEB)

    Latkowski, J F; Kramer, K J; Abbott, R P; Morris, K R; DeMuth, J; Divol, L; El-Dasher, B; Lafuente, A; Loosmore, G; Reyes, S; Moses, G A; Fratoni, M; Flowers, D; Aceves, S; Rhodes, M; Kane, J; Scott, H; Kramer, R; Pantano, C; Scullard, C; Sawicki, R; Wilks, S; Mehl, M

    2010-12-07

    The Laser Inertial Fusion Energy (LIFE) concept is being designed to operate as either a pure fusion or hybrid fusion-fission system. A key component of a LIFE engine is the fusion chamber subsystem. The present work details the chamber design for the pure fusion option. The fusion chamber consists of the first wall and blanket. This integrated system must absorb the fusion energy, produce fusion fuel to replace that burned in previous targets, and enable both target and laser beam transport to the ignition point. The chamber system also must mitigate target emissions, including ions, x-rays and neutrons and reset itself to enable operation at 10-15 Hz. Finally, the chamber must offer a high level of availability, which implies both a reasonable lifetime and the ability to rapidly replace damaged components. An integrated LIFE design that meets all of these requirements is described herein.

  3. Integrated Chamber Design for the Laser Inertial Fusion Energy (LIFE) Engine

    International Nuclear Information System (INIS)

    Latkowski, J.F.; Kramer, K.J.; Abbott, R.P.; Morris, K.R.; DeMuth, J.; Divol, L.; El-Dasher, B.; Lafuente, A.; Loosmore, G.; Reyes, S.; Moses, G.A.; Fratoni, M.; Flowers, D.; Aceves, S.; Rhodes, M.; Kane, J.; Scott, H.; Kramer, R.; Pantano, C.; Scullard, C.; Sawicki, R.; Wilks, S.; Mehl, M.

    2010-01-01

    The Laser Inertial Fusion Energy (LIFE) concept is being designed to operate as either a pure fusion or hybrid fusion-fission system. A key component of a LIFE engine is the fusion chamber subsystem. The present work details the chamber design for the pure fusion option. The fusion chamber consists of the first wall and blanket. This integrated system must absorb the fusion energy, produce fusion fuel to replace that burned in previous targets, and enable both target and laser beam transport to the ignition point. The chamber system also must mitigate target emissions, including ions, x-rays and neutrons and reset itself to enable operation at 10-15 Hz. Finally, the chamber must offer a high level of availability, which implies both a reasonable lifetime and the ability to rapidly replace damaged components. An integrated LIFE design that meets all of these requirements is described herein.

  4. Design challenges of a tunable laser interrogator for geo-stationary communication satellites

    Science.gov (United States)

    Ibrahim, Selwan K.; Honniball, Arthur; McCue, Raymond; Todd, Michael; O'Dowd, John A.; Sheils, David; Voudouris, Liberis; Farnan, Martin; Hurni, Andreas; Putzer, Philipp; Lemke, Norbert; Roner, Markus

    2017-09-01

    Recently optical sensing solutions based on fiber Bragg grating (FBG) technology have been proposed for temperature monitoring in telecommunication satellite platforms with an operational life time beyond 15 years in geo-stationary orbit. Developing radiation hardened optical interrogators designed to be used with FBG sensors inscribed in radiation tolerant fibers offer the capabilities of multiplexing multiple sensors on the same fiber and reducing the overall weight by removing the copper wiring harnesses associated with electrical sensors. Here we propose the use of a tunable laser based optical interrogator that uses a semiconductor MG-Y type laser that has no moving parts and sweeps across the C-band wavelength range providing optical power to FBG sensors and optical wavelength references such as athermal Etalons and Gas Cells to guarantee stable operation of the interrogator over its targeted life time in radiation exposed environments. The MG-Y laser was calibrated so it remains in a stable operation mode which ensures that no mode hops occur due to aging of the laser, and/or thermal or radiation effects. The key optical components including tunable laser, references and FBGs were tested for radiation tolerances by emulating the conditions on a geo-stationary satellite including a Total Ionizing Dose (TID) radiation level of up to 100 krad for interrogator components and 25 Mrad for FBGs. Different tunable laser control, and signal processing algorithms have been designed and developed to fit within specific available radiation hardened FPGAs to guarantee operation of a single interrogator module providing at least 1 sample per second measurement capability across engineering model system developed in the frame of an ESA-ARTES program and is planned to be deployed as a flight demonstrator on-board the German Heinrich Hertz geo-stationary satellite.

  5. The ICESat-2 mission: design, status, applications and pre-launch performance assessments for monitoring cryopsheric changes

    Science.gov (United States)

    Neumann, T.; Markus, T.; Csatho, B. M.; Martino, A. J.

    2013-12-01

    NASA's Ice, Cloud, and land Elevation Satellite-2 (ICESat-2) is the next-generation orbiting laser altimeter, following the ICESat mission, which operated between 2003 and 2009. Its primary aim is to monitor sea-ice thickness and ice sheet elevation change at scales from outlet glaciers to the entire ice sheet, and enable global assessment of vegetation canopy height as established by ICESat. ICESat-2 is now in Phase C (Design and Development). It is scheduled to launch in 2016 on a Delta II rocket from Vandenberg Air Force Base in California. ICESat-2 will carry the Advanced Topographic Laser Altimeter System (ATLAS) and collect data to a latitudinal limit of 88 degrees. In contrast to Geoscience Laser Altimeter System (GLAS) on ICESat, ATLAS employs a 6-beam micro-pulse laser photon-counting approach. It uses a high repetition rate (10 kHz; resulting in 70 cm footprint spacing on the ground along the direction of travel) low-power laser in conjunction with single-photon sensitive detectors to measure ranges using 532 nm (green) laser light. In the polar regions, the 91-day repeat orbit pattern with a roughly monthly sub-cycle is designed to monitor seasonal and interannual variations of Greenland and Antarctic ice sheet elevations and monthly sea ice thickness changes. Dense ground-tracks over the rest of the globe achieved through a systematic sequence of off-nadir pointing (resulting in < 2 km ground-track spacing at the equator after two years) will enable measurements of land topography and vegetation canopy heights, allowing estimates of biomass and carbon in above-ground vegetation. While the ICESat-2 mission was optimized for cryospheric science, elevation measurements will be collected over land and oceans as well as histograms of backscatter from the atmosphere. These observations will provide a wealth of opportunities in addition to the primary science objectives, ranging from the retrieval of cloud properties, to river stages, to snow cover, to land

  6. Transceiver design for MSD indoor free-space laser links

    Science.gov (United States)

    Jivkova, S.; Hristov, Boian A.

    2004-06-01

    In Multi-Spot Diffusing (MSD) configuration, the communication channel can be considered virtually ideal at data rates of hundreds of Mbps. Thus, the main concern is power efficiency. We propose transceiver optical designs that allow for a reconfigurable transmitter output and independent communication channels. Transmitter employs multiple light sources that can be turned on and off independently. This way, optical signal is provided only where it is needed, which optimizes power usage. Receiver utilizes an imaging optical system and segmented photodetector, thus performing direction diversity reception. We show that when maximum ratio combining is employed for the electric signals processing and power efficient modulation schemes like L-PPM are used significant power savings can be obtained.

  7. Design and manufacture of customized dental implants by using reverse engineering and selective laser melting technology.

    Science.gov (United States)

    Chen, Jianyu; Zhang, Zhiguang; Chen, Xianshuai; Zhang, Chunyu; Zhang, Gong; Xu, Zhewu

    2014-11-01

    Recently a new therapeutic concept of patient-specific implant dentistry has been advanced based on computer-aided design/computer-aided manufacturing technology. However, a comprehensive study of the design and 3-dimensional (3D) printing of the customized implants, their mechanical properties, and their biomechanical behavior is lacking. The purpose of this study was to evaluate the mechanical and biomechanical performance of a novel custom-made dental implant fabricated by the selective laser melting technique with simulation and in vitro experimental studies. Two types of customized implants were designed by using reverse engineering: a root-analog implant and a root-analog threaded implant. The titanium implants were printed layer by layer with the selective laser melting technique. The relative density, surface roughness, tensile properties, bend strength, and dimensional accuracy of the specimens were evaluated. Nonlinear and linear finite element analysis and experimental studies were used to investigate the stress distribution, micromotion, and primary stability of the implants. Selective laser melting 3D printing technology was able to reproduce the customized implant designs and produce high density and strength and adequate dimensional accuracy. Better stress distribution and lower maximum micromotions were observed for the root-analog threaded implant model than for the root-analog implant model. In the experimental tests, the implant stability quotient and pull-out strength of the 2 types of implants indicated that better primary stability can be obtained with a root-analog threaded implant design. Selective laser melting proved to be an efficient means of printing fully dense customized implants with high strength and sufficient dimensional accuracy. Adding the threaded characteristic to the customized root-analog threaded implant design maintained the approximate geometry of the natural root and exhibited better stress distribution and

  8. Design of multichannel laser interferometry for W7-X

    International Nuclear Information System (INIS)

    Kornejew, P.; Hirsch, M.; Bindemann, T.; Dinklage, A.; Dreier, H.; Hartfuss, H.-J.

    2006-01-01

    An eight channel interferometer is developed for density feedback control and the continuous measurement of electron density profiles in the stellarator W7-X. An additional sightline is launched in the geometry of the Thomson scattering for cross calibration. Due to the W7-X coil geometry access is strongly restricted. This motivates the optimization of the sightline geometry and design studies for supplementary chords. In-vessel retroreflectors will be used and inserted in the first wall elements. To cope with associated mechanical vibrations and thermal drifts during the discharges with envisaged duration of 30 min either two-color or second harmonic interferometry techniques must be applied. Optimum wavelengths are found to be about 10 and 5 μm. A CO 2 /CO interferometer (10 μm/5 μm) will be tested and compared with an existing CO 2 /HeNe test interferometer. A special difficulty of remotely operated diagnostics is the need of long transmission lines with a path length of about 60 m required from the diagnostics location to the torus hall and back. Different arrangements will be compared

  9. Tracking the attenuation and nonbreaking dissipation of swells using altimeters

    Science.gov (United States)

    Jiang, Haoyu; Stopa, Justin E.; Wang, He; Husson, Romain; Mouche, Alexis; Chapron, Bertrand; Chen, Ge

    2016-02-01

    A method for systematically tracking swells across oceanic basins is developed by taking advantage of high-quality data from space-borne altimeters and wave model output. The evolution of swells is observed over large distances based on 202 swell events with periods ranging from 12 to 18 s. An empirical attenuation rate of swell energy of about 4 × 10-7 m-1 is estimated using these observations, and the nonbreaking energy dissipation rates of swells far away from their generating areas are also estimated using a point source model. The resulting acceptance range of nonbreaking dissipation rates is -2.5 to 5.0 × 10-7 m-1, which corresponds to a dissipation e-folding scales of at least 2000 km for steep swells, to almost infinite for small-amplitude swells. These resulting rates are consistent with previous studies using in-situ and synthetic aperture radar (SAR) observations. The frequency dispersion and angular spreading effects during swell propagation are discussed by comparing the results with other studies, demonstrating that they are the two dominant processes for swell height attenuation, especially in the near field. The resulting dissipation rates from these observations can be used as a reference for ocean engineering and wave modeling, and for related studies such as air-sea and wind-wave-turbulence interactions.

  10. An Evaluation of Recent Gravity Models wrt. Altimeter Satellite Missions

    Science.gov (United States)

    Lemoine, Frank G.; Zelensky, N. P.; Luthcke, S. B.; Beckley, B. D.; Chinn, D. S.; Rowlands, D. D.

    2003-01-01

    With the launch of CHAMP and GRACE, we have entered a new phase in the history of satellite geodesy. For the first time, geopotential models are now available based almost exclusively on satellite-satellite tracking either with GPS in the case of the CHAMP-based geopotential models, or co-orbital intersatellite ultra-precise ranging in the case of GRACE. Different groups have analyzed these data, and produced a series of geopotential models (e.g., EIGENlS, EIGEN2, GGM0lS, GGMOlC) that incorporate the new data. We will compare the performance of these "newer" geopotential models with the standard models now used for computations, (e.g., JGM-3, BGM-96, PGS7727, and GRIMS-C1) for TOPEX, JASON, Geosat-Follow-On (GFO), and Envisat using standard metrics such as SLR RMS of fit, altimeter crossovers, and orbit overlaps. Where covariances are available we can evaluate the predicted geographically correlated orbit error. These predicted results can be compared with the Earth-fixed differences between dynamic and reduced-dynamic orbits to test the predictive accuracy of the covariances, as well as to calibrate the error of the solutions.

  11. Probing Small Lakes on Titan Using the Cassini RADAR Altimeter

    Science.gov (United States)

    Mastrogiuseppe, M.; Poggiali, V.; Hayes, A.; Lunine, J. I.; Seu, R.; Lorenz, R. D.; Mitri, G.; Mitchell, K. L.; Janssen, M. A.; Casarano, D.; Notarnicola, C.; Le Gall, A. A.

    2017-12-01

    The T126 Cassini's final flyby of Titan has offered a unique opportunity to observe an area in the Northern Polar terrain, where several small - medium size (10 - 50 km) hydrocarbon lakes are present and have been previously imaged by Cassini. The successful observation allowed the radar to operate at the closest approach over several small lakes, using its altimetry mode for the investigation of depth and liquid composition. Herein we present the result of a dedicate processing previously applied to altimetric data acquired over Ligeia Mare where the radar revealed the bathymetry and composition of the sea [1,2]. We show that, the optimal geometry condition met during the T126 fly-by allowed the radar to probe Titan's lakes revealing that such small liquid bodies can exceed one-hundred meters of depth. [1] M. Mastrogiuseppe et al. (2014, Mar.). The bathymetry of a Titan Sea. Geophysical Research Letters. [Online]. 41 (5), pp. 1432-1437. Available: http://dx.doi.org/10.1002/2013GL058618 [2] M.Mastrogiuseppe et al. (2016, Oct). Radar Sounding Using the Cassini Altimeter: Waveform Modeling and Monte Carlo Approach for Data Inversion of Observations of Titan's Seas, IEEE Transactions On Geoscience And Remote Sensing, Vol. 54, No. 10, doi: 10.1109/TGRS.2016.2563426.

  12. Improved interpretation of satellite altimeter data using genetic algorithms

    Science.gov (United States)

    Messa, Kenneth; Lybanon, Matthew

    1992-01-01

    Genetic algorithms (GA) are optimization techniques that are based on the mechanics of evolution and natural selection. They take advantage of the power of cumulative selection, in which successive incremental improvements in a solution structure become the basis for continued development. A GA is an iterative procedure that maintains a 'population' of 'organisms' (candidate solutions). Through successive 'generations' (iterations) the population as a whole improves in simulation of Darwin's 'survival of the fittest'. GA's have been shown to be successful where noise significantly reduces the ability of other search techniques to work effectively. Satellite altimetry provides useful information about oceanographic phenomena. It provides rapid global coverage of the oceans and is not as severely hampered by cloud cover as infrared imagery. Despite these and other benefits, several factors lead to significant difficulty in interpretation. The GA approach to the improved interpretation of satellite data involves the representation of the ocean surface model as a string of parameters or coefficients from the model. The GA searches in parallel, a population of such representations (organisms) to obtain the individual that is best suited to 'survive', that is, the fittest as measured with respect to some 'fitness' function. The fittest organism is the one that best represents the ocean surface model with respect to the altimeter data.

  13. Nudging Satellite Altimeter Data Into Quasi-Geostrophic Ocean Models

    Science.gov (United States)

    Verron, Jacques

    1992-05-01

    This paper discusses the efficiency of several variants of the nudging technique (derived from the technique of the same name developed by meteorologists) for assimilating altimeter data into numerical ocean models based on quasi-geostrophic formulation. Assimilation experiments are performed with data simulated in the nominal sampling conditions of the Topex-Poseidon satellite mission. Under experimental conditions it is found that nudging on the altimetric sea level is as efficient as nudging on the vorticity (second derivative in space of the dynamic topography), the technique used thus far in studies of this type. The use of altimetric residuals only, instead of the total altimetric sea level signal, is also explored. The critical importance of having an adequate reference mean sea level is largely confirmed. Finally, the possibility of nudging only the signal of sea level tendency (i.e., the successive time differences of the sea level height) is examined. Apart from the barotropic mode, results are not very successful compared with those obtained by assimilating the residuals.

  14. MABEL Photon-Counting Laser Altimetry Data in Alaska for ICESat-2 Simulations and Development

    Science.gov (United States)

    Brunt, Kelly; Neumann, T. A.; Amundson, M.; Kavanaugh, J. L.; Moussavi, M. S.; Walsh, K. M.; Cook, W. B.; Markus, T.

    2016-01-01

    Multiple Altimeter Beam Experimental Lidar (MABEL) maps Alaskan crevasses in detail, using 50 of the expected along-track Advanced Topographic Laser Altimeter System (ATLAS) signal-photon densities over summer ice sheets. Ice, Cloud, and Land Elevation Satellite 2 (ICESat-2) along-track data density, and spatial data density due to the multiple-beam strategy, will provide a new dataset to mid-latitude alpine glacier researchers.

  15. The Design Concept of the First Mobile Satellite Laser Ranging System (ARGO-M in Korea

    Directory of Open Access Journals (Sweden)

    Jung Hyun Jo

    2011-03-01

    Full Text Available Korea Astronomy and Space Science Institute (KASI launched the development project of two satellite laser ranging (SLR systems in early 2008 after the government fund approval of the SLR systems in 2007. One mobile SLR system and one permanent SLR station will be developed with the completion of the project. The main objectives of these systems will be focused on the Space Geodetic researches. A system requirement review was held in the second half of the same year. Through the following system design review meeting and other design reviews, many unsolved technical and engineering issues would be discussed and resolved. However, the design of the mobile SLR system is a corner stone of whole project. The noticeable characteristics of Korea’s first SLR system are 1 use of light weight main mirror, 2 design of compact optical assembly, 3 use of KHz laser pulse, 4 use of commercial laser generator, 5 remote operation capability, 6 automatic tracking, 7 state of art operation system, etc. In this paper, the major user requirement and pre-defined specification are presented and discussed.

  16. Conceptual design of a fast-ignition laser fusion reactor FALCON-D

    International Nuclear Information System (INIS)

    Goto, T.; Ogawa, Y.; Okano, K.; Hiwatari, R.; Asaoka, Y.; Someya, Y.; Sunahara, A.; Johzaki, T.

    2008-10-01

    A new conceptual design of the laser fusion power plant FALCON-D (Fast ignition Advanced Laser fusion reactor CONcept with a Dry wall chamber) has been proposed. The fast ignition method can achieve the sufficient fusion gain for a commercial operation (∼100) with about 10 times smaller fusion yield than the conventional central ignition method. FALCON-D makes full use of this property and aims at designing with a compact dry wall chamber (5 - 6 m radius). 1-D/2-D hydrodynamic simulations showed the possibility of the sufficient gain achievement with a 40 MJ target yield. The design feasibility of the compact dry wall chamber and solid breeder blanket system was shown through the thermomechanical analysis of the dry wall and neutronics analysis of the blanket system. A moderate electric output (∼400 MWe) can be achieved with a high repetition (30 Hz) laser. This dry wall concept not only reduces some difficulties accompanied with a liquid wall but also enables a simple cask maintenance method for the replacement of the blanket system, which can shorten the maintenance time. The basic idea of the maintenance method for the final optics system has also been proposed. Some critical R and D issues required for this design are also discussed. (author)

  17. Bullet Design and Fabrication of Dual Mode Pyroelectric Sensor: High Sensitive Energymeter for Nd: YAG Laser and Detector for Chopped He-Ne Laser

    Directory of Open Access Journals (Sweden)

    S. SATAPATHY

    2008-05-01

    Full Text Available Pyroelectric sensor using TGS has been designed and fabricated which can be operated in laser energy meter mode as well as pyroelectric detector mode. The amplifying circuit configuration has very good signal to noise ratio, very high input impedance and low drift. The pyroelectric sensor has been tested using Q-switched Nd: YAG laser and chopped He-Ne laser. The sensitivity of pyroelectric sensor in energymeter mode is 421.7V/J and the voltage responsivity of the pyroelectric sensor is 3.27 V/W in detector mode.

  18. Development of a light-weight beryllium Cassegrain telescope: from the optical design to the performance measurement

    Science.gov (United States)

    Viertl, Jacques; Greger, Ralf; Di Domenico, Maurizio; Francou, Laurent; Ellouzi, Marina; Blum, Steffen; Kudielka, Klaus; Weigel, Thomas; Rugi Grond, Elisabetta; Piazza, Daniele

    2012-12-01

    The BepiColombo Laser Altimeter (BELA) is selected to fly on board of the ESA's BepiColombo Mercury Planetary Orbiter (MPO). The instrument will be the first European planetary laser altimeter system. RUAG Space is the industrial prime for the Receiver part of the scientific instrument. The BELA Receiver is a joined effort of Swiss industries under the leading role of RUAG and University of Bern as co-Prime. A core element is the light weighted Receiver Telescope (RTL), to collect the laser pulse reflected from the planet's surface. An innovative design was required to deal with the very challenging Mercury's environmental conditions and with the very stringent instrument's mass budget. The Optothermo- mechanical analyses lead to the design of a 1250mm focal length Cassegrain telescope made of Beryllium. It provides an aperture of 204 mm diameter and a 2 mm thick primary mirror for a total mass of less than 600gr. The manufacturing and the integration needed special developments. This paper presents the design analyses and the major challenges which had to be solved. Discussing some aspects of the telescope integration and test campaign, the finally achieved performances and lessons learnt will be presented.

  19. Design and fabrication of radiation shielded laser ablation ICP-MS system

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Yeong Keong; Han, Sun Ho; Park, Soon Dal; Park, Yang Soon; Jee, Kwang Yong; Kim, Won Ho

    2006-09-15

    In relation to high burn up and extended fuel cycle for the fuel cycle efficiency, we need to take chemical analysis of spent nuclear fuel for the integrity of nuclear fuel at high burn up. to measure the isotopic distribution of fission product in a high burn up nuclear fuel, radiation shielded laser ablation system was designed and fabricated. By probing the sample with a laser beam, micro sampling system for the mass analyzer was successfully developed. This report describes the structural design and the function of developed radiation shielded LA system. This system will be used for the analysis of isotopic distribution from core to rim of a spent nuclear fuel prepared from the hot-cell in PIE facility and/or an irradiated fuel from research reactor.

  20. Design of a chamber for deposit of thin films by laser ablation

    International Nuclear Information System (INIS)

    Chirino O, S.

    2001-01-01

    The present work has as purpose to design a vacuum chamber, to the one that is denominated chamber of ablation, in which were carried out deposits of thin films using the well-known technique as laser ablation. To fulfill the purpose, the work has been distributed in the following way: in the chapter 1 there are discussed the generalities of the technique of ablation laser for the obtaining of materials in form of thin film, in the chapter 2 the basic concepts of the vacuum technology are mentioned that includes among other things, systems to produce vacuum and vacuum gages and in the chapter 3 the design of the chamber is presented with the accessories and specific systems. (Author)

  1. Conceptual design and issues of the laser inertial fusion test (LIFT) reactor—targets and chamber systems

    Science.gov (United States)

    Norimatsu, T.; Kozaki, Y.; Shiraga, H.; Fujita, H.; Okano, K.; Members of LIFT Design Team

    2017-11-01

    We present the conceptual design of an experimental laser fusion plant known as the laser inertial fusion test (LIFT) reactor. The conceptual design aims at technically connecting a single-shot experiment and a commercial power plant. The LIFT reactor is designed on a three-phase scheme, where each phase has specific goals and the dedicated chambers of each phase are driven by the same laser. Technical issues related to the chamber technology including radiation safety to repeat burst mode operation are discussed in this paper.

  2. Circuit Design and Implementation of Micro-Displacement Measurement System of Laser Self-Mixing Interference

    Directory of Open Access Journals (Sweden)

    Guang Ya LIU

    2014-02-01

    Full Text Available In this paper we put forward the basic structure of a micro-displacement measuring system based on the basic theory of laser feedback, and designed a hardware circuit of the system, including the LD driver and modulation circuit, photoelectric signal amplifier and filter circuit, which meet the requirements of the follow-up experimental study by theoretical analysis and Multisim simulation to the circuit.

  3. Computational Design of Short Pulse Laser Driven Iron Opacity Measurements at Stellar-Relevant Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Madison E. [Univ. of Florida, Gainesville, FL (United States)

    2017-05-20

    Opacity is a critical parameter in the simulation of radiation transport in systems such as inertial con nement fusion capsules and stars. The resolution of current disagreements between solar models and helioseismological observations would bene t from experimental validation of theoretical opacity models. Overall, short pulse laser heated iron experiments reaching stellar-relevant conditions have been designed with consideration of minimizing tamper emission and optical depth effects while meeting plasma condition and x-ray emission goals.

  4. Recent advancements in system design for miniaturized MEMS-based laser projectors

    Science.gov (United States)

    Scholles, M.; Frommhagen, K.; Gerwig, Ch.; Knobbe, J.; Lakner, H.; Schlebusch, D.; Schwarzenberg, M.; Vogel, U.

    2008-02-01

    Laser projection systems that use the flying spot principle and which are based on a single MEMS micro scanning mirrors are a very promising way to build ultra-compact projectors that may fit into mobile devices. First demonstrators that show the feasibility of this approach and the applicability of the micro scanning mirror developed by Fraunhofer IPMS for these systems have already been presented. However, a number of items still have to be resolved until miniaturized laser projectors are ready for the market. This contribution describes progress on several different items, each of them of major importance for laser projection systems. First of all, the overall performance of the system has been increased from VGA resolution to SVGA (800×600 pixels) with easy connection to a PC via DVI interface or by using the projector as embedded system with direct camera interface. Secondly, the degree of integration of the electronics has been enhanced by design of an application specific analog front end IC for the micro scanning mirror. It has been fabricated in a special high voltage technology and does not only allow to generate driving signals for the scanning mirror with amplitudes of up to 200V but also integrates position detection of the mirror by several methods. Thirdly, first results concerning Speckle reduction have been achieved, which is necessary for generation of images with high quality. Other aspects include laser modulation and solutions regarding projection on tilted screens which is possible because of the unlimited depth of focus.

  5. Conceptual design of a laser fusion power plant. Part I. An integrated facility

    International Nuclear Information System (INIS)

    1981-07-01

    This study is a new preliminary conceptual design and economic analysis of an inertial confinement fusion (ICF) power plant performed by Bechtel under the direction of Lawrence Livermore National Laboratory (LLNL). The purpose of a new conceptual design is to examine alternatives to the LLNL HYLIFE power plant and to incorporate information from the recent liquid metal cooled power plant conceptual design study (CDS) into the reactor system and balance of plant design. A key issue in the design of a laser fusion power plant is the degree of symmetry in the illumination of the target that will be required for a proper burn. Because this matter is expected to remain unresolved for some time, another purpose of this study is to determine the effect of symmetry requirements on the total plant size, layout, and cost

  6. Advanced chip designs and novel cooling techniques for brightness scaling of industrial, high power diode laser bars

    Science.gov (United States)

    Heinemann, S.; McDougall, S. D.; Ryu, G.; Zhao, L.; Liu, X.; Holy, C.; Jiang, C.-L.; Modak, P.; Xiong, Y.; Vethake, T.; Strohmaier, S. G.; Schmidt, B.; Zimer, H.

    2018-02-01

    The advance of high power semiconductor diode laser technology is driven by the rapidly growing industrial laser market, with such high power solid state laser systems requiring ever more reliable diode sources with higher brightness and efficiency at lower cost. In this paper we report simulation and experimental data demonstrating most recent progress in high brightness semiconductor laser bars for industrial applications. The advancements are in three principle areas: vertical laser chip epitaxy design, lateral laser chip current injection control, and chip cooling technology. With such improvements, we demonstrate disk laser pump laser bars with output power over 250W with 60% efficiency at the operating current. Ion implantation was investigated for improved current confinement. Initial lifetime tests show excellent reliability. For direct diode applications 96% polarization are additional requirements. Double sided cooling deploying hard solder and optimized laser design enable single emitter performance also for high fill factor bars and allow further power scaling to more than 350W with 65% peak efficiency with less than 8 degrees slow axis divergence and high polarization.

  7. Design of a high-power Nd:YAG Q-switched laser cavity

    Science.gov (United States)

    Singh, Ikbal; Kumar, Avinash; Nijhawan, O. P.

    1995-06-01

    An electro-optically Q-switched Nd:YAG laser resonator that uses two end prisms placed orthogonally perpendicular to each other has been designed. This configuration improves the stability of the resonator and does not alter the characteristics of the electro-optical Q switch. The outcoupling ratio of the cavity is optimized by a change in the azimuthal angle of a phase-matched Porro prism placed at one end of the cavity. The prism placed at the other end of the cavity is designed so that it introduces a phase change of Pi , regardless of its orientation and index of refraction, resulting in a more efficient and stable cavity.

  8. New vistas in refractive laser beam shaping with an analytic design approach

    Science.gov (United States)

    Duerr, Fabian; Thienpont, Hugo

    2014-05-01

    Many commercial, medical and scientific applications of the laser have been developed since its invention. Some of these applications require a specific beam irradiance distribution to ensure optimal performance. Often, it is possible to apply geometrical methods to design laser beam shapers. This common design approach is based on the ray mapping between the input plane and the output beam. Geometric ray mapping designs with two plano-aspheric lenses have been thoroughly studied in the past. Even though analytic expressions for various ray mapping functions do exist, the surface profiles of the lenses are still calculated numerically. In this work, we present an alternative novel design approach that allows direct calculation of the rotational symmetric lens profiles described by analytic functions. Starting from the example of a basic beam expander, a set of functional differential equations is derived from Fermat's principle. This formalism allows calculating the exact lens profiles described by Taylor series coefficients up to very high orders. To demonstrate the versatility of this new approach, two further cases are solved: a Gaussian to at-top irradiance beam shaping system, and a beam shaping system that generates a more complex dark-hollow Gaussian (donut-like) irradiance profile with zero intensity in the on-axis region. The presented ray tracing results confirm the high accuracy of all calculated solutions and indicate the potential of this design approach for refractive beam shaping applications.

  9. Optical Performance Measurements of the BELA EQM and FM Transmitter Laser during AIV

    Science.gov (United States)

    Althaus, C.; Michaelis, H.; Lingenauber, K.; Behnke, T.; Togno, S. d.; Kallenbach, R.; Wickhusen, K.; Althaus, C.

    2014-04-01

    The BepiColombo Laser Altimeter (BELA) onboard the Mercury Planetary Orbiter is Europe's first built Laser Altimeter for a planetary mission. Its main objectives are global mapping of Mercury's topography as well as measuring its tidal deformations to learn about the internal structure of this small terrestrial planet [1]. Crucial part of the instrument for this task is the transmitter laser. It must withstand all mission phases till operation in orbit and work within tight parameter margins. To ensure this a dedicated verification program has been performed at DLR Institute for Planetary Research Berlin which is described in the present paper.

  10. Design and Study of a Next-Generation Computer-Assisted System for Transoral Laser Microsurgery

    Directory of Open Access Journals (Sweden)

    Nikhil Deshpande PhD

    2018-05-01

    Full Text Available Objective To present a new computer-assisted system for improved usability, intuitiveness, efficiency, and controllability in transoral laser microsurgery (TLM. Study Design Pilot technology feasibility study. Setting A dedicated room with a simulated TLM surgical setup: surgical microscope, surgical laser system, instruments, ex vivo pig larynxes, and computer-assisted system. Subjects and Methods The computer-assisted laser microsurgery (CALM system consists of a novel motorized laser micromanipulator and a tablet- and stylus-based control interface. The system setup includes the Leica 2 surgical microscope and the DEKA HiScan Surgical laser system. The system was validated through a first-of-its-kind observational study with 57 international surgeons with varied experience in TLM. The subjects performed real surgical tasks on ex vivo pig larynxes in a simulated TLM scenario. The qualitative aspects were established with a newly devised questionnaire assessing the usability, efficiency, and suitability of the system. Results The surgeons evaluated the CALM system with an average score of 6.29 (out of 7 in ease of use and ease of learning, while an average score of 5.96 was assigned for controllability and safety. A score of 1.51 indicated reduced workload for the subjects. Of 57 subjects, 41 stated that the CALM system allows better surgical quality than the existing TLM systems. Conclusions The CALM system augments the usability, controllability, and efficiency in TLM. It enhances the ergonomics and accuracy beyond the current state of the art, potentially improving the surgical safety and quality. The system offers the intraoperative automated scanning of customized long incisions achieving uniform resections at the surgical site.

  11. Design and fabrication of a chamber for the deposit of thin films by laser ablation

    International Nuclear Information System (INIS)

    Chirino O, S.; Escobar A, I.; Camps C, E.; Garcia E, J.I.

    2000-01-01

    The laser ablation technique is an alternative for the obtention of thin films which is less expensive, more reliable, efficient and with some advantages with respect to conventional processes. On of the most important components which forms a laser ablation system is the vacuum chamber, that has as general purposes the following: a) To carry out studies about plasma such as optical emission spectroscopy and measurements by deflectometry. b) To carry out an In situ monitoring about the film growth through the reflectivity measurements of the combination substrate-film. c) To deposit thin films of different materials such as oxides, carbon, metals, etc. In this work it is showed how the vacuum chamber was designed and made to perform the store of thin films by laser ablation and for characterising the formed plasma as a result of the ablation process. The chamber design was enough versatile that will allow to add it more accessory just making it simple modifications. Its cost was very cheap more or less one twentieth of a commercial chamber. (Author)

  12. Optical design of the National Ignition Facility main laser and switchyard/target area beam transport systems

    Science.gov (United States)

    Miller, John L.; English, R. Edward, Jr.; Korniski, Ronald J.; Rodgers, J. Michael

    1999-07-01

    The optical design of the main laser and transport mirror sections of the National Ignition Facility are described. For the main laser the configuration, layout constraints, multiple beam arrangement, pinhole layout and beam paths, clear aperture budget, ray trace models, alignment constraints, lens designs, wavefront performance, and pupil aberrations are discussed. For the transport mirror system the layout, alignment controls and clear aperture budget are described.

  13. Modelling of infrared multiphoton absorption and dissociation for design of reactors for isotope separation by lasers

    International Nuclear Information System (INIS)

    Takeuchi, Kazuo; Nakane, Ryohei; Inoue, Cihiro

    1981-01-01

    A series of experiments were performed on infrared laser beam absorption (multiphoton absorption) and subsequent dissociation (multiphoton dissociation) of CF 3 Cl to propose models for the design of reactors for isotope separation by lasers. A parallel beam geometry was utilized in batch irradiation experiments to make direct compilation of lumped-parameter data possible. Multiphoton absorption is found to be expressed by a power-law extension of the law of Lambert and by an addition of a new term for buffer gas effect to the law of Beer. For reaction analysis, a method to evaluate the effect of incomplete mixing on apparent reaction rates is first presented. Secondly, multiphoton dissociation of Cf 3 Cl is found to occur in pseudo-first order fashion and the specific reaction rates for different beam fluence are shown to be correlated to the absorbed energy. (author)

  14. Initial conceptual design study of self-critical nuclear pumped laser systems

    Science.gov (United States)

    Rodgers, R. J.

    1979-01-01

    An analytical study of self-critical nuclear pumped laser system concepts was performed. Primary emphasis was placed on reactor concepts employing gaseous uranium hexafluoride (UF6) as the fissionable material. Relationships were developed between the key reactor design parameters including reactor power level, critical mass, neutron flux level, reactor size, operating pressure, and UF6 optical properties. The results were used to select a reference conceptual laser system configuration. In the reference configuration, the 3.2 m cubed lasing volume is surrounded by a graphite internal moderator and a region of heavy water. Results of neutronics calculations yield a critical mass of 4.9 U(235) in the form (235)UF6. The configuration appears capable of operating in a continuous steady-state mode. The average gas temperature in the core is 600 K and the UF6 partial pressure within the lasing volume is 0.34 atm.

  15. Design and construction of a DC high-brightness laser driven electron gun

    Science.gov (United States)

    Zhao, K.; Geng, R. L.; Wang, L. F.; Zhang, B. C.; Yu, J.; Wang, T.; Wu, G. F.; Song, J. H.; Chen, J. E.

    1996-02-01

    A DC high-brightness laser driven photoemissive electron gun is being developed at Peking University, in order to produce 50-100 ps electron bunches of high quality. The gun consists of a photocathode preparation chamber and a DC acceleration cavity. Different ways of fabricating photocathodes, such as chemical vapor deposition, ion beam implantation and ion beam enhanced deposition, can be adopted. The acceleration gap is designed with the aid of simulation codes EGUN and POISSON. The laser system is a mode-locked Nd-YAG oscillator proceeded by an amplifier at 10 Hz repetition rate, which can deliver three different wavelengths (1064/532/266 nm). The combination of a superconducting cavity with the photocathode preparation chamber is also discussed in this paper.

  16. Design of 20 W fiber-coupled green laser diode by Zemax

    Science.gov (United States)

    Qi, Yunfei; Zhao, Pengfei; Wu, Yulong; Chen, Yongqi; Zou, Yonggang

    2017-09-01

    We represent a design of a 20 W, fiber-coupled diode laser module based on 26 single emitters at 520 nm. The module can produce more than 20 W output power from a standard fiber with core diameter of 400 μm and numerical aperture (NA) of 0.22. To achieve a 20 W laser beam, the spatial beam combination and polarization beam combination by polarization beam splitter are used to combine output of 26 single emitters into a single beam, and then an aspheric lens is used to couple the combined beam into an optical fiber. The simulation shows that the total coupling efficiency is more than 95%. Project supported by the National Key R& D Program of China (No. 2016YFB0402105), the Key Deployment Program of the Chinese Academy of Sciences (No. KGZD-SW-T01-2), and the National Natural Science Foundation of China (No. 61404135).

  17. Design of voice coil motor dynamic focusing unit for a laser scanner

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Moon G.; Kim, Gaeun; Lee, Chan-Woo; Lee, Soo-Hun; Jeon, Yongho, E-mail: princaps@ajou.ac.kr [Department of Mechanical Engineering, Ajou University, San 5, Woncheon-dong, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-749 (Korea, Republic of)

    2014-04-15

    Laser scanning systems have been used for material processing tasks such as welding, cutting, marking, and drilling. However, applications have been limited by the small range of motion and slow speed of the focusing unit, which carries the focusing optics. To overcome these limitations, a dynamic focusing system with a long travel range and high speed is needed. In this study, a dynamic focusing unit for a laser scanning system with a voice coil motor (VCM) mechanism is proposed to enable fast speed and a wide focusing range. The VCM has finer precision and higher speed than conventional step motors and a longer travel range than earlier lead zirconium titanate actuators. The system has a hollow configuration to provide a laser beam path. This also makes it compact and transmission-free and gives it low inertia. The VCM's magnetics are modeled using a permeance model. Its design parameters are determined by optimization using the Broyden–Fletcher–Goldfarb–Shanno method and a sequential quadratic programming algorithm. After the VCM is designed, the dynamic focusing unit is fabricated and assembled. The permeance model is verified by a magnetic finite element method simulation tool, Maxwell 2D and 3D, and by measurement data from a gauss meter. The performance is verified experimentally. The results show a resolution of 0.2 μm and travel range of 16 mm. These are better than those of conventional focusing systems; therefore, this focusing unit can be applied to laser scanning systems for good machining capability.

  18. Ocean current surface measurement using dynamic elevations obtained by the GEOS-3 radar altimeter

    Science.gov (United States)

    Leitao, C. D.; Huang, N. E.; Parra, C. G.

    1977-01-01

    Remote Sensing of the ocean surface from the GEOS-3 satellite using radar altimeter data has confirmed that the altimeter can detect the dynamic ocean topographic elevations relative to an equipotential surface, thus resulting in a reliable direct measurement of the ocean surface. Maps of the ocean dynamic topography calculated over a one month period and with 20 cm contour interval are prepared for the last half of 1975. The Gulf Stream is observed by the rapid slope change shown by the crowding of contours. Cold eddies associated with the current are seen as roughly circular depressions.

  19. Characterising and improving the performance of the Sentinel-3 SRAL altimeter: A Report from SCOOP, SHAPE & SPICE Projects

    Science.gov (United States)

    Restano, Marco; Ambrózio, Américo; Cotton, David; Scoop Team; Fabry, Pierre; Shape Team; McMillan, Malcolm; Spice Team; Benveniste, Jérôme

    2017-04-01

    Under the ESA Scientific Exploitation of Operational Missions (SEOM) Programme, 3 Projects are currently underway to accurately characterise and improve the performance of the Sentinel-3 SRAL SAR mode altimeter. They are: 1) SCOOP (SAR Altimetry Coastal & Open Ocean Performance Exploitation and Roadmap Study) for Coastal and Open Ocean; 2) SHAPE (Sentinel-3 Hydrologic Altimetry PrototypE) for Inland Water; 3) SPICE (Sentinel-3 Performance improvement for ICE sheets) for Ice Sheets. As projects started before the launch of Sentinel-3 (a full SAR mission), calibrated Cryosat-2 data have been used as input to a processor replicating the Sentinel-3 baseline processing. For the SCOOP project, a first test dataset has been released to end users including data from 10 regions of interest. The successful SAMOSA retracker, adopted in the previous CP4O Project (CryoSat Plus for Oceans), has been readapted to re-track Sentinel-3 waveforms. An improved version of SAMOSA will be released at the end of the project. The SHAPE project is working towards the design and assessment of alternative/innovative techniques not implemented in the Sentinel-3 ground segment (performing no Inland Water dedicated processing). Both rivers and lakes will be studied. Amazon, Brahmaputra and Danube have been selected as rivers, whereas Titicaca and Vanern have been chosen as lakes. The study will include the assimilation of output products into hydrological models for all regions of interest. A final dataset will be provided to end users. The SPICE project is addressing four high level objectives: 1) Assess and improve the Delay-Doppler altimeter processing for ice sheets. 2) Assess and develop SAR waveform retrackers for ice sheets. 3) Evaluate the performance of SAR altimetry relative to conventional pulse limited altimetry. 4) Assess the impact on SAR altimeter measurements of radar wave interaction with the snowpack. Dataset used for validation include ICESat and IceBridge products. Vostok

  20. Design definition of the Laser Atmospheric Wind Sounder (LAWS), phase 2. Volume 1: Executive summary

    Science.gov (United States)

    1992-01-01

    The LAWS phase 1 and phase 2 studies have been completed on schedule and have led to significant advances in CO2 laser development. The Phase 2 Design Definition Study has shown that a large scanning mirror/high pulse energy laser LAWS Instrument is feasible and within the existing technology. The capability to monitor wind velocities with backscatter ratios of 10(exp 11) m(exp -1) SR(exp -1) is feasible. The weight budget allocated for the baseline LAWS is adequate, and sufficient reserves exist with the potential downsized configuration. With the possible decrease in available power from the baseline of 2.2 kW guideline, power and shot management is critical for the baseline configuration (15 to 20 J). This is particularly true during the 100 day occultation period each year. With the downsized configurations (5 to 7 J), power management is still necessary during the occultation but is primarily limited to shot management over the polar regions. The breadboard effort has produced significant laser advances for a tight 18 month schedule and the minimum budgets available from NASA, Lockheed, and TDS. Using the NASA funds and Lockheed and TDS fixed assets budgets, the breadboard was designed, fabricated, and brought on-line with first laser light within 16 months after ATP. First laser beam was obtained on 21 April 1992 at a 5 J power level. Tests since then have been conducted at sustained, repetitive pulse levels of over 7 J and 20 Hz. This is an increase of over two or three times greater than any system previously developed from this type laser. Increased power levels and additional life tests will be accomplished in the next LAWS phase. The Lockheed LAWS design will operate in the gravity gradient mode on-orbit, and all possible instrument vibration and jitter modes have been considered. Adequate pointing stability and control is state-of-the-art technology for the critical time periods, frequency rates, and control responses required by LAWS. Lockheed

  1. Gap Width Study and Fixture Design in Laser Butt-Welding

    DEFF Research Database (Denmark)

    Gong, Hui; Olsen, Flemming Ove

    .5-2.0 m/min, the laser power : 2 and 2.6 kW and the focal point position : 0 and -1.2 mm. Quality of all the butt welds are destructively tested according to ISO 13919-1.Influences of the variable process parameters to the maximum allowable gap width are observed as (1) the maximum gap width is inversely......This paper discusses some practical consideration for design of a mechanical fixture, which enables to accurately measure the width of a gap between two stainless steel workpieces and to steadfastly clamp the workpieces for butt-welding with a high power CO2 laser.With such a fixture, a series...... of butt-welding experiment is successfully carried out in order to find the maximum allowable gap width in laser butt-welding. The gap width study (GWS) is performed on the material of SST of W1.4401 (AISI 316) under various welding conditions, which are the gap width : 0.00-0.50 mm, the welding speed : 0...

  2. Design and spectroscopic reflectometry characterization of pulsed laser deposition combinatorial libraries

    International Nuclear Information System (INIS)

    Schenck, Peter K.; Bassim, Nabil D.; Otani, Makoto; Oguchi, Hiroyuki; Green, Martin L.

    2007-01-01

    The goal of the design of pulsed laser deposition (PLD) combinatorial library films is to optimize the compositional coverage of the films while maintaining a uniform thickness. The deposition pattern of excimer laser PLD films can be modeled with a bimodal cos n distribution. Deposited films were characterized using a spectroscopic reflectometer (250-1000 nm) to map the thickness of both single composition calibration films and combinatorial library films. These distribution functions were used to simulate the composition and thickness of multiple target combinatorial library films. The simulations were correlated with electron-probe microanalysis wavelength-dispersive spectroscopy (EPMA-WDS) composition maps. The composition and thickness of the library films can be fine-tuned by adjusting the laser spot size, fluence, background gas pressure, target geometry and other processing parameters which affect the deposition pattern. Results from compositionally graded combinatorial library films of the ternary system Al 2 O 3 -HfO 2 -Y 2 O 3 are discussed

  3. Enabling lightweight designs by a new laser based approach for joining aluminum to steel

    Science.gov (United States)

    Brockmann, Rüdiger; Kaufmann, Sebastian; Kirchhoff, Marc; Candel-Ruiz, Antonio; Müllerschön, Oliver; Havrilla, David

    2015-03-01

    As sustainability is an essential requirement, lightweight design becomes more and more important, especially for mobility. Reduced weight ensures more efficient vehicles and enables better environmental impact. Besides the design, new materials and material combinations are one major trend to achieve the required weight savings. The use of Carbon Fiber Reinforced Plastics (abbr. CFRP) is widely discussed, but so far high volume applications are rarely to be found. This is mainly due to the fact that parts made of CFRP are much more expensive than conventional parts. Furthermore, the proper technologies for high volume production are not yet ready. Another material with a large potential for lightweight design is aluminum. In comparison to CFRP, aluminum alloys are generally more affordable. As aluminum is a metallic material, production technologies for high volume standard cutting or joining applications are already developed. In addition, bending and deep-drawing can be applied. In automotive engineering, hybrid structures such as combining high-strength steels with lightweight aluminum alloys retain significant weight reduction but also have an advantage over monolithic aluminum - enhanced behavior in case of crash. Therefore, since the use of steel for applications requiring high mechanical properties is unavoidable, methods for joining aluminum with steel parts have to be further developed. Former studies showed that the use of a laser beam can be a possibility to join aluminum to steel parts. In this sense, the laser welding process represents a major challenge, since both materials have different thermal expansion coefficients and properties related to the behavior in corrosive media. Additionally, brittle intermetallic phases are formed during welding. A promising approach to welding aluminum to steel is based on the use of Laser Metal Deposition (abbr. LMD) with deposit materials in the form of powders. Within the present work, the advantages of this

  4. Recirculating accelerator driver for a high-power free-electron laser: A design overview

    International Nuclear Information System (INIS)

    Bohn, C.L.

    1997-01-01

    Jefferson Lab is building a free-electron laser (FEL) to produce continuous-wave (cw), kW-level light at 3-6 μm wavelength. A superconducting linac will drive the laser, generating a 5 mA average current, 42 MeV energy electron beam. A transport lattice will recirculate the beam back to the linac for deceleration and conversion of about 75% of its power into rf power. Bunch charge will range up to 135 pC, and bunch lengths will range down to 1 ps in parts of the transport lattice. Accordingly, space charge in the injector and coherent synchrotron radiation in magnetic bends come into play. The machine will thus enable studying these phenomena as a precursor to designing compact accelerators of high-brightness beams. The FEL is scheduled to be installed in its own facility by 1 October 1997. Given the short schedule, the machine design is conservative, based on modifications of the CEBAF cryomodule and MIT-Bates transport lattice. This paper surveys the machine design

  5. Design of tracking mount and controller for mobile satellite laser ranging system

    Science.gov (United States)

    Park, Cheol Hoon; Son, Young Su; Kim, Byung In; Ham, Sang Young; Lee, Sung Whee; Lim, Hyung Chul

    2012-01-01

    In this study, we have proposed and implemented a design for the tracking mount and controller of the ARGO-M (Accurate Ranging system for Geodetic Observation - Mobile) which is a mobile satellite laser ranging (SLR) system developed by the Korea Astronomy and Space Science Institute (KASI) and Korea Institute of Machinery and Materials (KIMM). The tracking mount comprises a few core components such as bearings, driving motors and encoders. These components were selected as per the technical specifications for the tracking mount of the ARGO-M. A three-dimensional model of the tracking mount was designed. The frequency analysis of the model predicted that the first natural frequency of the designed tracking mount was high enough. The tracking controller is simulated using MATLAB/xPC Target to achieve the required pointing and tracking accuracy. In order to evaluate the system repeatability and tracking accuracy of the tracking mount, a prototype of the ARGO-M was fabricated, and repeatability tests were carried out using a laser interferometer. Tracking tests were conducted using the trajectories of low earth orbit (LEO) and high earth orbit (HEO) satellites. Based on the test results, it was confirmed that the prototype of the tracking mount and controller of the ARGO-M could achieve the required repeatability along with a tracking accuracy of less than 1 arcsec.

  6. Recirculating accelerator driver for a high-power free-electron laser: A design overview

    Energy Technology Data Exchange (ETDEWEB)

    Bohn, C.L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    1997-06-01

    Jefferson Lab is building a free-electron laser (FEL) to produce continuous-wave (cw), kW-level light at 3-6 {mu}m wavelength. A superconducting linac will drive the laser, generating a 5 mA average current, 42 MeV energy electron beam. A transport lattice will recirculate the beam back to the linac for deceleration and conversion of about 75% of its power into rf power. Bunch charge will range up to 135 pC, and bunch lengths will range down to 1 ps in parts of the transport lattice. Accordingly, space charge in the injector and coherent synchrotron radiation in magnetic bends come into play. The machine will thus enable studying these phenomena as a precursor to designing compact accelerators of high-brightness beams. The FEL is scheduled to be installed in its own facility by 1 October 1997. Given the short schedule, the machine design is conservative, based on modifications of the CEBAF cryomodule and MIT-Bates transport lattice. This paper surveys the machine design.

  7. Design and fabrication of foam-insulated cryogenic target for wet-wall laser fusion reactor

    International Nuclear Information System (INIS)

    Norimatsu, T.; Takeda, T.; Nagai, K.; Mima, K.; Yamanaka, T.

    2003-01-01

    A foam insulated cryogenic target was proposed for use in a future laser fusion reactor with a wet wall. This scheme can protect the solid DT layer from melting due to surface heating by adsorption of metal vapor without significant reduction in the target gain. Design spaces for the injection velocity and the acceptable vapor pressure in the reactor are discussed. Basic technology to fabricate such structure was demonstrated by emulsion process. Concept of a cryogenic fast-ignition target with a gold guiding cone was proposed together with direct injection filling of liquid DT. (author)

  8. An experimental study of noise in midinfrared quantum cascade lasers of different designs

    OpenAIRE

    Schilt, Stéphane; Tombez, Lionel; Tardy, Camille; Bismuto, Alfredo; Blaser, Stéphane; Maulini, Richard; Terazzi, Romain; Rochat, Michel; Südmeyer, Thomas

    2015-01-01

    We present an experimental study of noise in mid-infrared quantum cascade lasers (QCLs) of differ-ent designs. By quantifying the high degree of correlation occurring between fluctuations of the optical frequency and voltage between the QCL terminals, we show that electrical noise is a powerful and simple mean to study noise in QCLs. Based on this outcome, we investigated the electrical noise in a large set of 22 QCLs emitting in the range of 7.6–8 μm and consisting of both ridge-waveguide and...

  9. HYDRO-ABRASIVE JET CLEANING TECHNOLOGY OF STEEL SHEETS DESIGNED FOR LASER CUTTING

    Directory of Open Access Journals (Sweden)

    I. V. Kachanov

    2013-01-01

    Full Text Available Investigations executed by the BNTU “Shipbuilding and hydraulics” department have shown that rather efficient implementation of the requirements to the metal sheet surface designed for laser cutting can be achieved by using hydro-abrasive jet cleaning while applying water pump equipment with the range of pressure – 20–40 MPa. Type of working fluid plays a significant role for obtaining surface of the required quality. The conducted experiments have demonstrated that the efficient solution of the assigned problems can be ensured by using a working fluid containing bentonite clay, surface-active agent polyacrylamide, soda ash and the rest water.

  10. Optimization of the design and mode of operation of a QD laser for reducing the heat-to-bitrate ratio

    Energy Technology Data Exchange (ETDEWEB)

    Zhukov, A. E., E-mail: zhukale@gmail.com; Savelyev, A. V. [Russian Academy of Sciences, St. Petersburg Academic University-Nanotechnology Research and Education Center (Russian Federation); Maximov, M. V. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Kryzhanovskaya, N. V. [Russian Academy of Sciences, St. Petersburg Academic University-Nanotechnology Research and Education Center (Russian Federation); Gordeev, N. Yu.; Shernyakov, Yu. M. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation); Payusov, A. S.; Nadtochiy, A. M.; Zubov, F. I.; Korenev, V. V. [Russian Academy of Sciences, St. Petersburg Academic University-Nanotechnology Research and Education Center (Russian Federation)

    2013-08-15

    Heat dissipation under the high-speed modulation of quantum dot edge-emitting lasers is considered. It is shown that, for a given laser diode, there is a bias current at which the heat-to-bitrate ratio is minimized. Moreover, there exists a certain optimal optical loss of the laser cavity at which the lowest heat-to-bitrate ratio is provided for any design of edge-emitting lasers that can be fabricated from an epitaxial structure. The heat-to-bitrate ratio and the corresponding bitrate are numerically calculated and analytical expressions are derived. It is demonstrated that the heat-to-bitrate ratio of quantum dot edge-emitting lasers can be less than 0.4 pJ/bit at a bitrate exceeding 10 Gbit/s.

  11. Optimization of the design and mode of operation of a QD laser for reducing the heat-to-bitrate ratio

    International Nuclear Information System (INIS)

    Zhukov, A. E.; Savelyev, A. V.; Maximov, M. V.; Kryzhanovskaya, N. V.; Gordeev, N. Yu.; Shernyakov, Yu. M.; Payusov, A. S.; Nadtochiy, A. M.; Zubov, F. I.; Korenev, V. V.

    2013-01-01

    Heat dissipation under the high-speed modulation of quantum dot edge-emitting lasers is considered. It is shown that, for a given laser diode, there is a bias current at which the heat-to-bitrate ratio is minimized. Moreover, there exists a certain optimal optical loss of the laser cavity at which the lowest heat-to-bitrate ratio is provided for any design of edge-emitting lasers that can be fabricated from an epitaxial structure. The heat-to-bitrate ratio and the corresponding bitrate are numerically calculated and analytical expressions are derived. It is demonstrated that the heat-to-bitrate ratio of quantum dot edge-emitting lasers can be less than 0.4 pJ/bit at a bitrate exceeding 10 Gbit/s

  12. Conceptual design of a fast-ignition laser fusion reactor based on a dry wall chamber

    International Nuclear Information System (INIS)

    Ogawa, Y; Goto, T; Okano, K; Asaoka, Y; Hiwatari, R; Someya, Y

    2008-01-01

    The fast ignition is quite attractive for a compact laser fusion reactor, because a sufficiently high pellet gain is available with a small input energy. We designed an inertial fusion reactor based on Fast-ignition Advanced Laser fusion reactor CONcept, called FALCON-D, where a dry wall is employed for a chamber wall. A simple point model shows that the pellet gain G∼100 is available with laser energies of 350kJ for implosion, 50kJ for heating. This results in the fusion yield of 40 MJ in one shot. By increasing the repetition rate up to 30 Hz, the fusion power of 1.2 GWth becomes available. Plant system analysis shows the net electric power to be about 0.4 GWe In the fast ignition it is available to employ a low aspect ratio pellet, which is favorable for the stability during the implosion phase. Here the pellet aspect ratio is reduced to be 2 ∼ 4, and the optimization of the pulse shape for the implosion laser are carried out by using the 1-D hydrodynamic simulation code ILESTA-1D. A ferritic steel with a tungsten armour is employed for the chamber wall. The feasibility of this dry wall concept is studied from various engineering aspects such as surface melting, physical and chemical sputtering, blistering and exfoliation by helium retention, and thermo-mechanical fatigue, and it is found that blistering and exfoliation due to the helium retention and fatigue failure due to cyclic thermal load are major concerns. The cost analysis shows that the construction cost is moderate but the cost of electricity is slightly expensive

  13. Conceptual design of a fast-ignition laser fusion reactor based on a dry wall chamber

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Y [High Temperature Plasma Center, University of Tokyo, Chiba (Japan); Goto, T; Okano, K [Graduate School of Frontier Sciences, University of Tokyo, Chiba (Japan); Asaoka, Y; Hiwatari, R [Central Research Institute for Electric Power Industry, Komae, Tokyo (Japan); Someya, Y [Graduate School of Engineering, Musashi Institute of Technology, Tokyo (Japan)], E-mail: ogawa@ppl.k.u-tokyo.ac.jp

    2008-05-15

    The fast ignition is quite attractive for a compact laser fusion reactor, because a sufficiently high pellet gain is available with a small input energy. We designed an inertial fusion reactor based on Fast-ignition Advanced Laser fusion reactor CONcept, called FALCON-D, where a dry wall is employed for a chamber wall. A simple point model shows that the pellet gain G{approx}100 is available with laser energies of 350kJ for implosion, 50kJ for heating. This results in the fusion yield of 40 MJ in one shot. By increasing the repetition rate up to 30 Hz, the fusion power of 1.2 GWth becomes available. Plant system analysis shows the net electric power to be about 0.4 GWe In the fast ignition it is available to employ a low aspect ratio pellet, which is favorable for the stability during the implosion phase. Here the pellet aspect ratio is reduced to be 2 {approx} 4, and the optimization of the pulse shape for the implosion laser are carried out by using the 1-D hydrodynamic simulation code ILESTA-1D. A ferritic steel with a tungsten armour is employed for the chamber wall. The feasibility of this dry wall concept is studied from various engineering aspects such as surface melting, physical and chemical sputtering, blistering and exfoliation by helium retention, and thermo-mechanical fatigue, and it is found that blistering and exfoliation due to the helium retention and fatigue failure due to cyclic thermal load are major concerns. The cost analysis shows that the construction cost is moderate but the cost of electricity is slightly expensive.

  14. Conceptual design of a fast-ignition laser fusion reactor based on a dry wall chamber

    Science.gov (United States)

    Ogawa, Y.; Goto, T.; Okano, K.; Asaoka, Y.; Hiwatari, R.; Someya, Y.

    2008-05-01

    The fast ignition is quite attractive for a compact laser fusion reactor, because a sufficiently high pellet gain is available with a small input energy. We designed an inertial fusion reactor based on Fast-ignition Advanced Laser fusion reactor CONcept, called FALCON-D, where a dry wall is employed for a chamber wall. A simple point model shows that the pellet gain G~100 is available with laser energies of 350kJ for implosion, 50kJ for heating. This results in the fusion yield of 40 MJ in one shot. By increasing the repetition rate up to 30 Hz, the fusion power of 1.2 GWth becomes available. Plant system analysis shows the net electric power to be about 0.4 GWe In the fast ignition it is available to employ a low aspect ratio pellet, which is favorable for the stability during the implosion phase. Here the pellet aspect ratio is reduced to be 2 ~ 4, and the optimization of the pulse shape for the implosion laser are carried out by using the 1-D hydrodynamic simulation code ILESTA-1D. A ferritic steel with a tungsten armour is employed for the chamber wall. The feasibility of this dry wall concept is studied from various engineering aspects such as surface melting, physical and chemical sputtering, blistering and exfoliation by helium retention, and thermo-mechanical fatigue, and it is found that blistering and exfoliation due to the helium retention and fatigue failure due to cyclic thermal load are major concerns. The cost analysis shows that the construction cost is moderate but the cost of electricity is slightly expensive.

  15. Design of laser-aided diagnostics for the negative hydrogen ion source SPIDER

    International Nuclear Information System (INIS)

    Pasqualotto, R

    2012-01-01

    ITER nuclear fusion experiment requires additional heating via neutral beams by means of two injectors, delivering 16.5 MW each, up to one hour. This power level results from the neutralization of negative deuterium ions generated by an RF source and accelerated to 1 MeV. Such specifications have never been simultaneously achieved so far and therefore a test facility is being constructed at Consorzio RFX, to demonstrate the feasibility of a prototype neutral beam injector. The facility will host two experimental devices: SPIDER, a 100 kV negative hydrogen/deuterium RF source, full size prototype of the ITER source, and MITICA, a prototype of the full ITER injector. SPIDER will be devoted to optimize the extracted negative ion current density and its spatial uniformity and to minimize the co-extracted electron current. Negative hydrogen is mainly produced by conversion of hydrogen particles at the cesium coated surface of the plasma grid. The interplay of these two species is fundamental to understand and optimize the source performance. Two laser-aided diagnostics play an important role in measuring the negative hydrogen and cesium density: cavity ring down spectroscopy and laser absorption spectroscopy. Cavity ring down spectroscopy will use the photo-detachment process to measure the absolute line-of-sight integrated negative ion density in the extraction region of the source. Laser absorption spectroscopy will be employed to measure the line integrated neutral cesium density, allowing to study the cesium distribution in the source volume, during both the plasma and the vacuum phases. In this paper, the design of the laser-aided diagnostic systems on SPIDER is presented, supported by a review of results obtained in other operating experiments.

  16. Design of welding parameters for laser welding of thin-walled stainless steel tubes using numerical simulation

    Science.gov (United States)

    Nagy, M.; Behúlová, M.

    2017-11-01

    Nowadays, the laser technology is used in a wide spectrum of applications, especially in engineering, electronics, medicine, automotive, aeronautic or military industries. In the field of mechanical engineering, the laser technology reaches the biggest increase in the automotive industry, mainly due to the introduction of automation utilizing 5-axial movements. Modelling and numerical simulation of laser welding processes has been exploited with many advantages for the investigation of physical principles and complex phenomena connected with this joining technology. The paper is focused on the application of numerical simulation to the design of welding parameters for the circumferential laser welding of thin-walled exhaust pipes from theAISI 304 steel for automotive industry. Using the developed and experimentally verified simulation model for laser welding of tubes, the influence of welding parameters including the laser velocity from 30 mm.s-1 to 60 mm.s-1 and the laser power from 500 W to 1200 W on the temperature fields and dimensions of fusion zone was investigated using the program code ANSYS. Based on obtained results, the welding schedule for the laser beam welding of thin-walled tubes from the AISI 304 steel was suggested.

  17. SIMULATION OF THE Ku-BAND RADAR ALTIMETER SEA ICE EFFECTIVE SCATTERING SURFACE

    DEFF Research Database (Denmark)

    Tonboe, Rasmus; Andersen, Søren; Pedersen, Leif Toudal

    2006-01-01

    A radiative transfer model is used to simulate the sea ice radar altimeter effective scattering surface variability as a function of snow depth and density. Under dry snow conditions without layering these are the primary snow parameters affecting the scattering surface variability. The model is ...

  18. Design of pre-optics for laser guide star wavefront sensor for the ELT

    Science.gov (United States)

    Muslimov, Eduard; Dohlen, Kjetil; Neichel, Benoit; Hugot, Emmanuel

    2017-12-01

    In the present paper, we consider the optical design of a zoom system for the active refocusing in laser guide star wavefront sensors. The system is designed according to the specifications coming from the Extremely Large Telescope (ELT)-HARMONI instrument, the first-light, integral field spectrograph for the European (E)-ELT. The system must provide a refocusing of the laser guide as a function of telescope pointing and large decentring of the incoming beam. The system considers four moving lens groups, each of them being a doublet with one aspherical surface. The advantages and shortcomings of such a solution in terms of the component displacements and complexity of the surfaces are described in detail. It is shown that the system can provide the median value of the residual wavefront error of 13.8-94.3 nm and the maximum value <206 nm, while the exit pupil distortion is 0.26-0.36% for each of the telescope pointing directions.

  19. Large field distributed aperture laser semiactive angle measurement system design with imaging fiber bundles.

    Science.gov (United States)

    Xu, Chunyun; Cheng, Haobo; Feng, Yunpeng; Jing, Xiaoli

    2016-09-01

    A type of laser semiactive angle measurement system is designed for target detecting and tracking. Only one detector is used to detect target location from four distributed aperture optical systems through a 4×1 imaging fiber bundle. A telecentric optical system in image space is designed to increase the efficiency of imaging fiber bundles. According to the working principle of a four-quadrant (4Q) detector, fiber diamond alignment is adopted between an optical system and a 4Q detector. The structure of the laser semiactive angle measurement system is, we believe, novel. Tolerance analysis is carried out to determine tolerance limits of manufacture and installation errors of the optical system. The performance of the proposed method is identified by computer simulations and experiments. It is demonstrated that the linear region of the system is ±12°, with measurement error of better than 0.2°. In general, this new system can be used with large field of view and high accuracy, providing an efficient, stable, and fast method for angle measurement in practical situations.

  20. Laser surface modification of electrically conductive fabrics: Material performance improvement and design effects

    Science.gov (United States)

    Tunakova, Veronika; Hrubosova, Zuzana; Tunak, Maros; Kasparova, Marie; Mullerova, Jana

    2018-01-01

    Development of lightweight flexible materials for electromagnetic interference shielding has obtained increased attention in recent years particularly for clothing, textiles in-house use and technical applications especially in areas of aircraft, aerospace, automobiles and flexible electronics such as portable electronics and wearable devices. There are many references in the literature concerning development and investigation of electromagnetic shielding lightweight flexible materials especially textile based with different electrically conductive additives. However, only little attention is paid to designing and enhancing the properties of these special fabrics by textile finishing processes. Laser technology applied as a physical treatment method is becoming very popular and can be used in different applications to make improvement and even overcome drawbacks of some of the traditional processes. The main purpose of this study is firstly to analyze the possibilities of transferring design onto the surface of electrically conductive fabrics by laser beam and secondly to study of effect of surface modification degree on performance of conductive fabric including electromagnetic shielding ability and mechanical properties. Woven fabric made of yarns containing 10% of extremely thin stainless steel fiber was used as a conductive substrate.

  1. Performance Optimization Design for a High-Speed Weak FBG Interrogation System Based on DFB Laser.

    Science.gov (United States)

    Yao, Yiqiang; Li, Zhengying; Wang, Yiming; Liu, Siqi; Dai, Yutang; Gong, Jianmin; Wang, Lixin

    2017-06-22

    A performance optimization design for a high-speed fiber Bragg grating (FBG) interrogation system based on a high-speed distributed feedback (DFB) swept laser is proposed. A time-division-multiplexing sensor network with identical weak FBGs is constituted to realize high-capacity sensing. In order to further improve the multiplexing capacity, a waveform repairing algorithm is designed to extend the dynamic demodulation range of FBG sensors. It is based on the fact that the spectrum of an FBG keeps stable over a long period of time. Compared with the pre-collected spectra, the distorted spectra waveform are identified and repaired. Experimental results show that all the identical weak FBGs are distinguished and demodulated at the speed of 100 kHz with a linearity of above 0.99, and the range of dynamic demodulation is extended by 40%.

  2. Performance Optimization Design for a High-Speed Weak FBG Interrogation System Based on DFB Laser

    Directory of Open Access Journals (Sweden)

    Yiqiang Yao

    2017-06-01

    Full Text Available A performance optimization design for a high-speed fiber Bragg grating (FBG interrogation system based on a high-speed distributed feedback (DFB swept laser is proposed. A time-division-multiplexing sensor network with identical weak FBGs is constituted to realize high-capacity sensing. In order to further improve the multiplexing capacity, a waveform repairing algorithm is designed to extend the dynamic demodulation range of FBG sensors. It is based on the fact that the spectrum of an FBG keeps stable over a long period of time. Compared with the pre-collected spectra, the distorted spectra waveform are identified and repaired. Experimental results show that all the identical weak FBGs are distinguished and demodulated at the speed of 100 kHz with a linearity of above 0.99, and the range of dynamic demodulation is extended by 40%.

  3. An infrared free-electron laser for the Chemical Dynamics Research Laboratory. Design report

    Energy Technology Data Exchange (ETDEWEB)

    Vaughan, D. [comp.

    1992-04-01

    This document describes a free-electron laser (FEL) proposed as part of the Chemical Dynamics Research Laboratory (CDRL), a user facility that also incorporates several advanced lasers of conventional design and two beamlines for the ALS. The FEL itself addresses the needs of the chemical sciences community for a high-brightness, tunable source covering a broad region of the infrared spectrum -- from 3 to 50 {mu}m. All of these sources, together with a variety of sophisticated experimental stations, will be housed in a new building to be located adjacent to the ALS. The radiation sources can be synchronized to permit powerful two-color, pump-probe experiments that will further our fundamental understanding of chemical dynamics at the molecular level, especially those aspects relevant to practical issues in combustion chemistry. The technical approach adopted in this design makes use of superconducting radiofrequency (SCRF) accelerating structures. The primary motivation for adopting this approach was to meet the user requirement for wavelength stability equal to one part in 10{sup 4}. Previous studies concluded that a wavelength stability of only one part in 10{sup 3} could be achieved with currently available room-temperature technology. In addition, the superconducting design operates in a continuous-wave (cw) mode and hence offers considerably higher average optical output power. It also allows for various pulse-gating configurations that will permit simultaneous multiuser operations. A summary of the comparative performance attainable with room-temperature and superconducting designs is given. The FEL described in this report provides a continuous train of 30-ps micropulses, with 100{mu}J of optical energy per micropulse, at a repetition rate of 6.1 MHz. The device can also deliver pulses at a cw repetition rate of 12.2 MHz, with a peak power of 50 {mu}J per micropulse. 70 ref.

  4. Design of a solar-pumped frequency-doubled 532 nm Nd:YVO4 laser

    Science.gov (United States)

    Kittiboonanan, P.; Putchana, W.; Deeudomand, M.; Ratanavis, A.

    2017-09-01

    During the last year we have made progresson a development of a frequency-doubled 532 nm Nd:YVO4 laser pumped by solar light. The research aimed to demonstrate solar pumped lasers consisting of the optically contracted Nd:YVO4 crystal and KTP crystal with a system of laser mirrors deposited onto crystal sides. The Cassegrain reflector is used as the configuration. This solar pumped laser system is appealing for a variety applications including laser communication, imaging and defense applications.

  5. Reliability of Wind Speed Data from Satellite Altimeter to Support Wind Turbine Energy

    Science.gov (United States)

    Uti, M. N.; Din, A. H. M.; Omar, A. H.

    2017-10-01

    Satellite altimeter has proven itself to be one of the important tool to provide good quality information in oceanographic study. Nowadays, most countries in the world have begun in implementation the wind energy as one of their renewable energy for electric power generation. Many wind speed studies conducted in Malaysia using conventional method and scientific technique such as anemometer and volunteer observing ships (VOS) in order to obtain the wind speed data to support the development of renewable energy. However, there are some limitations regarding to this conventional method such as less coverage for both spatial and temporal and less continuity in data sharing by VOS members. Thus, the aim of this research is to determine the reliability of wind speed data by using multi-mission satellite altimeter to support wind energy potential in Malaysia seas. Therefore, the wind speed data are derived from nine types of satellite altimeter starting from year 1993 until 2016. Then, to validate the reliability of wind speed data from satellite altimeter, a comparison of wind speed data form ground-truth buoy that located at Sabah and Sarawak is conducted. The validation is carried out in terms of the correlation, the root mean square error (RMSE) calculation and satellite track analysis. As a result, both techniques showing a good correlation with value positive 0.7976 and 0.6148 for point located at Sabah and Sarawak Sea, respectively. It can be concluded that a step towards the reliability of wind speed data by using multi-mission satellite altimeter can be achieved to support renewable energy.

  6. The impact of the snow cover on sea-ice thickness products retrieved by Ku-band radar altimeters

    Science.gov (United States)

    Ricker, R.; Hendricks, S.; Helm, V.; Perovich, D. K.

    2015-12-01

    Snow on sea ice is a relevant polar climate parameter related to ocean-atmospheric interactions and surface albedo. It also remains an important factor for sea-ice thickness products retrieved from Ku-band satellite radar altimeters like Envisat or CryoSat-2, which is currently on its mission and the subject of many recent studies. Such satellites sense the height of the sea-ice surface above the sea level, which is called sea-ice freeboard. By assuming hydrostatic equilibrium and that the main scattering horizon is given by the snow-ice interface, the freeboard can be transformed into sea-ice thickness. Therefore, information about the snow load on hemispherical scale is crucial. Due to the lack of sufficient satellite products, only climatological values are used in current studies. Since such values do not represent the high variability of snow distribution in the Arctic, they can be a substantial contributor to the total sea-ice thickness uncertainty budget. Secondly, recent studies suggest that the snow layer cannot be considered as homogenous, but possibly rather featuring a complex stratigraphy due to wind compaction and/or ice lenses. Therefore, the Ku-band radar signal can be scattered at internal layers, causing a shift of the main scattering horizon towards the snow surface. This alters the freeboard and thickness retrieval as the assumption that the main scattering horizon is given by the snow-ice interface is no longer valid and introduces a bias. Here, we present estimates for the impact of snow depth uncertainties and snow properties on CryoSat-2 sea-ice thickness retrievals. We therefore compare CryoSat-2 freeboard measurements with field data from ice mass-balance buoys and aircraft campaigns from the CryoSat Validation Experiment. This unique validation dataset includes airborne laser scanner and radar altimeter measurements in spring coincident to CryoSat-2 overflights, and allows us to evaluate how the main scattering horizon is altered by the

  7. The influence of rain and clouds on a satellite dual frequency radar altimeter system operating at 13 and 35 GHz

    Science.gov (United States)

    Walsh, E. J.; Monaldo, F. M.; Goldhirsh, J.

    1983-01-01

    The effects of inhomogeneous spatial attenuation resulting from clouds and rain on the altimeter estimate of the range to mean sea level are modelled. It is demonstrated that typical cloud and rain attenuation variability at commonly expected spatial scales can significantly degrade altimeter range precision. Rain cell and cloud scale sizes and attenuations are considered as factors. The model simulation of altimeter signature distortion is described, and the distortion of individual radar pulse waveforms by different spatial scales of attenuation is considered. Examples of range errors found for models of a single cloud, a rain cell, and cloud streets are discussed.

  8. Designing symmetric polar direct drive implosions on the Omega laser facility

    Energy Technology Data Exchange (ETDEWEB)

    Krasheninnikova, Natalia S.; Cobble, James A.; Murphy, Thomas J.; Tregillis, Ian L.; Bradley, Paul A.; Hakel, Peter; Hsu, Scott C.; Kyrala, George A.; Obrey, Kimberly A.; Schmitt, Mark J.; Baumgaertel, Jessica A.; Batha, Steven H. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2014-04-15

    Achieving symmetric capsule implosions with Polar Direct Drive [S. Skupsky et al., Phys. Plasmas 11, 2763 (2004); R. S. Craxton et al., Phys. Plasmas 12, 056304 (2005); F. J. Marshall et al., J. Phys. IV France 133, 153–157 (2006)] has been explored during recent Defect Induced Mix Experiment campaign on the Omega facility at the Laboratory for Laser Energetics. To minimize the implosion asymmetry due to laser drive, optimized laser cone powers, as well as improved beam pointings, were designed using 3D radiation-hydrodynamics code HYDRA [M. M. Marinak et al., Phys. Plasmas 3, 2070 (1996)]. Experimental back-lit radiographic and self-emission images revealed improved polar symmetry and increased neutron yield which were in good agreement with 2D HYDRA simulations. In particular, by reducing the energy in Omega's 21.4° polar rings by 16.75%, while increasing the energy in the 58.9° equatorial rings by 8.25% in such a way as to keep the overall energy to the target at 16 kJ, the second Legendre mode (P{sub 2}) was reduced by a factor of 2, to less than 4% at bang time. At the same time the neutron yield increased by 62%. The polar symmetry was also improved relative to nominal DIME settings by a more radical repointing of OMEGA's 42.0° and 58.9° degree beams, to compensate for oblique incidence and reduced absorption at the equator, resulting in virtually no P{sub 2} around bang time and 33% more yield.

  9. Fiber coupled diode laser beam parameter product calculation and rules for optimized design

    Science.gov (United States)

    Wang, Zuolan; Segref, Armin; Koenning, Tobias; Pandey, Rajiv

    2011-03-01

    The Beam Parameter Product (BPP) of a passive, lossless system is a constant and cannot be improved upon but the beams may be reshaped for enhanced coupling performance. The function of the optical designer of fiber coupled diode lasers is to preserve the brightness of the diode sources while maximizing the coupling efficiency. In coupling diode laser power into fiber output, the symmetrical geometry of the fiber core makes it highly desirable to have symmetrical BPPs at the fiber input surface, but this is not always practical. It is therefore desirable to be able to know the 'diagonal' (fiber) BPP, using the BPPs of the fast and slow axes, before detailed design and simulation processes. A commonly used expression for this purpose, i.e. the square root of the sum of the squares of the BPPs in the fast and slow axes, has been found to consistently under-predict the fiber BPP (i.e. better beam quality is predicted than is actually achievable in practice). In this paper, using a simplified model, we provide the proof of the proper calculation of the diagonal (i.e. the fiber) BPP using BPPs of the fast and slow axes as input. Using the same simplified model, we also offer the proof that the fiber BPP can be shown to have a minimum (optimal) value for given diode BPPs and this optimized condition can be obtained before any detailed design and simulation are carried out. Measured and simulated data confirms satisfactory correlation between the BPPs of the diode and the predicted fiber BPP.

  10. Design and Development of Intracavity Optical Parametric Oscillator-based Eye Safe Laser Operating at 20 Hz without Forced Air Cooling

    OpenAIRE

    Atul Bhardwaj; Lalita Agrawal; A. K. Maini

    2013-01-01

    In this paper we report the design and development of an electro-optically Q-switched diode pumped Nd:YAG laser with intracavity optical parametric oscillator, generating ~ 5 ns laser pulses of ~8 mJ energy at eye safe wavelength of 1534 nm. A Z-shaped laser resonator has been designed with porro prism end reflector in Q-switch arm containing RTP Q-Switch and a suitably oriented waveplate. The gain arm consists of a Ø3 x 72 mm Nd: YAG laser rod, pumped from one side by 3 x 5 bar laser diode a...

  11. Cost reduction study for the LANL KrF laser-driven LMF design

    International Nuclear Information System (INIS)

    1989-01-01

    This report is in fulfillment of the deliverable requirements for the optical components portions of the LANL-KrF Laser-Driven LMF Design Cost Reduction Study. This report examines the future cost reductions that may accrue through the use of mass production, innovative manufacturing techniques, and new materials. Results are based on data collection and survey of optical component manufacturers, BDM experience, and existing cost models. These data provide a good representation of current methods and technologies from which future estimates can be made. From these data, a series of scaling relationships were developed to project future costs for a selected set of technologies. The scaling relationships are sensitive to cost driving parameters such as size and surface figure requirements as well as quantity requirements, production rate, materials, and manufacturing processes. In addition to the scaling relationships, descriptions of the selected processes were developed along with graphical representations of the processes. This report provides a useful tool in projecting the costs of advanced laser concepts at the component level of detail. A mix of the most diverse yet comparable technologies was chosen for this study. This yielded a useful, yet manageable number of variables to examine. The study has resulted in a first-order cost model which predicts the relative cost behavior of optical components within different variable constraints

  12. Experimental validation of a newly designed 6 degrees of freedom scanning laser head: Application to three-dimensional beam structure

    International Nuclear Information System (INIS)

    Di Maio, D.; Copertaro, E.

    2013-01-01

    A new scanning laser head is designed to use single Laser Doppler Vibrometer (LDV) for performing measurements up to 6 degrees of freedom (DOF) at a target. The scanning head is supported by a rotating hollow shaft, which allows the laser beam to travel up to the scanning head from an opposite direction where an LDV is set up. The scanning head is made of a set of two mirrors, which deflects the laser beam with an angle so that the rotation of the scanning head produces a conical scan. When measurements are performed at the focal point of the conical scan then three translational vibration components can be measured, otherwise the very small circle scan, before and after the focal point, can measure up to 6 degrees of freedom, including three translations and three rotations. This paper presents the 6DOF scanning head and the measurements of 3D operational deflection shapes of a test structure

  13. Extreme triple asymmetric (ETAS) epitaxial designs for increased efficiency at high powers in 9xx-nm diode lasers

    Science.gov (United States)

    Kaul, T.; Erbert, G.; Maaßdorf, A.; Martin, D.; Crump, P.

    2018-02-01

    Broad area lasers that are tailored to be most efficient at the highest achievable optical output power are sought by industry to decrease operation costs and improve system performance. Devices using Extreme-Double-ASymmetric (EDAS) epitaxial designs are promising candidates for improved efficiency at high optical output powers due to low series resistance, low optical loss and low carrier leakage. However, EDAS designs leverage ultra-thin p-side waveguides, meaning that the optical mode is shifted into the n-side waveguide, resulting in a low optical confinement in the active region, low gain and hence high threshold current, limiting peak performance. We introduce here explicit design considerations that enable EDAS-based devices to be developed with increased optical confinement in the active layer without changing the p-side layer thicknesses. Specifically, this is realized by introducing a third asymmetric component in the vicinity of the quantum well. We call this approach Extreme-Triple-ASymmetric (ETAS) design. A series of ETAS-based vertical designs were fabricated into broad area lasers that deliver up to 63% power conversion efficiency at 14 W CW optical output power from a 100 μm stripe laser, which corresponds to the operation point of a kW optical output power in a laser bar. The design process, the impact of structural changes on power saturation mechanisms and finally devices with improved performance will be presented.

  14. Design of a high-gain laser diode-array pumped Nd:YAG alternating precessive slab amplifier (APS amplifier)

    Science.gov (United States)

    Coyle, D. B.

    1991-01-01

    In the design of space-qualifiable laser systems for ranging and altimetry, such as NASA's Geodynamic Laser Ranging System (GLRS), the transmitter must be kept small, powerful yet efficient, and must consist of as few components as possible. A novel preamplifier design is examined which requires no external beam steering optics, yielding a compact component with simple alignment procedures. The gains achieved are comparable to multipass zigzag amplifiers using two or more sets of external optics for extra passes through the amplifying medium.

  15. Design, development, optimization of 40GW/300-800 ps Nd: glass laser system and study of matter at extreme temperature and pressure

    International Nuclear Information System (INIS)

    Chaurasia, S.; Munda, D.S.; Murali, C.G.; Gupta, N.K.; Dhareshwar, L.J.; Vijayan, Rajasree; Narayan, B.S.

    2008-02-01

    Laser Plasma interaction studies and experiments related to laser driven shocks as well as inertial confinement fusion (ICF) has resulted in an ever increasing demand of development of high power nanosecond and sub-nanosecond laser. A 12J/300-800 ps (40 GW) laser chain has been developed at our laboratory and it is planned to upgrade it to 30 Joules. In this report we describe design and development of 12J/300-800 ps (40 GW) laser system built for laser-plasma related and laser driven shock related work. The laser is having focusable intensity of the order of 1014 W/cm 2 which is used to carry out various experiments in the frontier area of laser produced plasma. The development work described in this report discusses the design and developments of various subsystem such as Laser amplifiers, spatial filters and Faraday isolator, experimental chamber. The necessary electronics also has been described in brief. Theoretical simulation models developed over a period of time to analyze the laser plasma experiments are also summarized. A number of experiments have been carried out in the existing laser chain. Some of these experiments are also presented in the report. Enhancement of x-ray emission (better conversion efficiency) is prime task for the indirect drive inertial confinement fusion. We have done experiments to see the enhancement using various target geometry and the laser focusing geometry and a summary of these experiments is presented. (author)

  16. Design of a chamber for deposit of thin films by laser ablation; Diseno de una camara para el deposito de peliculas delgadas por ablacion laser

    Energy Technology Data Exchange (ETDEWEB)

    Chirino O, S

    2001-07-01

    The present work has as purpose to design a vacuum chamber, to the one that is denominated chamber of ablation, in which were carried out deposits of thin films using the well-known technique as laser ablation. To fulfill the purpose, the work has been distributed in the following way: in the chapter 1 there are discussed the generalities of the technique of ablation laser for the obtaining of materials in form of thin film, in the chapter 2 the basic concepts of the vacuum technology are mentioned that includes among other things, systems to produce vacuum and vacuum gages and in the chapter 3 the design of the chamber is presented with the accessories and specific systems. (Author)

  17. Preliminary design and neutronic analysis of a laser fusion driven actinide waste burning hybrid reactor

    International Nuclear Information System (INIS)

    Berwald, D.H.; Duderstadt, J.J.

    1979-01-01

    The laser fusion driven actinide waste burner (LDAB) system investigated uses partitioned fission power reactor generated actinide wastes dissolved in a molten tin alloy as feed material (or fuel). A novel fuel processing concept based on the high-temperature precipitation of ''actinide--nitrides'' from a liquid tin solution is proposed. This concept will allow for fission product removal to be performed entirely within the device at high burnup. No attempt has been made to optimize this system, but potential performance is impressive. The equilibrium LDAB design consumes 7.6 MT/y of actinide waste. This corresponds to the waste output from 136 light water reactors [1000 MW (electric)]. The mean life of an actinide atom in the LDAB is only 4.5 y; and actinides, once charged to the LDAB, might be reprocessed fewer times during irradiation than in previously proposed systems

  18. Design of the miniaturized free electron laser module as an efficient source of the THz waves

    International Nuclear Information System (INIS)

    Kim, Young Chul; Ahn, Seong Joon; Kim, Ho Seob; Kim, Dae-Wook; Ahn, Seungjoon

    2011-01-01

    Since the tremendous potential of the THz wave for the bio-technological applications has been found, there has been a lot of interest paid to development of the THz-wave sources. The miniaturized free electron laser (FEL) module based on the microcolumn can be a very convenient THz wave emitter because of its compactness. In this work, we tried to design the miniaturized FEL module to achieve the optimized electron beam (e-beam) trajectory in the module by using 3D simulation tool. We found that the accelerator bias, the length and radius of the limiting aperture were important parameters to obtain the strong and parallel e-beam. We have also proposed the ring-type grids to get more symmetrical behavior of the e-beam in the wiggler.

  19. Design of the miniaturized free electron laser module as an efficient source of the THz waves

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Chul [Department of Optometry, Eulji University, 212 Yangji-dong, Sujeong-gu, Seongnam-si, Gyeonggi-do 461-713 (Korea, Republic of); Ahn, Seong Joon [Department of I and C Engineering, Sun Moon University, Tangjeong-myeon, Asan-si, Chungnam 336-708 (Korea, Republic of); Kim, Ho Seob; Kim, Dae-Wook [Department of Information Display, Sun Moon University, 100 Kalsan-ri, Tangjeong-myun, Asan-si, Chungnam 336-708 (Korea, Republic of); Ahn, Seungjoon, E-mail: sjan@sunmoon.ac.kr [Department of Information Display, Sun Moon University, 100 Kalsan-ri, Tangjeong-myun, Asan-si, Chungnam 336-708 (Korea, Republic of)

    2011-10-21

    Since the tremendous potential of the THz wave for the bio-technological applications has been found, there has been a lot of interest paid to development of the THz-wave sources. The miniaturized free electron laser (FEL) module based on the microcolumn can be a very convenient THz wave emitter because of its compactness. In this work, we tried to design the miniaturized FEL module to achieve the optimized electron beam (e-beam) trajectory in the module by using 3D simulation tool. We found that the accelerator bias, the length and radius of the limiting aperture were important parameters to obtain the strong and parallel e-beam. We have also proposed the ring-type grids to get more symmetrical behavior of the e-beam in the wiggler.

  20. LINAC DESIGN FOR AN ARRAY OF SOFT X-RAY FREE ELECTRON LASERS

    International Nuclear Information System (INIS)

    Zholents, Alexander A.; Kur, E.; Penn, G.; Qiang, Ji; Venturini, M.; Wells, R. P.

    2008-01-01

    The design of the linac delivering electron bunches into ten independent soft x-ray free electron lasers (FELs) producing light at 1 nm and longer wavelengths is presented. The bunch repetition rate in the linac is 1 MHz and 100 kHz in each of ten FEL beam lines. Various issues regarding machine layout and lattice, bunch compression, collimation, and the beam switch yard are discussed. Particular attention is given to collective effects. A demanding goal is to preserve both a low beam slice emittance and low slice energy spread during acceleration, bunch compression and distribution of the electron bunches into the array of FEL beamlines. Detailed studies of the effect of the electron beam microbunching caused by longitudinal space-charge forces and coherent synchrotron radiation (CSR) have been carried out and their results are presented

  1. Optical design of multi-multiple expander structure of laser gas analysis and measurement device

    Science.gov (United States)

    Fu, Xiang; Wei, Biao

    2018-03-01

    The installation and debugging of optical circuit structure in the application of carbon monoxide distributed laser gas analysis and measurement, there are difficult key technical problems. Based on the three-component expansion theory, multi-multiple expander structure with expansion ratio of 4, 5, 6 and 7 is adopted in the absorption chamber to enhance the adaptability of the installation environment of the gas analysis and measurement device. According to the basic theory of aberration, the optimal design of multi-multiple beam expander structure is carried out. By using image quality evaluation method, the difference of image quality under different magnifications is analyzed. The results show that the optical quality of the optical system with the expanded beam structure is the best when the expansion ratio is 5-7.

  2. Selective Laser Melting of Hot Gas Turbine Components: Materials, Design and Manufacturing Aspects

    DEFF Research Database (Denmark)

    Goutianos, Stergios

    2017-01-01

    are built additively to nearly net shape. This allows the fabrication of arbitrary complex geometries that cannot be made by conventional manufacturing techniques. However, despite the powerful capabilities of SLM, a number of issues (e.g. part orientation, support structures, internal stresses), have......Selective Laser Melting (SLM) allows the design and manufacturing of novel parts and structures with improved performance e.g. by incorporating complex and more efficient cooling schemes in hot gas turbine parts. In contrast to conventional manufacturing of removing material, with SLM parts...... to be considered in order to manufacture cost-effective and high quality parts at an industrial scale. These issues are discussed in the present work from an engineering point of view with the aim to provide simple quidelines to produce high quality SLM parts....

  3. Design of laser diode driver with constant current and temperature control system

    Science.gov (United States)

    Wang, Ming-cai; Yang, Kai-yong; Wang, Zhi-guo; Fan, Zhen-fang

    2017-10-01

    A laser Diode (LD) driver with constant current and temperature control system is designed according to the LD working characteristics. We deeply researched the protection circuit and temperature control circuit based on thermos-electric cooler(TEC) cooling circuit and PID algorithm. The driver could realize constant current output and achieve stable temperature control of LD. Real-time feedback control method was adopted in the temperature control system to make LD work on its best temperature point. The output power variety and output wavelength shift of LD caused by current and temperature instability were decreased. Furthermore, the driving current and working temperature is adjustable according to specific requirements. The experiment result showed that the developed LD driver meets the characteristics of LD.

  4. Opto-mechanical design and gravity-deformation analysis on optical telescope in laser communication system

    Science.gov (United States)

    Fu, Sen; Du, Jindan; Song, Yiwei; Gao, Tianyu; Zhang, Daqing; Wang, Yongzhi

    2017-11-01

    In space laser communication, optical antennas are one of the main components and the precision of optical antennas is very high. In this paper, it is based on the R-C telescope and it is carried out that the design and simulation of optical lens and supporting truss, according to the parameters of the systems. And a finite element method (FEM) was used to analyze the deformation of the optical lens. Finally, the Zernike polynomial was introduced to fit the primary mirror with a diameter of 250mm. The objective of this study is to determine whether the wave-front aberration of the primary mirror can meet the imaging quality. The results show that the deterioration of the imaging quality caused by the gravity deformation of primary and secondary mirrors. At the same time, the optical deviation of optical antenna increase with the diameter of the pupil.

  5. Design and Implementation of a Laser-Based Ammonia Breath Sensor for Medical Applications

    KAUST Repository

    Owen, Kyle

    2012-06-01

    Laser-based sensors can be used as non-invasive monitoring tools to measure parts per billion (ppb) levels of trace gases. Ammonia sensors are useful for applications in environmental pollutant monitoring, atmospheric and combustion kinetic studies, and medical diagnostics. This sensor was specifically designed to measure ammonia in exhaled breath to be used as a medical diagnostic and monitoring tool, however, it can also be extended for use in other applications. Although ammonia is a naturally occurring species in exhaled breath, abnormally elevated levels can be an indication of adverse medical conditions. Laser-based breath diagnostics have many benefits since they are cost effective, non-invasive, painless, real time monitors. They have the potential to improve the quality of medical care by replacing currently used blood tests and providing immediate feedback to physicians. This sensor utilizes a Quantum Cascade Laser and Wavelength Modulation Spectroscopy with second harmonic normalized by first harmonic detection in a 76 m multi-pass absorption cell to measure ppb levels of ammonia with improved sensitivity over previous sensors. Initial measurements to determine the ammonia absorption line parameters were performed using direct absorption spectroscopy. This is the first experimental study of the ammonia absorption line transitions near 1103.46 cm1 with absorption spectroscopy. The linestrengths were measured with uncertainties less than 10%. The collisional broadening coefficients for each of the ammonia lines with nitrogen, oxygen, water vapor, and carbon dioxide were also measured, many of which had uncertainties less than 5%. The sensor was characterized to show a detectability limit of 10 ppb with an uncertainty of less than 5% at typical breath ammonia levels. Initial breath test results showed that some of the patients with chronic kidney disease had elevated ammonia levels while others had ammonia levels in the same range as expected for healthy

  6. Design and Analysis of Enhanced Modulation Response in Integrated Coupled Cavities DBR Lasers Using Photon-Photon Resonance

    Directory of Open Access Journals (Sweden)

    Paolo Bardella

    2016-01-01

    Full Text Available In the last few decades, various solutions have been proposed to increase the modulation bandwidth and, consequently, the transmission bit-rate of semiconductor lasers. In this manuscript, we discuss a design procedure for a recently proposed laser cavity realized with the monolithic integration of two distributed Bragg reflector (DBR lasers allowing one to extend the modulation bandwidth. Such an extension is obtained introducing in the dynamic response a photon-photon resonance (PPR at a frequency higher than the modulation bandwidth of the corresponding single-section laser. Design guidelines will be proposed, and dynamic small and large signal simulations results, calculated using a finite difference traveling wave (FDTW numerical simulator, will be discussed to confirm the design results. The effectiveness of the design procedure is verified in a structure with PPR frequency at 35 GHz allowing one to obtain an open eye diagram for a non-return-to-zero (NRZ digital signal up to 80 GHz . Furthermore, the investigation of the rich dynamics of this structure shows that with proper bias conditions, it is possible to obtain also a tunable self-pulsating signal in a frequency range related to the PPR design.

  7. Offshore limit of coastal ocean variability identified from hydrography and altimeter data in the eastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Antony, M.K.; Swamy, G.N.; Somayajulu, Y.K.

    In this communication, we describe a hitherto-unknown offshore limit to the coastal ocean variability signatures away from the continental shelf in the eastern Arabian Sea, based on hydrographic observations and satellite altimeter (TOPEX...

  8. Efficacy of Laser Therapy in Ankle Sprains : Design of a Randomized Clinical Trial

    NARCIS (Netherlands)

    de Bie, Robert A.; de Vet, Henrica CW; Knipschild, Paul G.; van den Wildenberg, Frans AJM; Lenssen, Ton F.; Bouter, Lex

    1997-01-01

    Studies on low intensity 904 nm laser therapy in the treatment of musculoskeletal disorders show conflicting results. Yet, on the basis of a systematic review we concluded that 904 nm laser therapy for musculoskeletal disorders seems to be promising, when compared to placebo laser therapy. Quick

  9. Laser penetration spike welding : A microlaser welding technique enabling novel product designs and constructions

    NARCIS (Netherlands)

    Dijken, D.K; Hoving, W.; de Hosson, J.T.M.

    A novel method for laser penetration microspot welding of sheet metal is presented. With this so called "laser spike-welding," large gap tolerances are allowed. Depending on the ratio of laser spot radius to top plate thickness, gaps of 100% of the top layer thickness and more can be bridged. With

  10. Application of additive laser technologies in the gas turbine blades design process

    Science.gov (United States)

    Shevchenko, I. V.; Rogalev, A. N.; Osipov, S. K.; Bychkov, N. M.; Komarov, I. I.

    2017-11-01

    An emergence of modern innovative technologies requires delivering new and modernization existing design and production processes. It is especially relevant for designing the high-temperature turbines of gas turbine engines, development of which is characterized by a transition to higher parameters of working medium in order to improve their efficient performance. A design technique for gas turbine blades based on predictive verification of thermal and hydraulic models of their cooling systems by testing of a blade prototype fabricated using the selective laser melting technology was presented in this article. Technique was proven at the time of development of the first stage blade cooling system for the high-pressure turbine. An experimental procedure for verification of a thermal model of the blades with convective cooling systems based on the comparison of heat-flux density obtained from the numerical simulation data and results of tests in a liquid-metal thermostat was developed. The techniques makes it possible to obtain an experimentally tested blade version and to exclude its experimental adjustment after the start of mass production.

  11. Assessing the impact of multiple altimeter missions and Argo in a global eddy-permitting data assimilation system

    Science.gov (United States)

    Verrier, Simon; Le Traon, Pierre-Yves; Remy, Elisabeth

    2017-12-01

    A series of observing system simulation experiments (OSSEs) is carried out with a global data assimilation system at 1/4° resolution using simulated data derived from a 1/12° resolution free-run simulation. The objective is to not only quantify how well multiple altimeter missions and Argo profiling floats can constrain the global ocean analysis and 7-day forecast at 1/4° resolution but also to better understand the sensitivity of results to data assimilation techniques used in Mercator Ocean operational systems. The impact of multiple altimeter data is clearly evidenced even at a 1/4° resolution. Seven-day forecasts of sea level and ocean currents are significantly improved when moving from one altimeter to two altimeters not only on the sea level, but also on the 3-D thermohaline structure and currents. In high-eddy-energy regions, sea level and surface current 7-day forecast errors when assimilating one altimeter data set are respectively 20 and 45 % of the error of the simulation without assimilation. Seven-day forecasts of sea level and ocean currents continue to be improved when moving from one altimeter to two altimeters with a relative error reduction of almost 30 %. The addition of a third altimeter still improves the 7-day forecasts even at this medium 1/4° resolution and brings an additional relative error reduction of about 10 %. The error level of the analysis with one altimeter is close to the 7-day forecast error level when two or three altimeter data sets are assimilated. Assimilating altimeter data also improves the representation of the 3-D ocean fields. The addition of Argo has a major impact on improving temperature and demonstrates the essential role of Argo together with altimetry in constraining a global data assimilation system. Salinity fields are only marginally improved. Results derived from these OSSEs are consistent with those derived from experiments with real data (observing system evaluations, OSEs) but they allow for more

  12. Design of a bolometer for total-energy measurement of the linear coherent light source pulsed X-ray laser

    International Nuclear Information System (INIS)

    Friedrich, S.; Li, L.; Ott, L.L.; Kolgani, Rajeswari M.; Yong, G.J.; Ali, Z.A.; Drury, O.B.; Ables, E.; Bionta, R.M.

    2006-01-01

    We are developing a cryogenic bolometer to measure the total energy of the linear coherent light source (LCLS) free electron X-ray laser to be built at the Stanford Linear Accelerator Center. The laser will produce ultrabright X-ray pulses in the energy range between 0.8 and 8 keV with ∼10 12 photons per ∼200 fs pulse at a repeat interval of 8 ms, and will be accompanied by a halo of spontaneous undulator radiation. The bolometer is designed to determine the total energy of each laser pulse to within (1- x ) Sr x MnO 3 sensor array at the metal-insulator transition, where the composition x is adjusted to produce the desired transition temperature. We discuss design considerations and material choices, and present numerical simulations of the thermal response

  13. Design of compact dispersion interferometer with a high efficiency nonlinear crystal and a low power CO2 laser

    Science.gov (United States)

    Akiyama, T.; Yoshimura, S.; Tomita, K.; Shirai, N.; Murakami, T.; Urabe, K.

    2017-12-01

    When the electron density of a plasma generated in high pressure environment is measured by a conventional interferometer, the phase shifts due to changes of the neutral gas density cause significant measurement errors. A dispersion interferometer, which measures the phase shift that arises from dispersion of medium between the fundamental and the second harmonic wavelengths of laser light, can suppress the measured phase shift due to the variations of neutral gas density. In recent years, the CO2 laser dispersion interferometer has been applied to the atmospheric pressure plasmas and its feasibility has been demonstrated. By combining a low power laser and a high efficiency nonlinear crystal for the second harmonic component generation, a compact dispersion interferometer can be designed. The optical design and preliminary experiments are conducted.

  14. Design of Laser Welding Parameters for Joining Ti Grade 2 and AW 5754 Aluminium Alloys Using Numerical Simulation

    Directory of Open Access Journals (Sweden)

    Mária Behúlová

    2017-01-01

    Full Text Available Joining of dissimilar Al-Ti alloys is very interesting from the point of view of weight reduction of components and structures in automotive or aerospace industries. In the dependence on cooling rate and chemical composition, rapid solidification of Al-Ti alloys during laser welding can lead to the formation of metastable phases and brittle intermetallic compounds that generally reduce the quality of produced weld joints. The paper deals with design and testing of welding parameters for preparation of weld joints of two sheets with different thicknesses from titanium Grade 2 and AW 5754 aluminium alloy. Temperature fields developed during the formation of Al-Ti butt joints were investigated by numerical simulation in ANSYS software. The influence of laser welding parameters including the laser power and laser beam offset on the temperature distribution and weld joint formation was studied. The results of numerical simulation were verified by experimental temperature measurement during laser beam welding applying the TruDisk 4002 disk laser. The microstructure of produced weld joints was assessed by light microscopy and scanning electron microscopy. EDX analysis was applied to determine the change in chemical composition across weld joints. Mechanical properties of weld joints were evaluated using tensile tests and Vickers microhardness measurements.

  15. Design of a picosecond-laser-driven Ni-like Mo x-ray laser near 20 nm

    International Nuclear Information System (INIS)

    Nilsen, J.

    1997-01-01

    The gain is predicted for a solid molybdenum target illuminated by several joules of combined energy from a nanosecond laser pulse to create a preplasma followed by a picosecond laser pulse to drive the gain. Gains greater than 300cm -1 are predicted for the Ni-like Mo 4d 1 S 0 →4p 1 P 1 transition at 18.9 nm, which is driven by the monopole collisional excitation. High gain is also predicted for a self-photo-pumped 4f 1 P 1 →4d 1 P 1 transition at 22.0 nm and several other transitions driven by inner shell collisional ionization. copyright 1997 Optical Society of America

  16. The design and development of CO2 medium-level laser power calibration system for industrial and medical applications in Thailand

    Science.gov (United States)

    Nontapot, Kanokwan

    2018-03-01

    The carbon dioxide laser (CO2 laser) is one of the most useful and is the highest CW laser at the present. The laser produces infrared light at 10.6 um. Due to its high power, CO2 lasers are usually used in industrial applications such as cutting and welding, or for engraving at less power. CO2 lasers are also used widely in medical applications, such as laser surgery, skin resurfacing, and removing mold, due to water (biological tissue) absorb light at this wavelength very well. CO2 lasers are also used as LIDAR laser source for military range finding applications because of the transparency of the atmosphere to infrared light. Due to the increasing use of CO2 lasers laser in industrial and medical applications in Thailand, the National Institute of Metrology (Thailand) has set up a CO2 laser power calibration system and provide calibration service to customers this year. The service support calibration of medium-level laser power at wavelength of 10.6 um and at power range 100 mW-10W. The design and development of the calibration system will be presented.

  17. Validation and Variation of Upper Layer Thickness in South China Sea from Satellite Altimeter Data

    Directory of Open Access Journals (Sweden)

    Nan-Jung Kuo

    2008-06-01

    Full Text Available Satellite altimeter data from 1993 to 2005 has been used to analyze the seasonal variation and the interannual variability of upper layer thickness (ULT in the South China Sea (SCS. Base on in-situ measurements, the ULT is defined as the thickness from the sea surface to the depth of 16°C isotherm which is used to validate the result derived from satellite altimeter data. In comparison with altimeter and in-situ derived ULTs yields a correlation coefficient of 0.92 with a slope of 0.95 and an intercept of 6 m. The basin averaged ULT derived from altimeter is 160 m in winter and 171 m in summer which is similar to the in-situ measurements of 159 m in winter and 175 m in summer. Both results also show similar spatial patterns. It suggests that the sea surface height data derived from satellite sensors are usable for study the variation of ULT in the semi-closed SCS. Furthermore, we also use satellite derived ULT to detect the development of eddy. Interannual variability of two meso-scale cyclonic eddies and one anticyclonic eddy are strongly influenced by El Niño events. In most cases, there are highly positive correlations between ULT and sea surface temperature except the periods of El Niño. During the onset of El Niño event, ULT is deeper when sea surface temperature is lower.

  18. Detection and characterization of ship targets using CryoSat-2 altimeter waveforms

    OpenAIRE

    G?mez-Enri, Jesus; Scozzari, Andrea; Soldovieri, Francesco; Coca, Josep; Vignudelli, Stefano

    2016-01-01

    This article describes an investigation of the new possibilities offered by SAR altimetry compared with conventional altimetry in the detection and characterization of non-ocean targets. We explore the capabilities of the first SAR altimeter installed on the European Space Agency satellite CryoSat-2 for the detection and characterization of ships. We propose a methodology for the detection of anomalous targets in the radar signals, based on the advantages of SAR/Doppler processing over conven...

  19. Long-term and seasonal Caspian Sea level change from satellite gravity and altimeter measurements

    Science.gov (United States)

    Chen, J. L.; Wilson, C. R.; Tapley, B. D.; Save, H.; Cretaux, Jean-Francois

    2017-03-01

    We examine recent Caspian Sea level change by using both satellite radar altimetry and satellite gravity data. The altimetry record for 2002-2015 shows a declining level at a rate that is approximately 20 times greater than the rate of global sea level rise. Seasonal fluctuations are also much larger than in the world oceans. With a clearly defined geographic region and dominant signal magnitude, variations in the sea level and associated mass changes provide an excellent way to compare various approaches for processing satellite gravity data. An altimeter time series derived from several successive satellite missions is compared with mass measurements inferred from Gravity Recovery and Climate Experiment (GRACE) data in the form of both spherical harmonic (SH) and mass concentration (mascon) solutions. After correcting for spatial leakage in GRACE SH estimates by constrained forward modeling and accounting for steric and terrestrial water processes, GRACE and altimeter observations are in complete agreement at seasonal and longer time scales, including linear trends. This demonstrates that removal of spatial leakage error in GRACE SH estimates is both possible and critical to improving their accuracy and spatial resolution. Excellent agreement between GRACE and altimeter estimates also provides confirmation of steric Caspian Sea level change estimates. GRACE mascon estimates (both the Jet Propulsion Laboratory (JPL) coastline resolution improvement version 2 solution and the Center for Space Research (CSR) regularized) are also affected by leakage error. After leakage corrections, both JPL and CSR mascon solutions also agree well with altimeter observations. However, accurate quantification of leakage bias in GRACE mascon solutions is a more challenging problem.

  20. Conceptual design of a bright electron injector based on a laser-driven photocathode rf electron gun

    International Nuclear Information System (INIS)

    Chattopadhyay, S.; Chen, Y.J.; Hopkins, D.; Kim, K.J.; Kung, A.; Miller, R.; Sessler, A.; Young, T.

    1988-09-01

    Conceptual design of a bright electron injector for the 1 GeV high gradient test experiment, envisaged by the LLNL-SLAC-LBL collaboration on the Relativistic Klystron is presented. The design utilizes a high-brightness laser-driven rf photocathode electron gun, similar to the pioneering LANL early studies in concept (different parametrically however), together with achromatic magnetic bunching and transport systems and diagnostics. The design is performed with attention to possible use in an FEL as well. A simple but realistic analytic model including longitudinal and transverse space-charge and rf effects and extensive computer simulation form the basis of the parametric choice for the source. These parameters are used as guides for the design of the picosecond laser system and magnetic bunching section. 4 refs., 5 figs., 2 tabs

  1. Requirements and design of a high stable infrared free electron laser at LBL

    International Nuclear Information System (INIS)

    Kim, K.J.; Berz, M.; Chattopadhyay, S.; Gough, R.; Kim, C.; Kung, A.H.; Xie, M.; Edighoffer, J.; Stein, W.

    1990-06-01

    An infrared free electron laser (IRFEL) is being designed for the Chemical Dynamics Research Laboratory (CDRL) at LBL. The FEL is based on a 50 MeV RF linac operating in synchronization to the Advanced Light Source (ALS), and will produce intense (100 μJ per micropulse), narrow bandwidth (narrower than 0.1%) radiation between 3 μ and 50 μ. In the design, we pay particular attention to the FEL stability issues and require that the fluctuations in electron beam energy and in timing be less than 0.05% and 0.1 ps, respectively. The FEL spectrum can then be stabilized to about 10 -3 , or if grating is used, to 10 -4 . We discuss various sources of fluctuations in the gun, the bunchers and the accelerator sections, as well as the feedback and feedforward schemes to reduce these fluctuations. The accelerator structure is chosen to be of the side coupled, standing wave type for easier control. The beam transport is made isochronous to avoid the coupling between the energy and the timing fluctuations. 9 refs., 2 figs

  2. Theory and design of a harmonic Ubitron/Free-Electron laser

    International Nuclear Information System (INIS)

    Freund, H.P.; Bluem, H.

    1989-01-01

    A fully three-dimensional nonlinear analysis of the harmonic Ubitrono/Free-Election laser is discussed which is valid for arbitrary harmonic number. The analysis has been performed for a configuration consisting of a beam propagating through a loss-free rectangular waveguide in the presence of a planar wiggler field. The wiggler model includes an adiabatic entry taper to model the injection of the beam into the wiggler, parabolic pole pieces to provide additional focussing in the plane normal to the wiggler, and an amplitude taper downstream from the entry region for efficiency enhancement. The advantage of harmonic operation is that relatively high operating frequencies may be obtained with relatively modest beam energies; however, this occurs at the expense of a greater sensitivity to beam thermal effects. In addition to enhancing the extraction efficiency, a tapered wiggler has been shown to reduce the sensitivity of the interaction to thermal effects. Thus, the tapered wiggler is designed to counter the increased thermal sensitivity of the harmonic interaction. Suppression of the fundamental is accomplished by the careful choice of the beam energy, waveguide radius, and wiggler period in order to ensure that no resonance is possible at the fundamental. Specific design criteria for a third harmonic experiment operating at 15 GHz with a 55 keV electron beam are discussed

  3. Design of microreactor by integration of reverse engineering and direct metal laser sintering process

    Energy Technology Data Exchange (ETDEWEB)

    Bineli, Aulus Roberto Romao; Gimenez Perez, Ana Paula; Bernardes, Luiz Fernando; Munhoz, Andre Luiz Jardini; Maciel Filho, Rubens [Universidade de Campinas (LOPCA/UNICAMP), SP (Brazil). School of Chemical Engineering. Laboratory of Optimization, Design and Advanced Process Control], Email: aulus@feq.unicamp.br

    2010-07-01

    The propose of this work is to present high precision microfabrication facilities using computer aided technologies as Reverse Engineering (RE) and Rapid Manufacturing (RM) to analyze, design and construct micro reactors to produce high content hydrogen gas. Micro reactors are very compact, have a high surface to volume ratio, exhibit enhanced heat and mass transfer rates, denotes extremely low pressure drop and allow improved thermal integration in the processes involved. The main goals of micro reactors are the optimization of conventional chemical plants and low footprint, opening different ways to research new process technologies and synthesis of new products. In this work, a microchannels plate and housing structure of these plates were fabricated using DMLS method (Direct Metal Laser Sintering). The plates were analyzed to verify the minimum thickness wall that machine can produce, and the housing structure were digitalized, using a 3D scanning, to perform a 3D inspection and to verify the deflection of the constructed part in comparison with original CAD design models. It was observed that DMLS systems are able to produce micro reactors and microchannels plates with high precision at different metallic materials. However, it is important to choose appropriate conditions to avoid residual stresses and consequently warping parts. (author)

  4. Engineering design of the interaction waveguide for high-power accelerator-driven microwave free-electron lasers

    International Nuclear Information System (INIS)

    Hopkins, D.B.; Clay, H.W.; Stallard, B.W.; Throop, A.L.; Listvinsky, G.; Makowski, M.A.

    1989-01-01

    Linear induction accelerators (LIAs) operating at beam energies of a few million electron volts and currents of a few thousand amperes are suitable drivers for free-electron lasers (FELs). Such lasers are capable of producing gigawatts of peak power and megawatts of average power at microwave frequencies. Such devices are being studied as possible power sources for future high-gradient accelerators and are being constructed for plasma heating applications. At high power levels, the engineering design of the interaction waveguide presents a challenge. This paper discusses several concerns, including electrical breakdown and metal fatigue limits, choice of material, and choice of operating propagation mode. 13 refs., 3 figs

  5. Design optimization of single-main-amplifier KrF laser-fusion systems

    International Nuclear Information System (INIS)

    Harris, D.B.; Pendergrass, J.H.

    1985-01-01

    KrF lasers appear to be a very promising laser fusion driver for commercial applications. The Large Amplifier Module for the Aurora Laser System at Los Alamos is the largest KrF laser in the world and is currently operating at 5 kJ with 10 to 15 kJ eventually expected. The next generation system is anticipated to be a single-main-amplifier system that generates approximately 100 kJ. This paper examines the cost and efficiency tradeoffs for a complete single-main-amplifier KrF laser fusion experimental facility. It has been found that a 7% efficient $310/joule complete laser-fusion system is possible by using large amplifier modules and high optical fluences

  6. Design of a high-power, high-brightness Nd:YAG solar laser.

    Science.gov (United States)

    Liang, Dawei; Almeida, Joana; Garcia, Dário

    2014-03-20

    A simple high-power, high-brightness Nd:YAG solar laser pumping approach is presented in this paper. The incoming solar radiation is both collected and concentrated by four Fresnel lenses and redirected toward a Nd:YAG laser head by four plane-folding mirrors. A fused-silica secondary concentrator is used to compress the highly concentrated solar radiation to a laser rod. Optimum pumping conditions and laser resonator parameters are found through ZEMAX and LASCAD numerical analysis. Solar laser power of 96 W is numerically calculated, corresponding to the collection efficiency of 24  W/m². A record-high solar laser beam brightness figure of merit of 9.6 W is numerically achieved.

  7. Design and Fabrication of a Precision Template for Spine Surgery Using Selective Laser Melting (SLM

    Directory of Open Access Journals (Sweden)

    Di Wang

    2016-07-01

    Full Text Available In order to meet the clinical requirements of spine surgery, this paper proposes the fabrication of the customized template for spine surgery through computer-aided design. A 3D metal printing-selective laser melting (SLM technique was employed to directly fabricate the 316L stainless steel template, and the metal template with tiny locating holes was used as an auxiliary tool to insert spinal screws inside the patient’s body. To guarantee accurate fabrication of the template for cervical vertebra operation, the contact face was placed upwards to improve the joint quality between the template and the cervical vertebra. The joint surface of the printed template had a roughness of Ra = 13 ± 2 μm. After abrasive blasting, the surface roughness was Ra = 7 ± 0.5 μm. The surgical metal template was bound with the 3D-printed Acrylonitrile Butadiene Styrene (ABS plastic model. The micro-hardness values determined at the cross-sections of SLM-processed samples varied from HV0.3 250 to HV0.3 280, and the measured tensile strength was in the range of 450 MPa to 560 MPa, which showed that the template had requisite strength. Finally, the metal template was clinically used in the patient’s surgical operation, and the screws were inserted precisely as the result of using the auxiliary template. The geometrical parameters of the template hole (e.g., diameter and wall thickness were optimized, and measures were taken to optimize the key geometrical units (e.g., hole units in metal 3D printing. Compared to the traditional technology of screw insertion, the use of the surgical metal template enabled the screws to be inserted more easily and accurately during spinal surgery. However, the design of the high-quality template should fully take into account the clinical demands of surgeons, as well as the advice of the designing engineers and operating technicians.

  8. Design and Fabrication of a Precision Template for Spine Surgery Using Selective Laser Melting (SLM).

    Science.gov (United States)

    Wang, Di; Wang, Yimeng; Wang, Jianhua; Song, Changhui; Yang, Yongqiang; Zhang, Zimian; Lin, Hui; Zhen, Yongqiang; Liao, Suixiang

    2016-07-22

    In order to meet the clinical requirements of spine surgery, this paper proposes the fabrication of the customized template for spine surgery through computer-aided design. A 3D metal printing-selective laser melting (SLM) technique was employed to directly fabricate the 316L stainless steel template, and the metal template with tiny locating holes was used as an auxiliary tool to insert spinal screws inside the patient's body. To guarantee accurate fabrication of the template for cervical vertebra operation, the contact face was placed upwards to improve the joint quality between the template and the cervical vertebra. The joint surface of the printed template had a roughness of Ra = 13 ± 2 μm. After abrasive blasting, the surface roughness was Ra = 7 ± 0.5 μm. The surgical metal template was bound with the 3D-printed Acrylonitrile Butadiene Styrene (ABS) plastic model. The micro-hardness values determined at the cross-sections of SLM-processed samples varied from HV0.3 250 to HV0.3 280, and the measured tensile strength was in the range of 450 MPa to 560 MPa, which showed that the template had requisite strength. Finally, the metal template was clinically used in the patient's surgical operation, and the screws were inserted precisely as the result of using the auxiliary template. The geometrical parameters of the template hole (e.g., diameter and wall thickness) were optimized, and measures were taken to optimize the key geometrical units (e.g., hole units) in metal 3D printing. Compared to the traditional technology of screw insertion, the use of the surgical metal template enabled the screws to be inserted more easily and accurately during spinal surgery. However, the design of the high-quality template should fully take into account the clinical demands of surgeons, as well as the advice of the designing engineers and operating technicians.

  9. The effect of optical system design for laser micro-hole drilling process

    Science.gov (United States)

    Ding, Chien-Fang; Lan, Yin-Te; Chien, Yu-Lun; Young, Hong-Tsu

    2017-08-01

    Lasers are a promising high accuracy tool to make small holes in composite or hard material. They offer advantages over the conventional machining process, which is time consuming and has scaling limitations. However, the major downfall in laser material processing is the relatively large heat affect zone or number of molten burrs it generates, even when using nanosecond lasers over high-cost ultrafast lasers. In this paper, we constructed a nanosecond laser processing system with a 532 nm wavelength laser source. In order to enhance precision and minimize the effect of heat generation with the laser drilling process, we investigated the geometric shape of optical elements and analyzed the images using the modulation transfer function (MTF) and encircled energy (EE) by using optical software Zemax. We discuss commercial spherical lenses, including plano-convex lenses, bi-convex lenses, plano-concave lenses, bi-concave lenses, best-form lenses, and meniscus lenses. Furthermore, we determined the best lens configuration by image evaluation, and then verified the results experimentally by carrying out the laser drilling process on multilayer flexible copper clad laminate (FCCL). The paper presents the drilling results obtained with different lens configurations and found the best configuration had a small heat affect zone and a clean edge along laser-drilled holes.

  10. Quasi-CW Laser Diode Bar Life Tests

    Science.gov (United States)

    Stephen, Mark A.; Krainak, Michael A.; Dallas, Joseph L.

    1997-01-01

    NASA's Goddard Space Flight Center is developing technology for satellite-based, high peak power, LIDAR transmitters requiring 3-5 years of reliable operation. Semi-conductor laser diodes provide high efficiency pumping of solid state lasers with the promise of long-lived, reliable operation. 100-watt quasi- CW laser diode bars have been baselined for the next generation laser altimeters. Multi-billion shot lifetimes are required. The authors have monitored the performance of several diodes for billions of shots and investigated operational modes for improving diode lifetime.

  11. Study and characterization of ceramic materials from natural origin for application in jewellery design using laser texturing as innovation

    International Nuclear Information System (INIS)

    Elesbao, T.R.; Carus, L.A.; Tabarelli, A.C.; Vieira, R.P.; Takimi, A.S.

    2012-01-01

    Technological development has been largely responsible for changes in the jewelry market. Seeking to contribute to the development of new products, this study analyzed the technique of laser texturing, aiming to add commercial and aesthetic values to the mother of pearl, material used in the jewelry field. The methodology was divided into physico-chemical characterization of the mother-of-pearl and of the resulting residue of laser texturing and analysis of the interaction of laser with the surface of the mother-of-pearl. The characterizations carried out were: Infrared spectroscopy, X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. Results indicate that the studied material is composed mainly by the aragonite crystal phase, different from that resulting residue from texturing process. Although the process remove some of the gem material, the effect water characteristic of the mother-of-pearl is maintained, suggesting that technology combined with research and design can increase the value of this material. (author)

  12. Conceptual design of a large E-beam-pumped KrF laser for ICF commercial applications

    International Nuclear Information System (INIS)

    Harris, D.B.; Waganer, L.M.; Zuckerman, D.S.; Bowers, D.A.

    1986-01-01

    Two types of KrF lasers appear attractive as a driver for an ICF electric power plant. The original concept uses large electron-beam-pumped amplifiers and pure angular multiplexing to deliver short, shaped pulses to the target. A recently conceived alternate concept uses many small, long-pulse e-beam sustained discharge lasers which transfer their energy through the forward Raman process to a multiplexed set of beams to deliver the energy to target. Preliminary comparisons of the two systems indicate that the original concept has both a lower cost and a lower system efficiency, and both concepts appear to be nearly equally attractive as an ICF driver for an electric power plant. This paper examines a 4.8 MJ, 5 Hz KrF laser system designed using the original concept. The laser uses 24 main amplifiers arranged in eight sets of three amplifiers each. This layout optimizes both the optical system and the gas flow system, and uses a simple target illumination scheme that provides neutron shielding to allow hands-on maintenance in the laser hall

  13. In gas laser ionization and spectroscopy experiments at the Superconducting Separator Spectrometer (S3): Conceptual studies and preliminary design

    International Nuclear Information System (INIS)

    Ferrer, R.; Bastin, B.; Boilley, D.; Creemers, P.; Delahaye, P.; Liénard, E.; Fléchard, X.; Franchoo, S.; Ghys, L.; Huyse, M.; Kudryavtsev, Yu.; Lecesne, N.; Lu, H.; Lutton, F.; Mogilevskiy, E.; Pauwels, D.; Piot, J.; Radulov, D.; Rens, L.; Savajols, H.

    2013-01-01

    Highlights: • A setup to perform In-Gas Laser Ionization and Spectroscopy experiments at the Super Separator Spectrometer is presented. • The reported studies address important aspects necessary to applied the IGLIS technique to short-lived isotopes. • An R and D phase required to reach an enhanced spectral resolution will be carried out at KU Leuven. • High-sensitivity and enhanced-resolution laser spectroscopy studies will be possible with the IGLIS setup at S 3 . -- Abstract: The results of preparatory experiments and the preliminary designs of a new in-gas laser ionization and spectroscopy setup, to be coupled to the Super Separator Spectrometer S 3 of SPIRAL2-GANIL, are reported. Special attention is given to the development and tests to carry out a full implementation of the in-gas jet laser spectroscopy technique. Application of this novel technique to radioactive species will allow high-sensitivity and enhanced-resolution laser spectroscopy studies of ground- and excited-state properties of exotic nuclei

  14. Design, implementation and testing of a fuzzy control scheme for laser welding

    NARCIS (Netherlands)

    Jauregui Becker, Juan Manuel; Aalderink, B.J.; Aalderink, Benno; Aarts, Ronald G.K.M.; Olde Benneker, Jeroen; Meijer, J.

    2008-01-01

    A fuzzy logic controller (FLC) scheme has been developed for laser welding. Process light emissions are measured and combined to determine the current status of the welding process. If the process is not in a desired welding state, the FLC will adapt the laser power. The FLC has been demonstrated

  15. Design of a Compact, Bimorph Deformable Mirror-Based Adaptive Optics Scanning Laser Ophthalmoscope.

    Science.gov (United States)

    He, Yi; Deng, Guohua; Wei, Ling; Li, Xiqi; Yang, Jinsheng; Shi, Guohua; Zhang, Yudong

    2016-01-01

    We have designed, constructed and tested an adaptive optics scanning laser ophthalmoscope (AOSLO) using a bimorph mirror. The simulated AOSLO system achieves diffraction-limited criterion through all the raster scanning fields (6.4 mm pupil, 3° × 3° on pupil). The bimorph mirror-based AOSLO corrected ocular aberrations in model eyes to less than 0.1 μm RMS wavefront error with a closed-loop bandwidth of a few Hz. Facilitated with a bimorph mirror at a stroke of ±15 μm with 35 elements and an aperture of 20 mm, the new AOSLO system has a size only half that of the first-generation AOSLO system. The significant increase in stroke allows for large ocular aberrations such as defocus in the range of ±600° and astigmatism in the range of ±200°, thereby fully exploiting the AO correcting capabilities for diseased human eyes in the future.

  16. Design of collimating and rearrangement systems of laser diode array beam

    Science.gov (United States)

    Gao, Runmei; Fang, Tao; Fu, Rulian; Yao, Jianquan

    2015-10-01

    To improve the laser diode output beam quality, micro-cylindrical lens and the step-type lens combination are designed. The former is used to collimate beam in fast-axis direction, while the latter plays a role in the slow-axis of splitting and the rearrangement. The micro-column semi-elliptical lens is made with the drops of spherical zoom lensin electric field and with the help of the material properties of light-cured production, which can reduce the reflection of the front surface and total reflection loss of the after. The divergence angle in the fast axis is compressed to roughly the same as that in the slow-axis direction; Stepped lens splits compressed long strip beam in the slow axis, with parallelogram style of level equidistant and rearrange in the fast axis direction. The spot in the slow axis gets smaller and the spot becomes larger in the fast axis. At last divergence angle and the beam spot achieve balanced in the fast axis and slow axis, optical parameters BPP integrates approximate the same, and beam quality can be improved.

  17. [Design and fabrication of the custom-made titanium condyle by selective laser melting technology].

    Science.gov (United States)

    Chen, Jianyu; Luo, Chongdai; Zhang, Chunyu; Zhang, Gong; Qiu, Weiqian; Zhang, Zhiguang

    2014-10-01

    To design and fabricate the custom-made titanium mandibular condyle by the reverse engineering technology combined with selective laser melting (SLM) technology and to explore the mechanical properties of the SLM-processed samples and the application of the custom-made condyle in the temporomandibular joint (TMJ) reconstruction. The three-dimensional model of the mandibular condyle was obtained from a series of CT databases. The custom-made condyle model was designed by the reverse engineering software. The mandibular condyle was made of titanium powder with a particle size of 20-65 µm as the basic material and the processing was carried out in an argon atmosphere by the SLM machine. The yield strength, ultimate strength, bending strength, hardness, surface morphology and roughness were tested and analyzed. The finite element analysis (FEA) was used to analyze the stress distribution. The complex geometry and the surface of the custom-made condyle can be reproduced precisely by the SLM. The mechanical results showed that the yield strength, ultimate strength, bending strength and hardness were (559±14) MPa, (659±32) MPa, (1 067±42) MPa, and (212±4)HV, respectively. The surface roughness was reduced by sandblast treatment. The custom-made titanium condyle can be fabricated by SLM technology which is time-saving and highly digitized. The mechanical properties of the SLM sample can meet the requirements of surgical implant material in the clinic. The possibility of fabricating custom-made titanium mandibular condyle combined with the FEA opens new interesting perspectives for TMJ reconstruction.

  18. Design and construction of a 76m long-travel laser enclosure for a space occulter testbed

    Science.gov (United States)

    Galvin, Michael; Kim, Yunjong; Kasdin, N. Jeremy; Sirbu, Dan; Vanderbei, Robert; Echeverri, Dan; Sagolla, Giuseppe; Rousing, Andreas; Balasubramanian, Kunjithapatham; Ryan, Daniel; Shaklan, Stuart; Lisman, Doug

    2016-07-01

    Princeton University is upgrading our space occulter testbed. In particular, we are lengthening it to 76m to achieve flightlike Fresnel numbers. This much longer testbed required an all-new enclosure design. In this design, we prioritized modularity and the use of commercial off-the-shelf (COTS) and semi-COTS components. Several of the technical challenges encountered included an unexpected slow beam drift and black paint selection. Herein we describe the design and construction of this long-travel laser enclosure.

  19. Analysis and Validation of ZY-3 02 Satellite Laser Altimetry Data

    Directory of Open Access Journals (Sweden)

    LI Guoyuan

    2017-12-01

    Full Text Available ZY-3 02 satellite loaded with Chinese first earth observing satellite laser altimeter,and has been launched successfully on 30th May,2016. In this paper,the theoretical accuracy of the laser altimeter is analyzed,and several experimental areas are used to verify the actual accuracy. At the same time,the application of the laser altimetry data in the field of space-borne photogrammetry is tested. The laser altimetry theoretical accuracy of ZY-3 02 satellite in the flat area (slope less than 2 degrees is about 0.85 m and 14.2 m in the elevation and planimetry direction,respectively. The effective laser altimetry data account for about 23.89%,and near the calibration field the elevation accuracy is 0.89 m,and planimetry accuracy is about 14.76 m. Moreover,the verified elevation accuracy is 1.09 m in the North China by high precision DSM terrain data,and laser footprint points accuracy on the surface of the Bohai inland sea is about 0.47 m. When the laser foot print point is used as elevation control point,the elevation accuracy of the ZY-3 02 satellite stereo images in Shaanxi Weinan can be increased from 11.54 m to 1.90 m without GCPs. Although ZY3-02 satellite laser altimeter is just a test,the results proved that the domestic satellite laser altimetry data can effectively improve the stereo images without GCPs,which will be valuable in the global mapping project. It is suggest that operational laser altimeter equip on the next satellite of ZY-3 serials.

  20. WavePropaGator: interactive framework for X-ray free-electron laser optics design and simulations1

    OpenAIRE

    Samoylova, Liubov; Buzmakov, Alexey; Chubar, Oleg; Sinn, Harald

    2016-01-01

    This article describes the WavePropaGator (WPG) package, a new interactive software framework for coherent and partially coherent X-ray wavefront propagation simulations. The package has been developed at European XFEL for users at the existing and emerging free-electron laser (FEL) facilities, as well as at the third-generation synchrotron sources and future diffraction-limited storage rings. The WPG addresses the needs of beamline scientists and user groups to facilitate the design, optimiz...

  1. Determination of ocean tides from the first year of TOPEX/POSEIDON altimeter measurements

    Science.gov (United States)

    Ma, X. C.; Shum, C. K.; Eanes, R. J.; Tapley, B. D.

    1994-01-01

    An improved geocentric global ocean tide model has been determined using 1 year of TOPEX/POSEIDON altimeter measurements to provide corrections to the Cartwright and Ray (1991) model (CR91). The corrections were determined on a 3 deg x 3 deg grid using both the harmonic analysis method and the response method. The two approaches produce similar solutions. The effect on the tide solution of simultaneously adjusting radial orbit correction parameters using altimeter measurements was examined. Four semidiurnal (N(sub 2), M(sub 2), S(sub 2) and K(sub 2)), four diurnal (Q(sdub 1), O(sub 1), P(sub 1), and K(sub 1)), and three long-period (S(sub sa), M(sub m), and M(sub f)) constituents, along with the variations at the annual frequency, were included in the harmomnic analysis solution. The observed annual variations represents the first global measurement describing accurate seasonal changes of the ocean during an El Nino year. The corrections to the M(sub 2) constituent have an root mean square (RMS) of 3.6 cm and display a clear banding pattern with regional highs and lows reaching 8 cm. The improved tide model reduces the weighted altimeter crossover residual from 9.8 cm RMS, when the CR91 tide model is used, to 8.2 cm on RMS. Comparison of the improved model to pelagic tidal constants determined from 80 tide gauges gives RMS differences of 2.7 cm for M(sub 2) and 1.7 cm for K(sub 1). Comparable values when the CR91 model is used are 3.9 cm and 2.0 cm, respectively. Examination of TOPEX/POSEIDON sea level anomaly variations using the new tide model further confirms that the tide model has been improved.

  2. Design and Performance of a Focus-Detection System for Use in Laser Micromachining

    Directory of Open Access Journals (Sweden)

    Binh Xuan Cao

    2016-01-01

    Full Text Available We describe a new approach for locating the focal position in laser micromachining. This approach is based on a feedback system that uses a charge-coupled device (CCD camera, a beam splitter, and a mirror to focus a laser beam on the surface of a work piece. We tested the proposed method for locating the focal position by using Zemax simulations, as well as physically carrying out drilling processes. Compared with conventional methods, this approach is advantageous because: the implementation is simple, the specimen can easily be positioned at the focal position, and the dynamically adjustable scan amplitude and the CCD camera can be used to monitor the laser beam’s profile. The proposed technique will be particularly useful for locating the focal position on any surface in laser micromachining.

  3. Conceptual design of 100 J cryogenically-cooled multi-slab laser for fusion research

    Directory of Open Access Journals (Sweden)

    Divoky M.

    2013-11-01

    Full Text Available We present a comparison of two alternative laser layouts for HiLASE and ELI Beamlines projects. The cryogenically cooled laser is 100 J class with 2 ns pulse length and operates at 10 Hz repetition rate. The laser beam is intended for industrial applications in HiLASE, for OPCPA pumping in ELI Beamlines and can serve as a test bed for large scale high repetition rate fusion lasers. First layout utilizes classical scheme with preamplifier and main amplifier, while the second layout utilizes single amplifier scheme with two amplifier heads. The comparison is based on the results obtained from homemade MATLAB code for evaluation of amplified spontaneous emission and stored energy and on a beam propagation simulated in MIRÓ code.

  4. Transverse-flow quasi-cw HF chemical laser: design and preliminary performance

    International Nuclear Information System (INIS)

    Gagne, J.M.; Mah, S.Q.; Conturie, Y.

    1974-01-01

    A small transverse-flow HF chemical laser has been constructed using a large volume microwave plasma generator for the production of F atoms. The F atoms react with hydrogen to form the lasing HF molecules. The active medium is about 5 cm long, and the maximum average laser power was found to be 560 mW for all lines. Three laser lines with wavelengths 2.61 μm, 2.64 μm, and 2.73 μm were observed. The time-varying laser transition profile closely resembles the density profile of the excited fluorine atoms in the plasma. Both profiles are greatly affected by changes in flow conditions

  5. Laser fusion: an overview

    International Nuclear Information System (INIS)

    Boyer, K.

    1975-01-01

    The laser fusion concept is described along with developments in neodymium and carbon dioxide lasers. Fuel design and fabrication are reviewed. Some spin-offs of the laser fusion program are discussed. (U.S.)

  6. An improved and homogeneous altimeter sea level record from the ESA Climate Change Initiative

    DEFF Research Database (Denmark)

    Legeais, Jean-Francois; Ablain, Michael; Zawadzki, Lionel

    2018-01-01

    , the sea level ECV has been measured from space by different altimetry missions that have provided global and regional observations of sea level variations. As part of the Climate Change Initiative (CCI) program of the European Space Agency (ESA) (established in 2010), the Sea Level project (SL_cci) aimed...... to provide an accurate and homogeneous long-term satellite-based sea level record. At the end of the first phase of the project (2010-2013), an initial version (v1.1) of the sea level ECV was made available to users (Ablain et al., 2015). During the second phase of the project (2014-2017), improved altimeter...

  7. An improved and homogeneous altimeter sea level record from the ESA Climate Change Initiative

    Science.gov (United States)

    Legeais, Jean-François; Ablain, Michaël; Zawadzki, Lionel; Zuo, Hao; Johannessen, Johnny A.; Scharffenberg, Martin G.; Fenoglio-Marc, Luciana; Joana Fernandes, M.; Baltazar Andersen, Ole; Rudenko, Sergei; Cipollini, Paolo; Quartly, Graham D.; Passaro, Marcello; Cazenave, Anny; Benveniste, Jérôme

    2018-02-01

    Sea level is a very sensitive index of climate change since it integrates the impacts of ocean warming and ice mass loss from glaciers and the ice sheets. Sea level has been listed as an essential climate variable (ECV) by the Global Climate Observing System (GCOS). During the past 25 years, the sea level ECV has been measured from space by different altimetry missions that have provided global and regional observations of sea level variations. As part of the Climate Change Initiative (CCI) program of the European Space Agency (ESA) (established in 2010), the Sea Level project (SL_cci) aimed to provide an accurate and homogeneous long-term satellite-based sea level record. At the end of the first phase of the project (2010-2013), an initial version (v1.1) of the sea level ECV was made available to users (Ablain et al., 2015). During the second phase of the project (2014-2017), improved altimeter standards were selected to produce new sea level products (called SL_cci v2.0) based on nine altimeter missions for the period 1993-2015 (https://doi.org/10.5270/esa-sea_level_cci-1993_2015-v_2.0-201612; Legeais and the ESA SL_cci team, 2016c). Corresponding orbit solutions, geophysical corrections and altimeter standards used in this v2.0 dataset are described in detail in Quartly et al. (2017). The present paper focuses on the description of the SL_cci v2.0 ECV and associated uncertainty and discusses how it has been validated. Various approaches have been used for the quality assessment such as internal validation, comparisons with sea level records from other groups and with in situ measurements, sea level budget closure analyses and comparisons with model outputs. Compared with the previous version of the sea level ECV, we show that use of improved geophysical corrections, careful bias reduction between missions and inclusion of new altimeter missions lead to improved sea level products with reduced uncertainties on different spatial and temporal scales. However, there

  8. Design of high-brightness TEM00-mode solar-pumped laser for renewable material processing

    Science.gov (United States)

    Liang, D.; Almeida, J.

    2014-08-01

    The conversion of sunlight into laser light by direct solar pumping is of ever-increasing importance because broadband, temporally constant, sunlight is converted into laser light, which can be a source of narrowband, collimated, rapidly pulsed, radiation with the possibility of obtaining extremely high brightness and intensity. Nonlinear processes, such as harmonic generation, might be used to obtain broad wavelength coverage, including the ultraviolet wavelengths, where the solar flux is very weak. The direct excitation of large lasers by sunlight offers the prospect of a drastic reduction in the cost of coherent optical radiation for high average power materials processing. This renewable laser has a large potential for many applications such as high-temperature materials processing, renewable magnesium-hydrogen energy cycle and so on. We propose here a scalable TEM00 mode solar laser pumping scheme, which is composed of four firststage 1.13 m diameter Fresnel lenses with its respective folding mirrors mounted on a two-axis automatic solar tracker. Concentrated solar power at the four focal spots of these Fresnel lenses are focused individually along a common 3.5 mm diameter, 70 mm length Nd:YAG rod via four pairs of second-stage fused-silica spherical lenses and third-stage 2D-CPCs (Compound Parabolic Concentrator), sitting just above the laser rod which is also double-pass pumped by four V-shaped pumping cavities. Distilled water cools both the rod and the concentrators. 15.4 W TEM00 solar laser power is numerically calculated, corresponding to 6.7 times enhancement in laser beam brightness.

  9. Optimization and design of a laser-cutting machine using delta robot

    OpenAIRE

    Moharana, B.; Gupta, Rakesh; Kushwaha, Bashishth Kumar

    2014-01-01

    Industrial high speed laser operations the use of delta parallel robots potentially offers many benefits due to their structural stiffness and limited moving masses. This paper deals with a particular Delta, developed for high speed laser cutting. Parallel delta robot has numerous advantages in comparison with serial robots Higher stiffness and connected with that a lower mass of links the possibility of transporting heavier loads, and higher accuracy. The main drawback is however a smaller w...

  10. 1982 laser program annual report

    International Nuclear Information System (INIS)

    Hendricks, C.D.; Grow, G.R.

    1983-08-01

    This annual report covers the following eight sections: (1) laser program review, (2) laser systems and operation, (3) target design, (4) target fabrication, (5) fusion experiments program, (6) Zeus laser project, (7) laser research and development, and (8) energy applications

  11. Design of the prototype of a beam transport line for handling and selection of low energy laser-driven beams

    Energy Technology Data Exchange (ETDEWEB)

    Schillaci, F., E-mail: francesco.schillaci@eli-beams.eu [INFN-LNS, Catania (Italy); Maggiore, M. [INFN-LNL, Legnaro (Italy); Cirrone, G.A.P.; Cuttone, G.; Pisciotta, P.; Costa, M.; Rifuggiato, D.; Romano, F. [INFN-LNS, Catania (Italy); Scuderi, V. [INFN-LNS, Catania (Italy); Institute of Physics of the ASCR, ELI-Beamlines Project, Prague (Czech Republic)

    2016-11-21

    A first prototype of transport beam-line for laser-driven ion beams to be used for the handling of particles accelerated by high-power laser interacting with solid targets has been realized at INFN. The goal is the production of a controlled and stable beam in terms of energy and angular spread. The beam-line consists of two elements: an Energy Selection System (ESS), already realized and characterized with both conventional and laser-accelerated beams, and a Permanent Magnet Quadrupole system (PMQ) designed, in collaboration with SIGMAPHI (Fr), to improve the ESS performances. In this work a description of the ESS system and some results of its characterization with conventional beams are reported, in order to provide a complete explanation of the acceptance calculation. Then, the matching with the PMQ system is presented and, finally, the results of preliminary simulations with a realistic laser-driven energy spectrum are discussed demonstrating the possibility to provide a good quality beam downstream the systems.

  12. Experimental design approach to the process parameter optimization for laser welding of martensitic stainless steels in a constrained overlap configuration

    Science.gov (United States)

    Khan, M. M. A.; Romoli, L.; Fiaschi, M.; Dini, G.; Sarri, F.

    2011-02-01

    This paper presents an experimental design approach to process parameter optimization for the laser welding of martensitic AISI 416 and AISI 440FSe stainless steels in a constrained overlap configuration in which outer shell was 0.55 mm thick. To determine the optimal laser-welding parameters, a set of mathematical models were developed relating welding parameters to each of the weld characteristics. These were validated both statistically and experimentally. The quality criteria set for the weld to determine optimal parameters were the minimization of weld width and the maximization of weld penetration depth, resistance length and shearing force. Laser power and welding speed in the range 855-930 W and 4.50-4.65 m/min, respectively, with a fiber diameter of 300 μm were identified as the optimal set of process parameters. However, the laser power and welding speed can be reduced to 800-840 W and increased to 4.75-5.37 m/min, respectively, to obtain stronger and better welds.

  13. A simulation environment for assisting system design of coherent laser doppler wind sensor for active wind turbine pitch control

    Science.gov (United States)

    Shinohara, Leilei; Pham Tran, Tuan Anh; Beuth, Thorsten; Umesh Babu, Harsha; Heussner, Nico; Bogatscher, Siegwart; Danilova, Svetlana; Stork, Wilhelm

    2013-05-01

    In order to assist a system design of laser coherent Doppler wind sensor for active pitch control of wind turbine systems (WTS), we developed a numerical simulation environment for modeling and simulation of the sensor system. In this paper we present this simulation concept. In previous works, we have shown the general idea and the possibility of using a low cost coherent laser Doppler wind sensing system for an active pitch control of WTS in order to achieve a reduced mechanical stress, increase the WTS lifetime and therefore reduce the electricity price from wind energy. Such a system is based on a 1.55μm Continuous-Wave (CW) laser plus an erbium-doped fiber amplifier (EDFA) with an output power of 1W. Within this system, an optical coherent detection method is chosen for the Doppler frequency measurement in megahertz range. A comparatively low cost short coherent length laser with a fiber delay line is used for achieving a multiple range measurement. In this paper, we show the current results on the improvement of our simulation by applying a Monte Carlo random generation method for positioning the random particles in atmosphere and extend the simulation to the entire beam penetrated space by introducing a cylindrical co-ordinate concept and meshing the entire volume into small elements in order to achieve a faster calculation and gain more realistic simulation result. In addition, by applying different atmospheric parameters, such as particle sizes and distributions, we can simulate different weather and wind situations.

  14. Laser Intertial Fusion Energy: Neutronic Design Aspects of a Hybrid Fusion-Fission Nuclear Energy System

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Kevin James [Univ. of California, Berkeley, CA (United States)

    2010-04-08

    This study investigates the neutronics design aspects of a hybrid fusion-fission energy system called the Laser Fusion-Fission Hybrid (LFFH). A LFFH combines current Laser Inertial Confinement fusion technology with that of advanced fission reactor technology to produce a system that eliminates many of the negative aspects of pure fusion or pure fission systems. When examining the LFFH energy mission, a significant portion of the United States and world energy production could be supplied by LFFH plants. The LFFH engine described utilizes a central fusion chamber surrounded by multiple layers of multiplying and moderating media. These layers, or blankets, include coolant plenums, a beryllium (Be) multiplier layer, a fertile fission blanket and a graphite-pebble reflector. Each layer is separated by perforated oxide dispersion strengthened (ODS) ferritic steel walls. The central fusion chamber is surrounded by an ODS ferritic steel first wall. The first wall is coated with 250-500 μm of tungsten to mitigate x-ray damage. The first wall is cooled by Li17Pb83 eutectic, chosen for its neutron multiplication and good heat transfer properties. The Li17Pb83 flows in a jacket around the first wall to an extraction plenum. The main coolant injection plenum is immediately behind the Li17Pb83, separated from the Li17Pb83 by a solid ODS wall. This main system coolant is the molten salt flibe (2LiF-BeF2), chosen for beneficial neutronics and heat transfer properties. The use of flibe enables both fusion fuel production (tritium) and neutron moderation and multiplication for the fission blanket. A Be pebble (1 cm diameter) multiplier layer surrounds the coolant injection plenum and the coolant flows radially through perforated walls across the bed. Outside the Be layer, a fission fuel layer comprised of depleted uranium contained in Tristructural-isotropic (TRISO) fuel particles

  15. The reflection of airborne UV laser pulses from the ocean

    Science.gov (United States)

    Hoge, F. E.; Krabill, W. B.; Swift, R. N.

    1984-01-01

    It is experimentally shown here for the first time that the normalized laser backscatter cross-section of the sea surface is a function of elevation or height position on teh ocean wave. All data were taken off-nadir, resulting in incidence angles of about 6.5 deg measured relative to the normal to mean sea level (MSL). In the limited data sets analyzed to date, the normalized backscatter cross-section was found to be higher in wave crest regions and lower in wave troughs for a swell-dominated sea over which the wind speed was 5 m/s. The reverse was found to be the case for a sea that was driven by a 14 m/s wind. These isolated results show that the MSL, as measured by an off-nadir and/or multibeam type satellite laser altimeter, will be found above, at, or below the true MSL, depending on the local sea conditions existing in the footprint of the altimeter. Airborne nadir-pointed laser altimeter data for a wide variety of sea conditions are needed before a final determination can be made of the effect of sea state on the backscatter cross-section as measured by a down-looking satellite laser system.

  16. Conceptual design study of the hylife lithium waterfall laser fusion chamber. FY 1978 annual report to Lawrence Livermore Laboratory

    International Nuclear Information System (INIS)

    1978-01-01

    Conceptual design studies of the target chamber defined the general configuration and dimensions of the chamber and the inlet plenum, orifice plate, and nozzle plate concepts required to generate the desired lithium jet fall. Preliminary studies were performed of the target chamber interfaces with the liquid lithium supply system, the laser system, the pellet injection system, and the target chamber mounting and support system. Target chamber environmental effects resulting from typical thermonuclear burns were evaluated. The outlet region of the target chamber was outlined conceptually, and preliminary design considerations were given to the annular graphite reflector regions of the target chamber and the associated liquid lithium coolant passages

  17. Optical design and analysis of carbon dioxide laser fusion systems using interferometry and fast Fourier transform techniques

    International Nuclear Information System (INIS)

    Viswanathan, V.K.

    1979-01-01

    The optical design and analysis of the LASL carbon dioxide laser fusion systems required the use of techniques that are quite different from the currently used method in conventional optical design problems. The necessity for this is explored and the method that has been successfully used at Los Alamos to understand these systems is discussed with examples. This method involves characterization of the various optical components in their mounts by a Zernike polynomial set and using fast Fourier transform techniques to propagate the beam, taking diffraction and other nonlinear effects that occur in these types of systems into account. The various programs used for analysis are briefly discussed

  18. Design and Status of the ELIMED Beam Line for Laser-Driven Ion Beams

    Directory of Open Access Journals (Sweden)

    G. A. Pablo Cirrone

    2015-08-01

    Full Text Available Charged particle acceleration using ultra-intense and ultra-short laser pulses has gathered a strong interest in the scientific community and it is now one of the most attractive topics in the relativistic laser-plasma interaction research. Indeed, it could represent the future of particle acceleration and open new scenarios in multidisciplinary fields, in particular, medical applications. One of the biggest challenges consists of using, in a future perspective, high intensity laser-target interaction to generate high-energy ions for therapeutic purposes, eventually replacing the old paradigm of acceleration, characterized by huge and complex machines. The peculiarities of laser-driven beams led to develop new strategies and advanced techniques for transport, diagnostics and dosimetry of the accelerated particles, due to the wide energy spread, the angular divergence and the extremely intense pulses. In this framework, the realization of the ELIMED (ELI-Beamlines MEDical applications beamline, developed by INFN-LNS (Catania, Italy and installed in 2017 as a part of the ELIMAIA beamline at the ELI-Beamlines (Extreme Light Infrastructure Beamlines facility in Prague, has the aim to investigate the feasibility of using laser-driven ion beams in multidisciplinary applications. ELIMED will represent the first user’s open transport beam line where a controlled laser-driven ion beam will be used for multidisciplinary and medical studies. In this paper, an overview of the beamline, with a detailed description of the main transport elements, will be presented. Moreover, a description of the detectors dedicated to diagnostics and dosimetry will be reported, with some preliminary results obtained both with accelerator-driven and laser-driven beams.

  19. Symmetric grey box identification and distributed beam-based controller design for free-electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Pfeiffer, Sven

    2014-09-15

    The European X-ray Free-Electron Laser (XFEL) at the Deutsches Elektronen Synchtrotron (DESY) in Hamburg will, starting in 2015, open up completely new research opportunities for scientist and industrial users by exploiting ultrashort X-ray laser pulses. Bunches of electrons are accelerated by a radio frequency field inside superconducting cavities up to an energy of 17.5 GeV. A periodic arrangement of magnets forces the accelerated electrons onto a tight slalom path leading to a process in that the electrons emit extremely short and intense X-ray flashes. The generation of equidistant X-ray flashes with a constant intensity requires an extremely high precision field control in combination with beam-based signals. FLASH, which can be seen as a pilot test facility, allows to develop and test controller concepts even before the European XFEL is in operation. In this thesis it is shown that a physical white box model structure, which describes the behavior of each subsystem within the radio frequency field control loop, obeys as first-order approximation the special orthogonal group of dimension two (SO(2)). Presented is a grey box identification approach, which combines the physical model structure with general identification methods. The accelerator modules are operated in a pulsed mode. Thus, the excitation of the system and therefore the identification of the input-output behavior is only possible within a short time period. Developed is an adaptive identification approach with a specified SO(2) symmetric model structure. The proposed controller design strategy fulfills the requirements of a high precision field performance. Adapting the feedforward signal by using an iterative learning control (ILC) algorithm reduces remaining repetitive field errors from pulse to pulse. It is shown, that exploiting the SO(2) symmetric structure and using the developed tensor based ILC representation simplifies the feedforward update computation. Magnetic chicanes, so

  20. Symmetric grey box identification and distributed beam-based controller design for free-electron lasers

    International Nuclear Information System (INIS)

    Pfeiffer, Sven

    2014-09-01

    The European X-ray Free-Electron Laser (XFEL) at the Deutsches Elektronen Synchtrotron (DESY) in Hamburg will, starting in 2015, open up completely new research opportunities for scientist and industrial users by exploiting ultrashort X-ray laser pulses. Bunches of electrons are accelerated by a radio frequency field inside superconducting cavities up to an energy of 17.5 GeV. A periodic arrangement of magnets forces the accelerated electrons onto a tight slalom path leading to a process in that the electrons emit extremely short and intense X-ray flashes. The generation of equidistant X-ray flashes with a constant intensity requires an extremely high precision field control in combination with beam-based signals. FLASH, which can be seen as a pilot test facility, allows to develop and test controller concepts even before the European XFEL is in operation. In this thesis it is shown that a physical white box model structure, which describes the behavior of each subsystem within the radio frequency field control loop, obeys as first-order approximation the special orthogonal group of dimension two (SO(2)). Presented is a grey box identification approach, which combines the physical model structure with general identification methods. The accelerator modules are operated in a pulsed mode. Thus, the excitation of the system and therefore the identification of the input-output behavior is only possible within a short time period. Developed is an adaptive identification approach with a specified SO(2) symmetric model structure. The proposed controller design strategy fulfills the requirements of a high precision field performance. Adapting the feedforward signal by using an iterative learning control (ILC) algorithm reduces remaining repetitive field errors from pulse to pulse. It is shown, that exploiting the SO(2) symmetric structure and using the developed tensor based ILC representation simplifies the feedforward update computation. Magnetic chicanes, so

  1. Use of Zernike polynomials and interferometry in the optical design and assembly of large carbon-dioxide laser systems

    International Nuclear Information System (INIS)

    Viswanathan, V.K.

    1981-01-01

    This paper describes the need for non-raytracing schemes in the optical design and analysis of large carbon-dioxide lasers like the Gigawatt, Gemini, and Helios lasers currently operational at Los Alamos, and the Antares laser fusion system under construction. The scheme currently used at Los Alamos involves characterizing the various optical components with a Zernike polynomial set obtained by the digitization of experimentally produced interferograms of the components. A Fast Fourier Transform code then propagates the complex amplitude and phase of the beam through the whole system and computes the optical parameters of interest. The analysis scheme is illustrated through examples of the Gigawatt, Gemini, and Helios systems. A possible way of using the Zernike polynomials in optical design problems of this type is discussed. Comparisons between the computed values and experimentally obtained results are made and it is concluded that this appears to be a valid approach. As this is a review article, some previously published results are also used where relevant

  2. Design of a bolometer for total-energy measurement of the linear coherent light source pulsed X-ray laser

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, S. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore CA 94550 (United States)]. E-mail: Friedrich1@llnl.gov; Li, L. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore CA 94550 (United States); Ott, L.L. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore CA 94550 (United States); Kolgani, Rajeswari M. [Department of Physics, Geosciences and Astronomy, Towson University, 8000 York Avenue, Towson MD 21252 (United States); Yong, G.J. [Department of Physics, Geosciences and Astronomy, Towson University, 8000 York Avenue, Towson MD 21252 (United States); Ali, Z.A. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore CA 94550 (United States); Drury, O.B. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore CA 94550 (United States); Ables, E. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore CA 94550 (United States); Bionta, R.M. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore CA 94550 (United States)

    2006-04-15

    We are developing a cryogenic bolometer to measure the total energy of the linear coherent light source (LCLS) free electron X-ray laser to be built at the Stanford Linear Accelerator Center. The laser will produce ultrabright X-ray pulses in the energy range between 0.8 and 8 keV with {approx}10{sup 12} photons per {approx}200 fs pulse at a repeat interval of 8 ms, and will be accompanied by a halo of spontaneous undulator radiation. The bolometer is designed to determine the total energy of each laser pulse to within <0.1%, taking into account thermal and mechanical stress to prevent melting in the LCLS beam due to its high energy density. We propose to use a magnetoresistive Nd{sub (1-} {sub x} {sub )}Sr {sub x} MnO{sub 3} sensor array at the metal-insulator transition, where the composition x is adjusted to produce the desired transition temperature. We discuss design considerations and material choices, and present numerical simulations of the thermal response.

  3. High-energy molecular lasers self-controlled volume-discharge lasers and applications

    CERN Document Server

    Apollonov, V V

    2016-01-01

    This book displays the physics and design of high-power molecular lasers. The lasers described are self-controlled volume-discharge lasers. The book explains self-sustained discharge lasers, self-initiated discharge lasers and technical approaches to laser design. Important topics discussed are laser efficiency, laser beam quality and electric field homogeneity. The book contains many new innovative applications.

  4. Recommendations for the design and the installation of large laser scanning microscopy systems

    Science.gov (United States)

    Helm, P. Johannes

    2012-03-01

    Laser Scanning Microscopy (LSM) has since the inventions of the Confocal Scanning Laser Microscope (CLSM) and the Multi Photon Laser Scanning Microscope (MPLSM) developed into an essential tool in contemporary life science and material science. The market provides an increasing number of turn-key and hands-off commercial LSM systems, un-problematic to purchase, set up and integrate even into minor research groups. However, the successful definition, financing, acquisition, installation and effective use of one or more large laser scanning microscopy systems, possibly of core facility character, often requires major efforts by senior staff members of large academic or industrial units. Here, a set of recommendations is presented, which are helpful during the process of establishing large systems for confocal or non-linear laser scanning microscopy as an effective operational resource in the scientific or industrial production process. Besides the description of technical difficulties and possible pitfalls, the article also illuminates some seemingly "less scientific" processes, i.e. the definition of specific laboratory demands, advertisement of the intention to purchase one or more large systems, evaluation of quotations, establishment of contracts and preparation of the local environment and laboratory infrastructure.

  5. Multi-kW single fiber laser based on an extra large mode area fiber design

    Science.gov (United States)

    Langner, Andreas; Such, Mario; Schötz, Gerhard; Just, Florian; Leich, Martin; Schwuchow, Anka; Grimm, Stephan; Zimer, Hagen; Kozak, Marcin; Wedel, Björn; Rehmann, Georg; Bachert, Charley; Krause, Volker

    2012-02-01

    The quality of Yb-doped fused bulk silica produced by sintering of Yb-doped fused silica granulates has improved greatly in the past five years [1 - 4]. In particular, the refractive index and doping level homogeneity of such materials are excellent and we achieved excellent background fiber attenuation of the active core material down to about 20 dB/km at 1200 nm. The improvement of the Yb-doped fused bulk silica has enabled the development of multi-kW fiber laser systems based on a single extra large multimode laser fiber (XLMA fiber). When a single active fiber is used in combination with the XLMA multimode fiber of 1200 μm diameter simple and robust high power fiber laser setups without complex fiber coupling and fiber combiner systems become possible. In this papper, we will discuss in detail the development of the core material based on Yb-doped bulk silica and the characterization of Yb-doped fibers with different core compositions. We will also report on the excellent performance of a 4 kW fiber laser based on a single XLMA-fiber and show the first experimental welding results of steel sheets achieved with such a laser.

  6. Design of a high-gain laser diode-array pumped Nd:YAG Alternating Precessive Slab Amplifier (APS-Amplifier)

    Science.gov (United States)

    Coyle, D. Barry

    1991-01-01

    In the design of space qualifiable laser systems for ranging and altimetry, such as NASA's Geodynamic Laser Ranging System (GLRS), the transmitter must be kept small, powerful yet efficient, and must consist of as few components as possible. A novel preamplifier design is examined which requires no external beam steering optics, yielding a compact component with simple alignment procedures. The gains achieved are comparable to multipass zigzag amplifiers using two or more sets of external optics for extra passes through the amplifying medium.

  7. Motion-free hybrid design laser beam propagation analyzer using a digital micromirror device and a variable focus liquid lens.

    Science.gov (United States)

    Sheikh, Mumtaz; Riza, Nabeel A

    2010-06-01

    To the best of our knowledge, we propose the first motion-free laser beam propagation analyzer with a hybrid design using a digital micromirror device (DMD) and a liquid electronically controlled variable focus lens (ECVFL). Unlike prior analyzers that require profiling the beam at multiple locations along the light propagation axis, the proposed analyzer profiles the beam at the same plane for multiple values of the ECVFL focal length, thus eliminating beam profiler assembly motion. In addition to measuring standard Gaussian beam parameters, the analyzer can also be used to measure the M(2) beam propagation parameter of a multimode beam. Proof-of-concept beam parameter measurements with the proposed analyzer are successfully conducted for a 633 nm laser beam. Given the all-digital nature of the DMD-based profiling and all-analog motion-free nature of the ECVFL beam focus control, the proposed analyzer versus prior art promises better repeatability, speed, and reliability.

  8. Laser and electron-beam powder-bed additive manufacturing of metallic implants: A review on processes, materials and designs.

    Science.gov (United States)

    Sing, Swee Leong; An, Jia; Yeong, Wai Yee; Wiria, Florencia Edith

    2016-03-01

    Additive manufacturing (AM), also commonly known as 3D printing, allows the direct fabrication of functional parts with complex shapes from digital models. In this review, the current progress of two AM processes suitable for metallic orthopaedic implant applications, namely selective laser melting (SLM) and electron beam melting (EBM) are presented. Several critical design factors such as the need for data acquisition for patient-specific design, design dependent porosity for osteo-inductive implants, surface topology of the implants and design for reduction of stress-shielding in implants are discussed. Additive manufactured biomaterials such as 316L stainless steel, titanium-6aluminium-4vanadium (Ti6Al4V) and cobalt-chromium (CoCr) are highlighted. Limitations and future potential of such technologies are also explored. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  9. Conceptual design of an angular multiplexed rare-gas-halide laser-fusion driver. Final technical report, 1 August 1979-31 May 1980

    International Nuclear Information System (INIS)

    Parks, J.H.

    1980-11-01

    A conceptual definition for angular multiplexed rare gas halide drivers was formulated and several design examples analyzed. Angular multiplexed rare gas-halide lasers, in particular the KrF* laser, can be designed to meet ICF requirements. These lasers are scalable, emit at short wavelengths (KrF* 250 nm), and through the use of optical angular multiplexing, produce the required high energy (approx. 1 to 5 MJ) in a short pulse (approx. 10 nsec) with projected overall efficiency in the range of 5 to 7%

  10. Design of the nickel-like tin x-ray laser at 12.0 nm

    International Nuclear Information System (INIS)

    Yan Fei; Zhang Jie; Lu Xin; Zhong, Jia Y.

    2005-01-01

    The effects of the drive laser intensity, pulse duration, and pulse configuration on the performance of the Ni-like Sn x-ray laser at 12.0 nm (4d→4p, J=0→1) are investigated with use of a one-dimensional hydrodynamic code coupled with an atomic physics code. High gain operation is predicted for the optimized drive pulse configuration. The effects of refraction and saturation on the propagation of the x-ray laser in the plasma medium are also investigated by use of a two-dimensional ray-tracing code. The results show that the refraction plays an important role. The saturated output with an effective gain product length of 17.88 can be obtained for an ∼0.40-cm-long plasma column by use of optimized parameters

  11. Design of a compact application-oriented free-electron laser

    Science.gov (United States)

    Chan, K. C. D.; Meier, K.; Nguyen, D.; Sheffield, R.; Wang, T. S.; Warren, R. W.; Wilson, W.; Young, L. M.

    The goal of the Advanced Free-Electron Laser Project at the Los Alamos National Laboratory is to demonstrate that a free-electron laser (FEL) suitable for industrial, medical, and research applications can be built. This FEL system should be efficient, compact, robust, and user-friendly. To achieve this goal, we have incorporated advanced components presently available. Electrons produced by a photoelectron source are accelerated to 20 MeV by a high-brightness accelerator. They are transported by an emittance-preserving beamline with permanent-magnet quadrupoles and dipoles. The electron beam has excellent instantaneous beam quality better than: 2.5 (pi) mm mrad in transverse emittance and 0.3 percent in energy spread at a Peak current up to 310 A. It is used to excite a FEL oscillator with a pulsed-current microwiggler. Including operation at higher harmonics, the laser wavelength extends from 3.7 to 0.4 microns.

  12. National Ignition Facility subsystem design requirements laser and target area building (LTAB) SSDR 1.2.2.1

    International Nuclear Information System (INIS)

    Kempel, P.; Hands, J.

    1996-01-01

    This Subsystem Design Requirements (SSDR) document establishes the performance, design, and verification requirements for the conventional building systems and subsystems of the Laser and Target Area Building (LTAB), including those that house and support the operation of high-energy laser equipment and the operational flow of personnel and materials throughout the facility. This SSDR addresses the following subsystems associated with the LTAB: Building structural systems for the Target Bay, Switchyards, Diagnostic Building, Decontamination Area, Laser Bays, Capacitor Bays and Operations Support Area, and the necessary space associated with building-support equipment; Architectural building features associated with housing the space and with the operational cleanliness of the functional operation of the facilities; Heating, Ventilating, and Air Conditioning (HVAC) systems for maintaining a clean and thermally stable ambient environment within the facilities; Plumbing systems that provide potable water and sanitary facilities for the occupants, plus stormwater drainage for transporting rainwater; Fire Protection systems that guard against fire damage to the facilities and their contents; Material handling systems for transporting personnel and heavy materials within the building areas; Mechanical process piping systems for liquids and gases that provide cooling and other service to experimental laser equipment and components; Electrical power and grounding systems that provide service and standby power to building and experimental equipment, including lighting distribution and communications systems for the facilities; Instrumentation and control systems that ensure the safe operation of conventional facilities systems, such as those listed above. Detailed requirements for building subsystems that are not addressed in this document (such as specific sizes, locations, or capacities) are included in detail-level NIP Project Interface Control Documents (ICDS)

  13. Laser ablation caused by geometrically constrained illumination and inventive target design

    Science.gov (United States)

    Inogamov, N. A.; Zhakhovsky, V. V.; Khokhlov, V. A.

    2018-01-01

    Modern laser technologies use very sophisticated manipulations with (i) a photon cloud forming an irradiation beam and with (ii) disign of a target. E.g. high numerical aperture illumination at very small, diffraction limited conditions is employed for fabrication of the tiny solitary nanoformations on surface of specially prepared thin films deposited onto usually dielectric or semiconductor substrate. In the paper below we list such cases and consider an example with a free standing gold nanofilm modified by tightly focused femtosecond laser pulse.

  14. Joint Laser Interoperability, Tomorrow's Answer to Precision Engagement

    National Research Council Canada - National Science Library

    Neuenswander, David

    2001-01-01

    .... This includes a brief discussion of how a laser works and what constitutes the basic parts of a laser system, laser range finders, laser designators, laser spot trackers, and laser guided weapons...

  15. Design of the energy storage system for the High Energy Gas Laser Facility at LASL

    International Nuclear Information System (INIS)

    Riepe, K.B.; Kircher, M.J.

    1977-01-01

    The Antares laser is being built in the High Energy Gas Laser Facility (HEGLF) at Los Alamos to continue laser fusion experiments at very high power. The laser medium will be pumped by an electrical discharge, which requires an energy input of about 5 MJ in a few microseconds at about 500 kV. The energy storage system which will provide the pulsed power will be a bank of high-voltage pulse-forming networks. Tradeoff studies have been performed comparing the performance of multi-mesh networks with single-mesh networks. The single-mesh network requires about 20% more energy than a two-mesh network, but will tolerate three times the inductance of a two-mesh network. Analysis also shows that amplifier gain is not sensitive to impedance mismatch among the pulse-forming network, the transmission cables, and the gas discharge. A prototype pulse-forming network is being built to test components and trigger performance. It is a Marx generator storing 300 kJ at 1.2 MV open circuit, with 3 μH internal inductance

  16. Anisotropy in semipolar InGaN laser diodes: Consequences for resonator design and facet formation

    Energy Technology Data Exchange (ETDEWEB)

    Rass, Jens; Vogt, Patrick [Technische Universitaet Berlin (Germany). Institute of Solid State Physics; Wernicke, Tim; John, Wilfred; Einfeldt, Sven; Weyers, Markus [Ferdinand-Braun-Institut fuer Hoechstfrequenztechnik, Berlin (Germany); Kneissl, Michael [Technische Universitaet Berlin (Germany). Institute of Solid State Physics; Ferdinand-Braun-Institut fuer Hoechstfrequenztechnik, Berlin (Germany)

    2010-07-01

    For InAlGaN-based light emitting devices on nonpolar and semipolar substrate orientations the polarization fields can be reduced. Birefringence and gain anisotropy influence the optical modes of semipolar separate confinement hetero structures. We have investigated the threshold for amplified spontaneous emission and the optical polarization state of the eigenmodes for laser resonators with different orientations on various semipolar and nonpolar substrates. We found that semipolar resonators along the projection of the c-axis onto the surface have a lower threshold and the light is TE-polarized. Nonpolar resonators perpendicular to the c-axis on the other hand have elevated thresholds and hence a lower gain as well as a tilted linear optical polarization with the electric field nearly parallel to the c-axis of the crystal. In order to obtain devices with low threshold and maximum performance, laser resonators on semipolar substrates have to be oriented along the semipolar orientation, posing a challenge for the fabrication of laser facets. Technologies such as laser assisted cleaving, chemical dry etching and wet chemical post processing are presented and their suitability for the generation of smooth vertical facets is discussed.

  17. Femtosecond laser micromachining of polylactic acid/graphene composites for designing interdigitated microelectrodes for sensor applications

    Science.gov (United States)

    Paula, Kelly T.; Gaál, Gabriel; Almeida, G. F. B.; Andrade, M. B.; Facure, Murilo H. M.; Correa, Daniel S.; Riul, Antonio; Rodrigues, Varlei; Mendonça, Cleber R.

    2018-05-01

    There is an increasing interest in the last years towards electronic applications of graphene-based materials and devices fabricated from patterning techniques, with the ultimate goal of high performance and temporal resolution. Laser micromachining using femtosecond pulses is an attractive methodology to integrate graphene-based materials into functional devices as it allows changes to the focal volume with a submicrometer spatial resolution due to the efficient nonlinear nature of the absorption, yielding rapid prototyping for innovative applications. We present here the patterning of PLA-graphene films spin-coated on a glass substrate using a fs-laser at moderate pulse energies to fabricate interdigitated electrodes having a minimum spatial resolution of 5 μm. Raman spectroscopy of the PLA-graphene films indicated the presence of multilayered graphene fibers. Subsequently, the PLA-graphene films were micromachined using a femtosecond laser oscillator delivering 50-fs pulses and 800 nm, where the pulse energy and scanning speed was varied in order to determine the optimum irradiation parameters (16 nJ and 100 μm/s) to the fabrication of microstructures. The micromachined patterns were characterized by optical microscopy and submitted to electrical measurements in liquid samples, clearly distinguishing all tastes tested. Our results confirm the femtosecond laser micromachining technique as an interesting approach to efficiently pattern PLA-graphene filaments with high precision and minimal mechanical defects, allowing the easy fabrication of interdigitated structures and an alternative method to those produced by conventional photolithography.

  18. Design of photonic crystal surface emitting lasers with indium-tin-oxide top claddings

    Science.gov (United States)

    Huang, Shen-Che; Hong, Kuo-Bin; Chiu, Han-Lun; Lan, Shao-Wun; Chang, Tsu-Chi; Li, Heng; Lu, Tien-Chang

    2018-02-01

    Electrically pumped GaAs-based photonic crystal surface emitting lasers were fabricated using a simple fabrication process by directly capping the indium-tin-oxide transparent conducting thin film as the top cladding layer upon a photonic crystal layer. Optimization of the separate-confinement heterostructures of a laser structure is crucial to improving characteristics by providing advantageous optical confinements. The turn-on voltage, series resistance, threshold current, and slope efficiency of the laser with a 100 × 100 μm2 photonic crystal area operated at room temperature were 1.3 V, 1.5 Ω, 121 mA, and 0.2 W/A, respectively. Furthermore, we demonstrated a single-lobed lasing wavelength of 928.6 nm at 200 mA and a wavelength redshift rate of 0.05 nm/K in temperature-dependent measurements. The device exhibited the maximum output power of approximately 400 mW at an injection current of 2 A; moreover, divergence angles of less than 1° for the unpolarized circular-shaped laser beam were measured at various injection currents. Overall, the low threshold current, excellent beam quality, small divergence, high output power, and high-operating-temperature (up to 343 K) of our devices indicate that they can potentially fill the requirements for next-generation light sources and optoelectronic devices.

  19. Image-guided macular laser therapy: design considerations and progress toward implementation

    Science.gov (United States)

    Berger, Jeffrey W.; Shin, David S.

    1999-06-01

    Laser therapy is currently the only treatment of proven benefit for exudative age related macular degeneration and diabetic retinopathy. To guide treatment for macular diseases, investigations were initiated to permit overlay of previously-stored angiographic images and image sequences superimposed onto the real-time biomicroscopic fundus image. Prior to treatment, a set of partially overlapping fundus images is acquired and montaged in order to provide a map for subsequent tracking operations. A binocular slit-lamp biomicroscope interfaced to a CCD camera, framegrabber board, and PC permits acquisition and rendering of retinal images. Computer-vision algorithms facilitate robust tracking, registration, and near-video-rate image overlay of previously-stored retinal photographic and angiographic images onto the real-time fundus image. Laser treatment is guided in this augmented reality environment where the borders of the treatment target--for example, the boundaries of a choroidal neovascularization complex--are easily identified through overlay of angiographic information superimposed on, and registered with, the real-time fundus image. During periods of misregistration as judged by the amplitude of the tracking similarity metric, laser function is disabled, affording additional safety. Image-guided macular laser therapy should facilitate accurate targeting of treatable lesions and less unintentional retinal injury when compared with standard techniques.

  20. Signatures of Kelvin and Rossby wave propagation in the northern Indian Ocean from TOPEX/POSEIDON Altimeter

    Digital Repository Service at National Institute of Oceanography (India)

    PrasannaKumar, S.; Unnikrishnan, A.S.; Muraleedharan, P.M.

    The climatological monthly mean sea surface height (SSH) anomalies derived from T/P altimeter in the northern Indian Ocean, during 1993 to 1997, are used to prepare time-longitude plots. Along the equator they reveal strong semi-annual variability...

  1. Does the Laser-Microtextured Short Implant Collar Design Reduce Marginal Bone Loss in Comparison with a Machined Collar?

    Directory of Open Access Journals (Sweden)

    B. Alper Gultekin

    2016-01-01

    Full Text Available Purpose. To compare marginal bone loss between subgingivally placed short-collar implants with machined collars and those with machined and laser-microtextured collars. Materials and Methods. The investigators used a retrospective study design and included patients who needed missing posterior teeth replaced with implants. Short-collar implants with identical geometries were divided into two groups: an M group, machined collar; and an L group, machined and laser-microtextured collar. Implants were evaluated according to marginal bone loss, implant success, and probing depth (PD at 3 years of follow-up. Results. Sixty-two patients received 103 implants (56 in the M group and 47 in the L group. The cumulative survival rate was 100%. All implants showed clinically acceptable marginal bone loss, although bone resorption was lower in the L group (0.49 mm than in the M group (1.38 mm at 3 years (p<0.01. A significantly shallower PD was found for the implants in the L group during follow-up (p<0.01. Conclusions. Our results suggest predictable outcomes with regard to bone loss for both groups; however, bone resorption was less in the L group than in the M group before and after loading. The laser-microtextured collar implant may provide a shallower PD than the machined collar implant.

  2. ACCELERATION OF SEA LEVEL RISE OVER MALAYSIAN SEAS FROM SATELLITE ALTIMETER

    Directory of Open Access Journals (Sweden)

    A. I. A. Hamid

    2016-09-01

    Full Text Available Sea level rise becomes our concern nowadays as a result of variously contribution of climate change that cause by the anthropogenic effects. Global sea levels have been rising through the past century and are projected to rise at an accelerated rate throughout the 21st century. Due to this change, sea level is now constantly rising and eventually will threaten many low-lying and unprotected coastal areas in many ways. This paper is proposing a significant effort to quantify the sea level trend over Malaysian seas based on the combination of multi-mission satellite altimeters over a period of 23 years. Eight altimeter missions are used to derive the absolute sea level from Radar Altimeter Database System (RADS. Data verification is then carried out to verify the satellite derived sea level rise data with tidal data. Eight selected tide gauge stations from Peninsular Malaysia, Sabah and Sarawak are chosen for this data verification. The pattern and correlation of both measurements of sea level anomalies (SLA are evaluated over the same period in each area in order to produce comparable results. Afterwards, the time series of the sea level trend is quantified using robust fit regression analysis. The findings clearly show that the absolute sea level trend is rising and varying over the Malaysian seas with the rate of sea level varies and gradually increase from east to west of Malaysia. Highly confident and correlation level of the 23 years measurement data with an astonishing root mean square difference permits the absolute sea level trend of the Malaysian seas has raised at the rate 3.14 ± 0.12 mm yr-1 to 4.81 ± 0.15 mm yr-1 for the chosen sub-areas, with an overall mean of 4.09 ± 0.12 mm yr-1. This study hopefully offers a beneficial sea level information to be applied in a wide range of related environmental and climatology issue such as flood and global warming.

  3. Acceleration of Sea Level Rise Over Malaysian Seas from Satellite Altimeter

    Science.gov (United States)

    Hamid, A. I. A.; Din, A. H. M.; Khalid, N. F.; Omar, K. M.

    2016-09-01

    Sea level rise becomes our concern nowadays as a result of variously contribution of climate change that cause by the anthropogenic effects. Global sea levels have been rising through the past century and are projected to rise at an accelerated rate throughout the 21st century. Due to this change, sea level is now constantly rising and eventually will threaten many low-lying and unprotected coastal areas in many ways. This paper is proposing a significant effort to quantify the sea level trend over Malaysian seas based on the combination of multi-mission satellite altimeters over a period of 23 years. Eight altimeter missions are used to derive the absolute sea level from Radar Altimeter Database System (RADS). Data verification is then carried out to verify the satellite derived sea level rise data with tidal data. Eight selected tide gauge stations from Peninsular Malaysia, Sabah and Sarawak are chosen for this data verification. The pattern and correlation of both measurements of sea level anomalies (SLA) are evaluated over the same period in each area in order to produce comparable results. Afterwards, the time series of the sea level trend is quantified using robust fit regression analysis. The findings clearly show that the absolute sea level trend is rising and varying over the Malaysian seas with the rate of sea level varies and gradually increase from east to west of Malaysia. Highly confident and correlation level of the 23 years measurement data with an astonishing root mean square difference permits the absolute sea level trend of the Malaysian seas has raised at the rate 3.14 ± 0.12 mm yr-1 to 4.81 ± 0.15 mm yr-1 for the chosen sub-areas, with an overall mean of 4.09 ± 0.12 mm yr-1. This study hopefully offers a beneficial sea level information to be applied in a wide range of related environmental and climatology issue such as flood and global warming.

  4. No pain: no gain: The complex art of soft x-ray laser target design and analysis

    International Nuclear Information System (INIS)

    Rosen, M.D.; London, R.A.; Hagelstein, P.L.

    1988-01-01

    We review our methodologies in the design and analysis of soft x-ray laser experiments. We convolve large scale 2-D hydro code output with detailed atomic data bases in a kinetics code with 1-D or 2-D line transfer. The time and space dependent level population data is then post processed further with a beam transport code, including refraction, to predict actual experimental results. While mysteries do remain, we present many examples that show how this complex modeling procedure is crucial in explaining experimental results

  5. No pain-no gain: The complex art of soft x-ray laser target design and analysis

    International Nuclear Information System (INIS)

    Rosen, M.D.; London, R.A.; Hagelstein, P.L.

    1988-01-01

    We review our methodologies in the design and analysis of soft x-ray laser experiments. We convolve large-scale 2-D hydro code output with detailed atomic data bases in a kinetics code with 1-D or 2-D line transfer. The time and space dependent level population data is then post processed further with a beam transport code, including refraction, to predict actual experimental results. While mysteries do remain, we present many examples that show how this complex modeling procedure is crucial in explaining experimental results. 23 refs., 8 figs., 1 tab

  6. Photodetection of early cancer by laser-induced fluorescence of a tumor-selective dye: apparatus design and realization

    Science.gov (United States)

    Wagnieres, Georges A.; Depeursinge, Christian D.; Monnier, Philippe; Savary, Jean-Francois; Cornaz, Piet F.; Chatelain, Andre; van den Bergh, Hubert

    1990-07-01

    An apparatus is designed and realized to detect "early" cancer at the surface of the hollow organs in the human body by endoscopic means. The tumor is localized by the laser induced fluorescence of a dye (HPD) which concentrates selectively in the neoplastic tissue after intravenous injection. Fluorescence contrast between the tumor and its normal surroundings is enhanced by subtracting the background autofluorescence which occurs in both types of tissue. This is done by means of 2-color digital images manipulation in real-time. Preliminary clinical tests of the apparatus demonstrated the detection of carcinoma in situ in the esophagus.

  7. Influence of interface conditions on laser diode ignition of pyrotechnic mixtures: application to the design of an ignition device

    Energy Technology Data Exchange (ETDEWEB)

    Opdebeck, Frederic; Gillard, Philippe [Laboratoire Energetique Explosions et Structures de l' Universite d' Orleans, 63 boulevard de Lattre de Tassigny, 18020 cedex, Bourges (France); Radenac, D' Erwann [Laboratoire de combustion et de detonique, ENSMA, BP 109, 86960 cedex, Futuroscope (France)

    2003-01-01

    This paper treats of numerical modelling which simulates the laser ignition of pyrotechnic mixtures. The computation zone is divided into two fields. The first is used to take account of the heat loss with the outside. It can represent an optical fibre or a sapphire protective porthole. The second field represents the reactive tablet which absorbs the laser diode's beam. A specific feature of the model is that it incorporates a thermal contact resistance R{sub c} between the two computation fields. Through knowledge of the thermal, optical and kinetic properties, this code makes it possible to compute the ignition conditions. The latter are defined by the energy E{sub 50} and the time t{sub i} of ignition of any pyrotechnic mixture and for various ignition systems.This work was validated in the case of an ignition system consisting of a laser diode with an optical lens re-focussing system. The reactive tablet contains 62% by mass of iron and 38% by mass of KClO{sub 4}. Its porosity is 25.8%. After an evaluation of the laser's coefficient of absorption, the variations of the ignition parameters E{sub 50} and t{sub i} are studied as a function of the thermal contact resistance R{sub c}. Temperature profiles are obtained as a function of time and for various values of the thermal contact resistance R{sub c}. More fundamental observations are made concerning the position of the hot spot corresponding to priming. From this study, which concerns the heat exchange between the two media, several practical conclusions are given concerning the design of an ignition device. By evaluation of the thermal contact resistance R{sub c}, comparison with test results becomes possible and the results of the computations are in reasonable agreement with the test measurements. (authors)

  8. Laser-induced spin protection and switching in a specially designed magnetic dot: A theoretical investigation

    Science.gov (United States)

    Zhang, G. P.; Si, M. S.; George, T. F.

    2011-04-01

    Most laser-induced femtosecond magnetism investigations are done in magnetic thin films. Nanostructured magnetic dots, with their reduced dimensionality, present new opportunities for spin manipulation. Here we predict that if a magnetic dot has a dipole-forbidden transition between the lowest occupied molecular orbital (LUMO) and the highest unoccupied molecular orbital (HOMO), but a dipole-allowed transition between LUMO+1 and HOMO, electromagnetically induced transparency can be used to prevent ultrafast laser-induced spin momentum reduction, or spin protection. This is realized through a strong dump pulse to funnel the population into LUMO+1. If the time delay between the pump and dump pulses is longer than 60 fs, a population inversion starts and spin switching is achieved. These predictions are detectable experimentally.

  9. Optimal design of similariton fiber lasers without gain-bandwidth limitation.

    Science.gov (United States)

    Li, Xingliang; Zhang, Shumin; Yang, Zhenjun

    2017-07-24

    We have numerically investigated broadband high-energy similariton fiber lasers, demonstrated that the self-similar evolution of pulses can locate in a segment of photonic crystal fiber without gain-bandwidth limitation. The effects of various parameters, including the cavity length, the spectral filter bandwidth, the pump power, the length of the photonic crystal fiber and the output coupling ratio have also been studied in detail. Using the optimal parameters, a single pulse with spectral width of 186.6 nm, pulse energy of 23.8 nJ, dechirped pulse duration of 22.5 fs and dechirped pulse peak power of 1.26 MW was obtained. We believe that this detailed analysis of the behaviour of pulses in the similariton regime may have major implications in the development of broadband high-energy fiber lasers.

  10. Design of Extended Depth-of-Focus Laser Beams Using Orthogonal Beam Expansions

    Directory of Open Access Journals (Sweden)

    Leonard Bergstein

    2005-06-01

    Full Text Available Laser beams with extended depth of focus have many practical applications, such as scanning printed bar codes. Previous work has concentrated on synthesizing such beams by approximating the nondiffracting Bessel beam solution to the wave equation. In this paper, we introduce an alternate novel synthesis method that is based on maintaining a minimum MTF value (contrast over the largest possible distance. To achieve this, the coefficients of an orthogonal beam expansion are sequentially optimized to this criterion. One of the main advantages of this method is that it can be easily generalized to noncircularly symmetrical beams by the appropriate choice of the beam expansion basis functions. This approach is found to be very useful for applications that involve scanning of the laser beam.

  11. Experimental Design of a UCAV-Based High-Energy Laser Weapon

    Science.gov (United States)

    2016-12-01

    opportunity to participate as a speaker to the Advanced High-Power Laser Conference in Colorado Springs, CO, in June 2016. Special gratitude to Dr...et al. 2010). Specifically, water vapor, due to its geometric structure and its multiple vibrational modes, is the greater contributor to...well as jitter (caused by the platform’s vibrations ), though, the overall “quality” of the beam is poorer and the effective spot size now defined as

  12. LUX - A design study for a linac/laser-based ultrafast X-ray source

    Energy Technology Data Exchange (ETDEWEB)

    Corlett, J.N.; Barletta, W.A.; DeSantis, S.; Doolittle, L.; Fawley, W.M.; Heimann, P.; Leone, S.; Lidia, S.; Li, D.; Penn, G.; Ratti, A.; Reinsch, M.; Schoenlein, R.; Staples, J.; Stover, G.; Virostek, S.; Wan, W.; Wells, R.; Wilcox, R.; Wolski, A.; Wurtele, J.; Zholents, A.

    2004-08-06

    A warm, relativistic fluid theory of a nonequilibrium, collisionless plasma is developed to analyze nonlinear plasma waves excited by intense drive beams. The maximum amplitude and wavelength are calculated for nonrelativistic plasma temperatures and arbitrary plasma wave phase velocities. The maximum amplitude is shown to increase in the presence of a laser field. These results set a limit to the achievable gradient in plasma-based accelerators.

  13. LUX - A design study for a linac/laser-based ultrafast X-ray source

    International Nuclear Information System (INIS)

    Corlett, J.N.; Barletta, W.A.; DeSantis, S.; Doolittle, L.; Fawley, W.M.; Heimann, P.; Leone, S.; Lidia, S.; Li, D.; Penn, G.; Ratti, A.; Reinsch, M.; Schoenlein, R.; Staples, J.; Stover, G.; Virostek, S.; Wan, W.; Wells, R.; Wilcox, R.; Wolski, A.; Wurtele, J.; Zholents, A.

    2004-01-01

    A warm, relativistic fluid theory of a nonequilibrium, collisionless plasma is developed to analyze nonlinear plasma waves excited by intense drive beams. The maximum amplitude and wavelength are calculated for nonrelativistic plasma temperatures and arbitrary plasma wave phase velocities. The maximum amplitude is shown to increase in the presence of a laser field. These results set a limit to the achievable gradient in plasma-based accelerators

  14. Qualification of an evaluated butterfly-packaged DFB laser designed for space applications

    Science.gov (United States)

    Tornow, S.; Stier, C.; Buettner, T.; Laurent, T.; Kneier, M.; Bru, J.; Lien, Y.

    2017-11-01

    An extended qualification program has proven the quality of a previously evaluated semiconductor laser diode, which is intended to be used in a subsystem for the GAIA mission. We report on results of several reliability tests performed in subgroups. The requirements of the procurement specification with respect to reliability and desired manufacturing processes were confirmed. This is an example for successful collaboration between component supplier, system integrator and payload responsible party.

  15. Laser Technology in Interplanetary Exploration: The Past and the Future

    Science.gov (United States)

    Smith, David E.

    2000-01-01

    Laser technology has been used in planetary exploration for many years but it has only been in the last decade that laser altimeters and ranging systems have been selected as flight instruments alongside cameras, spectrometers, magnetometers, etc. Today we have an active laser system operating at Mars and another destined for the asteroid Eros. A few years ago a laser ranging system on the Clementine mission changed much of our thinking about the moon and in a few years laser altimeters will be on their way to Mercury, and also to Europa. Along with the increased capabilities and reliability of laser systems has came the realization that precision ranging to the surface of planetary bodies from orbiting spacecraft enables more scientific problems to be addressed, including many associated with planetary rotation, librations, and tides. In addition, new Earth-based laser ranging systems working with similar systems on other planetary bodies in an asynchronous transponder mode will be able to make interplanetary ranging measurements at the few cm level and will advance our understanding of solar system dynamics and relativistic physics.

  16. Design of a compact application-oriented free-electron laser

    International Nuclear Information System (INIS)

    Chan, K.C.D.; Meier, K.; Nguyen, D.; Sheffield, R.; Wang, T.S.; Warren, R.W.; Wilson, W.; Young, L.M.

    1992-01-01

    The goal of the Advanced Free-Electron Laser Project at the Los Alamos National Laboratory is to demonstrate that a free-electron laser (FEL) suitable for industrial, medical, and research applications can be built. This FEL system should be efficient, compact, robust, and user-friendly. To achieve this goal, we have incorporated advanced components presently available. Electrons produced by a photoelectron source are accelerated to 20 MeV by a high-brightness accelerator. They are transported by an emittance-preserving beamline with permanent-magnet quadrupoles and dipoles. The electron beam has excellent instantaneous beam quality better than: 2.5 π mm mrad in transverse emittance and 0.3% in energy spread at a Peak current up to 310 A. It is used to excite a FEL oscillator with a pulsed-current microwiggler. Including operation at higher harmonics, the laser wavelength extends from 3.7 μm to 0.4 μm

  17. Laser-generated shock wave attenuation aimed at microscale pyrotechnic device design

    Directory of Open Access Journals (Sweden)

    Hyeonju Yu

    2016-05-01

    Full Text Available To meet the rising demand for miniaturizing the pyrotechnic device that consists of donor/acceptor pair separated by a bulkhead or a thin gap, the shock initiation sensitivity in the microscale gap test configuration is investigated. For understanding the shock attenuation within a gap sample (304 stainless steel thickness of 10∼800 μm, the laser-generated shock wave in water confinement is adopted. The shock properties are obtained from the free surface velocity by making use of a velocity interferometer system for any reflector (VISAR. Analytical models for plasma generation in a confined geometry and for evolution and decay of shock waves during the propagation are considered. The shape and amplitude of the laser-driven initial pressure load and its attenuation pattern in the gap are effectively controlled for targeting the microscale propagation distance and subsequent triggering pressure for the acceptor charge. The reported results are important in the precise controlling of the shock strength during the laser initiation of microscale pyrotechnic devices.

  18. Low-stress mounting configuration design for large aperture laser transport mirror

    Science.gov (United States)

    Zhang, Zheng; Quan, Xusong; Yao, Chao; Wang, Hui

    2016-10-01

    TM1-6S1 large aperture laser transport mirror is a crucial optical unit of high power solid-state laser in the Inertial Confinement Fusion (ICF) facility. This article focuses on the low-stress and precise mounting method of large-aperture mirror. Based on the engineering practice of SG-III, the state-of-the-art and key problems of current mounting configuration are clarified firstly. Subsequently, a brand new low-stress mounting configuration with flexure supports is proposed. Opto-mechanical model of the mirror under mounting force is built up with elastic mechanics theory. Further, numerical methods and field tests are employed to verify the favorable load uniform capacity and load adjust capacity of flexure supports. With FEM, the relation between the mounting force from new configuration and the mirror surface distortion (wavefront error) is clarified. The novel mounting method of large aperture optics could be not only used on this laser transport mirror, but also on the other transmission optics and large crystals in ICF facilities.

  19. Climate-change-driven accelerated sea-level rise detected in the altimeter era.

    Science.gov (United States)

    Nerem, R S; Beckley, B D; Fasullo, J T; Hamlington, B D; Masters, D; Mitchum, G T

    2018-02-27

    Using a 25-y time series of precision satellite altimeter data from TOPEX/Poseidon, Jason-1, Jason-2, and Jason-3, we estimate the climate-change-driven acceleration of global mean sea level over the last 25 y to be 0.084 ± 0.025 mm/y 2 Coupled with the average climate-change-driven rate of sea level rise over these same 25 y of 2.9 mm/y, simple extrapolation of the quadratic implies global mean sea level could rise 65 ± 12 cm by 2100 compared with 2005, roughly in agreement with the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5) model projections. Copyright © 2018 the Author(s). Published by PNAS.

  20. Corrections for the effects of significant wave height and attitude on Geosat radar altimeter measurements

    Science.gov (United States)

    Hayne, G. S.; Hancock, D. W., III

    1990-01-01

    Range estimates from a radar altimeter have biases which are a function of the significant wave height (SWH) and the satellite attitude angle (AA). Based on results of prelaunch Geosat modeling and simulation, a correction for SWH and AA was already applied to the sea-surface height estimates from Geosat's production data processing. By fitting a detailed model radar return waveform to Geosat waveform sampler data, it is possible to provide independent estimates of the height bias, the SWH, and the AA. The waveform fitting has been carried out for 10-sec averages of Geosat waveform sampler data over a wide range of SWH and AA values. The results confirm that Geosat sea-surface-height correction is good to well within the original dm-level specification, but that an additional height correction can be made at the level of several cm.

  1. Design and realization of a hard X-ray prototype imager with spectral selection for the Laser MegaJoule

    International Nuclear Information System (INIS)

    Dennetiere, David

    2012-01-01

    In the Laser MegaJoule (LMJ) project context, measurements need to be done by diagnostics in order to achieve ignition. Amongst these diagnostics, some of the X-ray imagers will have to observe hydrodynamics instabilities on the micron balloon surface. X-ray radiography or self-emission imaging are the techniques used to obtain such imaging. None of the existing X-ray imagers designed for LMJ is currently able to record this kind of image. The X-ray imager designed during this thesis will have to achieve a high resolution image at high energy and will have to meet all the requirements subsequent to its use on a large facility like LMJ. We have studied and optimized an already existing diagnostic: EHRXI. We have extended its covered spectral range up to 12 keV. We measured its resolution that is under 5 μm in a 1 mm diameter field of view. This diagnostic has been successfully used on laser experiments in ELFIE 100 TW and OMEGA. After analyzing the performances and weaknesses of EHRXI, we were able to design a LMJ diagnostic prototype: Merssix. This microscope will achieve a resolution under 5 μm in a 500 μm diameter field of view with a covered spectral range up to 22 keV. Merssix has been specifically designed for LMJ and adapted to fit its experimental framework. Its design allows it in particular to be used for radiography in a complex X-ray producing environment. (author) [fr

  2. Design study of high gradient, low impedance accelerating structures for the FERMI free electron laser linac upgrade

    Science.gov (United States)

    Shafqat, N.; Di Mitri, S.; Serpico, C.; Nicastro, S.

    2017-09-01

    The FERMI free-electron laser (FEL) of Elettra Sincrotrone Trieste, Italy, is a user facility driven by a 1.5 GeV 10-50 Hz S-band radiofrequency linear accelerator (linac), and it is based on an external laser seeding scheme that allows lasing at the shortest fundamental wavelength of 4 nm. An increase of the beam energy to 1.8 GeV at a tolerable breakdown rate, and an improvement of the final beam quality is desired in order to allow either lasing at 4 nm with a higher flux, or lasing at shorter wavelengths. This article presents the impedance analysis of newly designed S-band accelerating structures, for replacement of the existing backward travelling wave structures (BTWS) in the last portion of the FERMI linac. The new structure design promises higher accelerating gradient and lower impedance than those of the existing BTWS. Particle tracking simulations show that, with the linac upgrade, the beam relative energy spread, its linear and nonlinear z-correlation internal to the bunch, and the beam transverse emittances can be made smaller than the ones in the present configuration, with expected advantage to the FEL performance. The repercussion of the upgrade on the linac quadrupole magnets setting, for a pre-determined electron beam optics, is also considered.

  3. Free electron lasers for 13nm EUV lithography: RF design strategies to minimise investment and operational costs

    Science.gov (United States)

    Keens, Simon; Rossa, Bernhard; Frei, Marcel

    2016-03-01

    As the semiconductor industry proceeds to develop ever better sources of extreme ultraviolet (EUV) light for photolithography applications, two distinct technologies have come to prominence: Tin-plasma and free electron laser (FEL) sources. Tin plasma sources have been in development within the industry for many years, and have been widely reported. Meanwhile, FELs represent the most promising alternative to create high power EUV frequencies and, while tin-plasma source development has been ongoing, such lasers have been continuously developed by academic institutions for use in fundamental research programmes in conjunction with universities and national scientific institutions. This paper follows developments in the field of academic FELs, and presents information regarding novel technologies, specifically in the area of RF design strategy, that may be incorporated into future industrial FEL systems for EUV lithography in order to minimize the necessary investment and operational costs. It goes on to try to assess the cost-benefit of an alternate RF design strategy, based upon previous studies.

  4. Low power laser driver design in 28nm CMOS for on-chip and chip-to-chip optical interconnect

    Science.gov (United States)

    Belfiore, Guido; Szilagyi, Laszlo; Henker, Ronny; Ellinger, Frank

    2015-09-01

    This paper discusses the challenges and the trade-offs in the design of laser drivers for very-short distance optical communications. A prototype integrated circuit is designed and fabricated in 28 nm super-low-power CMOS technology. The power consumption of the transmitter is 17.2 mW excluding the VCSEL that in our test has a DC power consumption of 10 mW. The active area of the driver is only 0.0045 mm2. The driver can achieve an error-free (BER < 10 -12) electrical data-rate of 25 Gbit/s using a pseudo random bit sequence of 27 -1. When the driver is connected to the VCSEL module an open optical eye is reported at 15 Gbit/s. In the tested bias point the VCSEL module has a measured bandwidth of 10.7 GHz.

  5. Assessment of NASA airborne laser altimetry data using ground-based GPS data near Summit Station, Greenland

    Science.gov (United States)

    Brunt, Kelly M.; Hawley, Robert L.; Lutz, Eric R.; Studinger, Michael; Sonntag, John G.; Hofton, Michelle A.; Andrews, Lauren C.; Neumann, Thomas A.

    2017-03-01

    A series of NASA airborne lidars have been used in support of satellite laser altimetry missions. These airborne laser altimeters have been deployed for satellite instrument development, for spaceborne data validation, and to bridge the data gap between satellite missions. We used data from ground-based Global Positioning System (GPS) surveys of an 11 km long track near Summit Station, Greenland, to assess the surface-elevation bias and measurement precision of three airborne laser altimeters including the Airborne Topographic Mapper (ATM), the Land, Vegetation, and Ice Sensor (LVIS), and the Multiple Altimeter Beam Experimental Lidar (MABEL). Ground-based GPS data from the monthly ground-based traverses, which commenced in 2006, allowed for the assessment of nine airborne lidar surveys associated with ATM and LVIS between 2007 and 2016. Surface-elevation biases for these altimeters - over the flat, ice-sheet interior - are less than 0.12 m, while assessments of measurement precision are 0.09 m or better. Ground-based GPS positions determined both with and without differential post-processing techniques provided internally consistent solutions. Results from the analyses of ground-based and airborne data provide validation strategy guidance for the Ice, Cloud, and land Elevation Satellite 2 (ICESat-2) elevation and elevation-change data products.

  6. Influence of laser design parameters on the hydrodynamics of microfusion plasmas

    International Nuclear Information System (INIS)

    Sanmartin, J. A.; Barrero, A.

    1976-01-01

    The quasi neutral, one dimensional motion generated in a cold, infinite, uniform plasma of density n 0 , by the absorption, In a given plane, of a linear pulse of energy per unit time and area φ - φ 0 t/τ, 0 t o(n 2 0 τ/φ 0 ) 2 /3. Detailed asymptotic results are obtained for both α >1; the general (behaviour of the solution for arbitrary α is discussed. The analysis can be easily extended to the case of a plasma initially occupying a half-space, and throws light on the hydrodynamics of laser fusion plasmas. (Author) 51 refs

  7. Centroid stabilization for laser alignment to corner cubes: designing a matched filter

    Energy Technology Data Exchange (ETDEWEB)

    Awwal, Abdul A. S.; Bliss, Erlan; Brunton, Gordon; Kamm, Victoria Miller; Leach, Richard R.; Lowe-Webb, Roger; Roberts, Randy; Wilhelmsen, Karl

    2016-11-08

    Automation of image-based alignment of National Ignition Facility high energy laser beams is providing the capability of executing multiple target shots per day. One important alignment is beam centration through the second and third harmonic generating crystals in the final optics assembly (FOA), which employs two retroreflecting corner cubes as centering references for each beam. Beam-to-beam variations and systematic beam changes over time in the FOA corner cube images can lead to a reduction in accuracy as well as increased convergence durations for the template-based position detector. A systematic approach is described that maintains FOA corner cube templates and guarantees stable position estimation.

  8. Design of a petawatt optical parametric chirped pulse amplification upgrade of the kilojoule iodine laser PALS

    Czech Academy of Sciences Publication Activity Database

    Novák, Ondřej; Divoký, Martin; Turčičová, Hana; Straka, Petr

    2013-01-01

    Roč. 31, č. 2 (2013), s. 211-218 ISSN 0263-0346 R&D Projects: GA ČR GA202/06/0814; GA MŠk(CZ) LC528; GA MŠk LN00A100 EU Projects: European Commission(XE) 506350 - LASERLAB-EUROPE Institutional support: RVO:68378271 Keywords : VULCAN petawatt * system * prospects * facility * program Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.701, year: 2013 http://journals.cambridge.org/action/displayAbstract?fromPage=online& aid =8950936

  9. Radiation effects on optical components of a laser radar sensor designed for remote metrology in ITER

    International Nuclear Information System (INIS)

    Menon, M.M.; Grann, E.B.; Slotwinski, A.

    1997-09-01

    A frequency modulated laser radar is being developed for in-vessel metrology and viewing of plasma-facing surfaces. Some optical components of this sensor must withstand intense gamma radiation (3 x 10 6 rad/h) during operation. The authors have tested the effect of radiation on a silica core polarization maintaining optical fiber and on TeO 2 crystals at doses up to ∼ 10 9 rad. Additional tests are planned for evaluating the performance of a complete acousto-optic (AO) scanning device. The progress made in these tests is also described

  10. Design optimization of a compact photonic crystal microcavity based on slow light and dispersion engineering for the miniaturization of integrated mode-locked lasers

    Directory of Open Access Journals (Sweden)

    Malik Kemiche

    2018-01-01

    Full Text Available We exploit slow light (high ng modes in planar photonic crystals in order to design a compact cavity, which provides an attractive path towards the miniaturization of near-infrared integrated fast pulsed lasers. By applying dispersion engineering techniques, we can design structures with a low dispersion, as needed by mode-locking operation. Our basic InP SiO2 heterostructure is robust and well suited to integrated laser applications. We show that an optimized 30 μm long cavity design yields 9 frequency-equidistant modes with a FSR of 178 GHz within a 11.5 nm bandwidth, which could potentially sustain the generation of optical pulses shorter than 700 fs. In addition, the numerically calculated quality factors of these modes are all above 10,000, making them suitable for reaching laser operation. Thanks to the use of a high group index (28, this cavity design is almost one order of magnitude shorter than standard rib-waveguide based mode-locked lasers. The use of slow light modes in planar photonic crystal based cavities thus relaxes the usual constraints that tightly link the device size and the quality (peak power, repetition rate of the pulsed laser signal.

  11. Design optimization of a compact photonic crystal microcavity based on slow light and dispersion engineering for the miniaturization of integrated mode-locked lasers

    Science.gov (United States)

    Kemiche, Malik; Lhuillier, Jérémy; Callard, Ségolène; Monat, Christelle

    2018-01-01

    We exploit slow light (high ng) modes in planar photonic crystals in order to design a compact cavity, which provides an attractive path towards the miniaturization of near-infrared integrated fast pulsed lasers. By applying dispersion engineering techniques, we can design structures with a low dispersion, as needed by mode-locking operation. Our basic InP SiO2 heterostructure is robust and well suited to integrated laser applications. We show that an optimized 30 μm long cavity design yields 9 frequency-equidistant modes with a FSR of 178 GHz within a 11.5 nm bandwidth, which could potentially sustain the generation of optical pulses shorter than 700 fs. In addition, the numerically calculated quality factors of these modes are all above 10,000, making them suitable for reaching laser operation. Thanks to the use of a high group index (28), this cavity design is almost one order of magnitude shorter than standard rib-waveguide based mode-locked lasers. The use of slow light modes in planar photonic crystal based cavities thus relaxes the usual constraints that tightly link the device size and the quality (peak power, repetition rate) of the pulsed laser signal.

  12. Geosat altimeter derived sea surface wind speeds and significant wave heights for the north Indian Ocean and their comparison with in situ data

    Digital Repository Service at National Institute of Oceanography (India)

    Vethamony, P.; Vaithiyanathan, R.; Almeida, A.M.; Santanam, K.; Rao, L.V.G.; Sarkar, A.; Kumar, R.; Gairola, R.M.; Gohil, B.S.

    Geosat altimeter data for the period November 1986-October 1987 over the north Indian Ocean have been processed to retrieve wind speeds and significant wave heights. Smoothed Brown algorithm is used to retrieve wind speeds from back...

  13. Design study of a far-infrared free electron laser with a 20 MeV RF linear accelerator

    International Nuclear Information System (INIS)

    Nakata, S.; Tsukishima, C.; Hifumi, T.; Okuda, S.; Sato, S.; Yosojima, Y.

    1991-01-01

    A FEL in the far-infrared region has been designed using a low energy RF linear accelerator. First we estimate a small signal gain from spontaneous emission using the Madey's theorem. In the calculation following effects are included: an actual field distribution (using a measured magnetic field), beam envelope in the phase space through the undulator, energy spread, and electron beam mis-alignment to the undulator axis. We have developed a code which can simulate three dimensional processes of the electron interaction with multi-mode laser fields in the undulator. From this code we could obtain the time dependent bunching process of electrons and amplification of the laser field. During the calculation we assume an electron beam of 20 MeV, 100 mA with a pulse length of 3 μs, and an undulator of 28 periods, 6 cm periodic length and 2.5 kG peak field. The results from these calculations show that the small-signal gain over 40 % can be obtained, but mis-alignment of the beam severely degrades the gain. The results also show that the output power of several MW can be obtained under the above conditions. Considering the simulation results, a FEL beam line was constructed and the beam size at the undulator was measured. And electrons were focused enough for the FEL experiment. (author)

  14. Influence of laser design parameters on the hydrodynamics of microfusion plasmas

    International Nuclear Information System (INIS)

    Sanmartin, J.R.; Barrero, A.

    1976-01-01

    The quasineutral, oned ) 7mensional motion generated in a cold, infinite, uniform plasma of density n 0 , by the absorption, in a given plane, of a linear pulse of energy per unit time and area phi - phi 0 t/tau, 0 0 2 tau/phi 0 ) 2 /3. )etailed asymptotic results are obtained for both α > 1; the general behaviour of the solution for arbitrary α is discused. The analysis can be easily extended to the case of a plasma initially occuping a half-space, and throws light on the hydrodynamics of laser fusion plasmas. Approximate results existing in the literature for constant irradiation (phi) of a plasma are recovered under appropiate limiting processes. (author). )] [es

  15. Diode laser absorption spectroscopy for process control: Sensor system design methodology

    International Nuclear Information System (INIS)

    Berzins, L.V.; Anklam, T.M.; Chambers, F.; Galanti, S.; Haynam, C.A.; Worden, E.F.

    1995-03-01

    A laser absorption spectroscopy (LAS) system has been developed at Lawrence Livermore National Laboratory (LLNL) for process control. LAS has proven itself to be an accurate and reliable method to monitor both density and composition. In this paper the important features and components of an industrial LAS diagnostic are described. Application of this approach to vaporization processes requires careful selection of the species and transitions to be monitored The relative vapor pressure, hyperfine structure, isotopic frequency shifts, and electronic temperature all effect the selection of a particular transition. In this paper we describe the methodology for choosing the optimal transition or transitions. Coevaporation of a titanium-niobium alloy is used to illustrate the methodology. In a related paper, T.M. Anklam et al describe the application of this diagnostic to monitoring and controlling composition in a physical vapor deposition process of industrial interest

  16. Ultrafast gated intensifier design for laser fusion x-ray framing applications

    International Nuclear Information System (INIS)

    Price, R.H.; Wiedwald, J.D.; Kalibjian, R.; Thomas, S.W.; Cook, W.M.

    1983-01-01

    A major challenge for laser fusion is the study of the symmetry and the hydrodynamic stability of imploding fuel capsules. Streaked x-radiography, in one space and one time dimension, does not provide sufficient information. Two (spatial) dimensional frames of 10 to 100 ps duration are required with good image quality, minimum geometrical distortion (approximately 1%), dynamic range greater than 1000 and greater than 200 x 200 pixels. A gated transmission line imager (TLI) can meet these requirements with frame times between 30 and 100 ps. An instrument of this type is now being developed. Progress on this instrument including theory of operation, ultrafast pulse generation and propagation, component integration, and high resolution phosphor screen development are presented

  17. Design of Wear-Resistant Austenitic Steels for Selective Laser Melting

    Science.gov (United States)

    Lemke, J. N.; Casati, R.; Lecis, N.; Andrianopoli, C.; Varone, A.; Montanari, R.; Vedani, M.

    2018-03-01

    Type 316L stainless steel feedstock powder was modified by alloying with powders containing carbide/boride-forming elements to create improved wear-resistant austenitic alloys that can be readily processed by Selective Laser Melting. Fe-based alloys with high C, B, V, and Nb contents were thus produced, resulting in a microstructure that consisted of austenitic grains and a significant amount of hard carbides and borides. Heat treatments were performed to modify the carbide distribution and morphology. Optimal hard-phase spheroidization was achieved by annealing the proposed alloys at 1150 °C for 1 hour followed by water quenching. The total increase in hardness of samples containing 20 pct of C/B-rich alloy powder was of 82.7 pct while the wear resistance could be increased by a factor of 6.

  18. Laser-plasma harmonics with high-contrast pulses and designed prepulses

    International Nuclear Information System (INIS)

    Marjoribanks, R. S.; Zhao, L.; Budnik, F. W.; Kulcsar, G.; Vitcu, A.; Higaki, H.; Wagner, R.; Maksimchuk, A.; Umstadter, D.; Le Blanc, S. P.; Downer, M. C.

    1998-01-01

    One aspect of the complexity of mid- and high-harmonic generation in high-intensity laser-plasma interactions is that nonlinear hydrodynamics is virtually always folded together with the nonlinear optical conversion process. We have partly dissected this issue in picosecond and subpicosecond interactions with preformed plasma gradients, imaging and spectrally resolving low- and mid-order harmonics. We describe spatial breakup of the picosecond beam in preformed plasmas, concomitant broadening and breakup of the harmonic spectrum, presumably through self-phase modulation, together with data on the sensitivity of harmonics production efficiency to the gradient or extent of preformed plasma. Lastly, we show preliminary data of regular Stokes-like and anti-Stokes-like satellites to the harmonics, accompanied by modification of the forward-scattered beam

  19. Evaluation of the optical design of laser Thomson scattering diagnostics for high-temperature EAST tokamak and low-temperature MAP-II divertor simulator

    International Nuclear Information System (INIS)

    Kado, Shinichiro; Scotti, Filippo; Xi Xiaoqi; Zhao Junyu

    2009-01-01

    The optical design of the laser Thomson scattering (LTS) system for EAST tokamak is now on-going. Based on the Visible YAG laser TVTS system developed in the MAP-II (material and plasma) steady-state linear divertor/edge plasma simulator at the University of Tokyo, the required specification and the applicability of the VIS-YAG-TVTS system was evaluated in terms of the photon number to be collected by the fiber light-guide to a spectrometer and the reciprocal linear dispersion of the spectrometer. Then, the possible design of the optical system was proposed. (author)

  20. Enhanced direct-modulated bandwidth of 37 GHz by a multi-section laser with a coupled-cavity-injection-grating design

    DEFF Research Database (Denmark)

    Bach, L.; Kaiser, W.; Reithmaier, J.P.

    2003-01-01

    Using a new multi-section laser concept based on a coupled-cavity-injection-grating design, the material related intrinsic 3 dB modulation bandwidth can be enhanced up to 37 GHz for a 1.5 mm long device.......Using a new multi-section laser concept based on a coupled-cavity-injection-grating design, the material related intrinsic 3 dB modulation bandwidth can be enhanced up to 37 GHz for a 1.5 mm long device....

  1. Design and performance of large area monolithic electron guns for the Aurora KrF laser system

    International Nuclear Information System (INIS)

    Kang, M.; Rosocha, L.A.; Romero, V.O.; Van Haaften, F.W.; Brucker, J.P.

    1985-01-01

    Aurora is an inertial confinement fusion laser system using optical angular multiplexing and a chain of four cold cathode electron beam driven KrF laser amplifiers to produce 10 to 20 kJ of optical energy

  2. Development and design of up-to-date laser scanning two-photon microscope using in neuroscience

    Science.gov (United States)

    Doronin, Maxim; Popov, Alexander

    2017-02-01

    Today one of the main areas of application of two-photon microscopy is biology. This is due to the fact that this technique allows to obtain 3D images of tissues due to laser focus change, that is possible due to substantially greater penetration depth on the main wavelength into biological tissues. Self-developed microscopy system provides possibility to service it and modify the structure of microscope depending on highly specialized experimental design and scientific goals. This article may be regarded as a quick reference to laboratory staff who are wishing to develop their own microscopy system for self-service and modernization of the system and in order to save the lab budget.

  3. Ensemble Kalman filter assimilation of temperature and altimeter data with bias correction and application to seasonal prediction

    Directory of Open Access Journals (Sweden)

    C. L. Keppenne

    2005-01-01

    Full Text Available To compensate for a poorly known geoid, satellite altimeter data is usually analyzed in terms of anomalies from the time mean record. When such anomalies are assimilated into an ocean model, the bias between the climatologies of the model and data is problematic. An ensemble Kalman filter (EnKF is modified to account for the presence of a forecast-model bias and applied to the assimilation of TOPEX/Poseidon (T/P altimeter data. The online bias correction (OBC algorithm uses the same ensemble of model state vectors to estimate biased-error and unbiased-error covariance matrices. Covariance localization is used but the bias covariances have different localization scales from the unbiased-error covariances, thereby accounting for the fact that the bias in a global ocean model could have much larger spatial scales than the random error.The method is applied to a 27-layer version of the Poseidon global ocean general circulation model with about 30-million state variables. Experiments in which T/P altimeter anomalies are assimilated show that the OBC reduces the RMS observation minus forecast difference for sea-surface height (SSH over a similar EnKF run in which OBC is not used. Independent in situ temperature observations show that the temperature field is also improved. When the T/P data and in situ temperature data are assimilated in the same run and the configuration of the ensemble at the end of the run is used to initialize the ocean component of the GMAO coupled forecast model, seasonal SSH hindcasts made with the coupled model are generally better than those initialized with optimal interpolation of temperature observations without altimeter data. The analysis of the corresponding sea-surface temperature hindcasts is not as conclusive.

  4. Laser Program annual report 1987

    Energy Technology Data Exchange (ETDEWEB)

    O' Neal, E.M.; Murphy, P.W.; Canada, J.A.; Kirvel, R.D.; Peck, T.; Price, M.E.; Prono, J.K.; Reid, S.G.; Wallerstein, L.; Wright, T.W. (eds.)

    1989-07-01

    This report discusses the following topics: target design and experiments; target materials development; laboratory x-ray lasers; laser science and technology; high-average-power solid state lasers; and ICF applications studies.

  5. Laser Program annual report 1987

    International Nuclear Information System (INIS)

    O'Neal, E.M.; Murphy, P.W.; Canada, J.A.; Kirvel, R.D.; Peck, T.; Price, M.E.; Prono, J.K.; Reid, S.G.; Wallerstein, L.; Wright, T.W.

    1989-07-01

    This report discusses the following topics: target design and experiments; target materials development; laboratory x-ray lasers; laser science and technology; high-average-power solid state lasers; and ICF applications studies

  6. Model-Aided Altimeter-Based Water Level Forecasting System in Mekong River

    Science.gov (United States)

    Chang, C. H.; Lee, H.; Hossain, F.; Okeowo, M. A.; Basnayake, S. B.; Jayasinghe, S.; Saah, D. S.; Anderson, E.; Hwang, E.

    2017-12-01

    Mekong River, one of the massive river systems in the world, has drainage area of about 795,000 km2 covering six countries. People living in its drainage area highly rely on resources given by the river in terms of agriculture, fishery, and hydropower. Monitoring and forecasting the water level in a timely manner, is urgently needed over the Mekong River. Recently, using TOPEX/Poseidon (T/P) altimetry water level measurements in India, Biancamaria et al. [2011] has demonstrated the capability of an altimeter-based flood forecasting system in Bangladesh, with RMSE from 0.6 - 0.8 m for lead times up to 5 days on 10-day basis due to T/P's repeat period. Hossain et al. [2013] further established a daily water level forecasting system in Bangladesh using observations from Jason-2 in India and HEC-RAS hydraulic model, with RMSE from 0.5 - 1.5 m and an underestimating mean bias of 0.25 - 1.25 m. However, such daily forecasting system relies on a collection of Jason-2 virtual stations (VSs) to ensure frequent sampling and data availability. Since the Mekong River is a meridional river with few number of VSs, the direct application of this system to the Mekong River becomes challenging. To address this problem, we propose a model-aided altimeter-based forecasting system. The discharge output by Variable Infiltration Capacity hydrologic model is used to reconstruct a daily water level product at upstream Jason-2 VSs based on the discharge-to-level rating curve. The reconstructed daily water level is then used to perform regression analysis with downstream in-situ water level to build regression models, which are used to forecast a daily water level. In the middle reach of the Mekong River from Nakhon Phanom to Kratie, a 3-day lead time forecasting can reach RMSE about 0.7 - 1.3 m with correlation coefficient around 0.95. For the lower reach of the Mekong River, the water flow becomes more complicated due to the reversal flow between the Tonle Sap Lake and the Mekong River

  7. Nonlocal heat transport and improved target design for x-ray heating studies at x-ray free electron lasers

    Science.gov (United States)

    Hoidn, Oliver; Seidler, Gerald T.

    2018-01-01

    The extremely high-power densities and short durations of single pulses of x-ray free electron lasers (XFELs) have opened new opportunities in atomic physics, where complex excitation-relaxation chains allow for high ionization states in atomic and molecular systems, and in dense plasma physics, where XFEL heating of solid-density targets can create unique dense states of matter having temperatures on the order of the Fermi energy. We focus here on the latter phenomena, with special emphasis on the problem of optimum target design to achieve high x-ray heating into the warm dense matter (WDM) state. We report fully three-dimensional simulations of the incident x-ray pulse and the resulting multielectron relaxation cascade to model the spatial energy density deposition in multicomponent targets, with particular focus on the effects of nonlocal heat transport due to the motion of high energy photoelectrons and Auger electrons. We find that nanoscale high-Z /low-Z multicomponent targets can give much improved energy density deposition in lower-Z materials, with enhancements reaching a factor of 100. This has three important benefits. First, it greatly enlarges the thermodynamic parameter space in XFEL x-ray heating studies of lower-Z materials. Second, it allows the use of higher probe photon energies, enabling higher-information content x-ray diffraction (XRD) measurements such as in two-color XFEL operations. Third, while this is merely one step toward optimization of x-ray heating target design, the demonstration of the importance of nonlocal heat transport establishes important common ground between XFEL-based x-ray heating studies and more traditional laser plasma methods.

  8. Evaluation and adjustment of altimeter measurement and numerical hindcast in wave height trend estimation in China's coastal seas

    Science.gov (United States)

    Li, Shuiqing; Guan, Shoude; Hou, Yijun; Liu, Yahao; Bi, Fan

    2018-05-01

    A long-term trend of significant wave height (SWH) in China's coastal seas was examined based on three datasets derived from satellite measurements and numerical hindcasts. One set of altimeter data were obtained from the GlobWave, while the other two datasets of numerical hindcasts were obtained from the third-generation wind wave model, WAVEWATCH III, forced by wind fields from the Cross-Calibrated Multi-Platform (CCMP) and NCEP's Climate Forecast System Reanalysis (CFSR). The mean and extreme wave trends were estimated for the period 1992-2010 with respect to the annual mean and the 99th-percentile values of SWH, respectively. The altimeter wave trend estimates feature considerable uncertainties owing to the sparse sampling rate. Furthermore, the extreme wave trend tends to be overestimated because of the increasing sampling rate over time. Numerical wave trends strongly depend on the quality of the wind fields, as the CCMP waves significantly overestimate the wave trend, whereas the CFSR waves tend to underestimate the trend. Corresponding adjustments were applied which effectively improved the trend estimates from the altimeter and numerical data. The adjusted results show generally increasing mean wave trends, while the extreme wave trends are more spatially-varied, from decreasing trends prevailing in the South China Sea to significant increasing trends mainly in the East China Sea.

  9. Study of the Penetration Bias of ENVISAT Altimeter Observations over Antarctica in Comparison to ICESat Observations

    Directory of Open Access Journals (Sweden)

    Aurélie Michel

    2014-09-01

    Full Text Available The aim of this article is to characterize the penetration bias of the ENVIronmental SATellite (ENVISAT radar altimeter over the Antarctic ice sheet through comparison with the more accurate measurements of the Ice, Cloud and land Elevation Satellite (ICESat altimeter at crossover points. We studied the difference between ENVISAT and ICESat fluctuations over six years. We observed the same patterns between the leading edge width and the elevation difference. Both parameters are linked, and the major bias is due to the lengthening of the leading edge width due to the radar penetration. We show that the elevation difference between both altimeters and the leading edge width are linearly well-linked with a 0.8 Pearson correlation coefficient, whereas the slope effect over the coasts is difficult to analyze. When we analyze each crossover point temporal evolution locally, the linear correlation between the leading edge width and the elevation difference is between −0.6 and −1. Fitting a linear model between them, we find a reliability index greater than 0.7 for the Antarctic Plateau and Dronning Maud Land, which confirms that the penetration effect has a linear influence on the retrieved height. Moreover, we present results from SARAL/AltiKa (launched in February 2013 that confirm SARAL/AltiKa accuracy and the promising information it will provide.

  10. Design of laser-driven SiO2-YAG:Ce composite thick film: Facile synthesis, robust thermal performance, and application in solid-state laser lighting

    Science.gov (United States)

    Xu, Jian; Liu, Bingguo; Liu, Zhiwen; Gong, Yuxuan; Hu, Baofu; Wang, Jian; Li, Hui; Wang, Xinliang; Du, Baoli

    2018-01-01

    In recent times, there have been rapid advances in the solid-state laser lighting technology. Due to the large amounts of heat accumulated from the high flux laser radiation, color conversion materials used in solid-state laser lighting devices should possess high durability, high thermal conductivity, and low thermal quenching. The aim of this study is to develop a thermally robust SiO2-YAG:Ce composite thick film (CTF) for high-power solid-state laser lighting applications. Commercial colloidal silica which was used as the source of SiO2, played the roles of an adhesive, a filler, and a protecting agent. Compared to the YAG:Ce powder, the CTF exhibits remarkable thermal stability (11.3% intensity drop at 200 °C) and durability (4.5% intensity drop after 1000 h, at 85 °C and 85% humidity). Furthermore, the effects of the substrate material and the thickness of the CTF on the laser lighting performance were investigated in terms of their thermal quenching and luminescence saturation behaviors, respectively. The CTF with a thickness of 50 μm on a sapphire substrate does not show luminescence saturation, despite a high-power density of incident radiation i.e. 20 W/mm2. These results demonstrate the potential applicability of the CTF in solid-state laser lighting devices.

  11. Design and Fabrication of 850 and 980 nm Vertical Cavity Surface Emitting Laser

    National Research Council Canada - National Science Library

    Das, N

    2004-01-01

    .... VCSELs on GaAs substrates were grown by the molecular beam epitaxy technique. In this report we present detailed procedures to design and fabricate 850-nm top-emitting and 980-nm bottom-emitting VCSELs...

  12. Technological laser application

    International Nuclear Information System (INIS)

    Shia, D.O.; Kollen, R.; Rods, U.

    1980-01-01

    Problems of the technological applications of lasers are stated in the popular form. Main requirements to a technological laser as well as problems arising in designing any system using lasers have been considered. Areas of the laser applications are described generally: laser treatment of materials, thermal treatment, welding, broach and drilling of holes, scribing, microtreatment and adjustment of resistors, material cutting, investigations into controlled thermonuclear fussion

  13. Design optimization for 25 Gbit/s DML InGaAlAs/InGaAsP/InP SL-MQW laser diode incorporating temperature effect

    Science.gov (United States)

    Ke, Cheng; Li, Xun; Xi, Yanping; Yu, Yang

    2017-11-01

    In this paper, a detailed carrier dynamics model for quantum well lasers is used to study the modulation bandwidth of the directly modulated strained-layer multiple quantum well (SL-MQW) laser. The active region of the directly modulated laser (DML) is optimized in terms of the number of QWs and barrier height. To compromise the device dynamic performance at different operating temperatures, we present an overall optimized design for a 25 Gbps DML under an ambient temperature ranging from 25 to 85°C. To further enhance the modulation bandwidth, we have also proposed a mixed QWs design that increases the 3 dB bandwidth by almost 44% compared to the one without undergoing optimization. The experimental results show that the 3 dB bandwidth of the optimized DML can reach 19 GHz. A clear eye diagram with a bit rate of 25 Gbps was observed at 25°C.

  14. Influence of lasers with non-white frequency noise on the design of coherent optical links

    DEFF Research Database (Denmark)

    Kakkar, Aditya; Navarro, Jaime Rodrigo; Schatz, Richard

    2017-01-01

    We experimentally demonstrate for a 28 Gbaud 64-QAM metro link that the LO frequency noise causes timing impairment. Results show the existence of LO frequency noise spectrum regimes where different design criteria apply.......We experimentally demonstrate for a 28 Gbaud 64-QAM metro link that the LO frequency noise causes timing impairment. Results show the existence of LO frequency noise spectrum regimes where different design criteria apply....

  15. Conceptual design of a 20 Tesla pulsed solenoid for a laser solenoid fusion reactor

    International Nuclear Information System (INIS)

    Nolan, J.J.; Averill, R.J.

    1977-01-01

    Design considerations are described for a strip wound solenoid which is pulsed to 20 tesla while immersed in a 20 tesla bias field so as to achieve within the bore of the pulsed solenoid at net field sequence starting at 20 tesla and going first down to zero, then up to 40 tesla, and finally back to 20 tesla in a period of about 5 x 10 -3 seconds. The important parameters of the solenoid, e.g., aperture, build, turns, stored and dissipated energy, field intensity and powering circuit, are given. A numerical example for a specific design is presented. Mechanical stresses in the solenoid and the subsequent choice of materials for coil construction are discussed. Although several possible design difficulties are not discussed in this preliminary report of a conceptual magnet design, such as uniformity of field, long-term stability of insulation under neutron bombardment and choice of structural materials of appropriate tensile strength and elasticity to withstand magnetic forces developed, these questions are addressed in detail in the complete design report and in part in reference one. Furthermore, the authors feel that the problems encountered in this conceptual design are surmountable and are not a hindrance to the construction of such a magnet system

  16. Osseointegration of three-dimensional designed titanium implants manufactured by selective laser melting.

    Science.gov (United States)

    Shaoki, Algabri; Xu, Jia-Yun; Sun, Haipeng; Chen, Xian-Shuai; Ouyang, Jianglin; Zhuang, Xiu-Mei; Deng, Fei-Long

    2016-10-27

    The selective laser melting (SLM) technique is a recent additive manufacturing (AM) technique. Several studies have reported success in the SLM-based production of biocompatible orthopaedic implants and three-dimensional bone defect constructs. In this study, we evaluated the surface properties and biocompatibility of an SLM titanium implant in vitro and compared them with those of a machined (MA) titanium control surface. In addition, we evaluated the osseointegration capability of the SLM implants in vivo and compared it with those of MA and Nobel-speedy (Nobel-S) implants. SLM microtopographical surface analysis revealed porous and high roughness with varied geometry compared with a smooth surface in MA Ti samples but with similar favourable wettability. Osteoblast proliferation and alkaline phosphatase activity were significantly enhanced on the SLM surface. Histological analysis of the bone-implant contact ratio revealed no significant difference among SLM, MA, and Nobel-S implants. Micro-CT assessment indicated that there was no significant difference in bone volume fraction around the implant among SLM implants and other types of surface modification implants. The removal torque value measurement of SLM implants was significantly lower that of than Nobel-S implants P manufacturing technique.

  17. An integrated approach of topology optimized design and selective laser melting process for titanium implants materials.

    Science.gov (United States)

    Xiao, Dongming; Yang, Yongqiang; Su, Xubin; Wang, Di; Sun, Jianfeng

    2013-01-01

    The load-bearing bone implants materials should have sufficient stiffness and large porosity, which are interacted since larger porosity causes lower mechanical properties. This paper is to seek the maximum stiffness architecture with the constraint of specific volume fraction by topology optimization approach, that is, maximum porosity can be achieved with predefine stiffness properties. The effective elastic modulus of conventional cubic and topology optimized scaffolds were calculated using finite element analysis (FEA) method; also, some specimens with different porosities of 41.1%, 50.3%, 60.2% and 70.7% respectively were fabricated by Selective Laser Melting (SLM) process and were tested by compression test. Results showed that the computational effective elastic modulus of optimized scaffolds was approximately 13% higher than cubic scaffolds, the experimental stiffness values were reduced by 76% than the computational ones. The combination of topology optimization approach and SLM process would be available for development of titanium implants materials in consideration of both porosity and mechanical stiffness.

  18. Laser application of heat pipe technology in energy related programs

    International Nuclear Information System (INIS)

    Carbone, R.J.

    1975-01-01

    The design and operating parameters for a heat pipe laser utilizing metal vapors are proposed. The laser would be applied to laser induced fusion, laser induced chemistry, laser isotope separation, and power transport using optical beams. (U.S.)

  19. Global ocean tides through assimilation of oceanographic and altimeter satellite data in a hydrodynamic model

    Science.gov (United States)

    Leprovost, Christian; Mazzega, P.; Vincent, P.

    1991-01-01

    Ocean tides must be considered in many scientific disciplines: astronomy, oceanography, geodesy, geophysics, meteorology, and space technologies. Progress in each of these disciplines leads to the need for greater knowledge and more precise predictions of the ocean tide contribution. This is particularly true of satellite altimetry. On one side, the present and future satellite altimetry missions provide and will supply new data that will contribute to the improvement of the present ocean tide solutions. On the other side, tidal corrections included in the Geophysical Data Records must be determined with the maximum possible accuracy. The valuable results obtained with satellite altimeter data thus far have not been penalized by the insufficiencies of the present ocean tide predictions included in the geophysical data records (GDR's) because the oceanic processes investigated have shorter wavelengths than the error field of the tidal predictions, so that the residual errors of the tidal corrections are absorbed in the empirical tilt and bias corrections of the satellite orbit. For future applications to large-scale oceanic phenomena, however, it will no longer be possible to ignore these insufficiencies.

  20. Modal recovery of sea-level variability in the South China Sea using merged altimeter data

    Science.gov (United States)

    Jiang, Haoyu; Chen, Ge

    2015-09-01

    Using 20 years (1993-2012) of merged data recorded by contemporary multi-altimeter missions, a variety of sea-level variability modes are recovered in the South China Sea employing three-dimensional harmonic extraction. In terms of the long-term variation, the South China Sea is estimated to have a rising sea-level linear trend of 5.39 mm/a over these 20 years. Among the modes extracted, the seven most statistically significant periodic or quasi-periodic modes are identified as principal modes. The geographical distributions of the magnitudes and phases of the modes are displayed. In terms of intraannual and annual regimes, two principal modes with strict semiannual and annual periods are found, with the annual variability having the largest amplitudes among the seven modes. For interannual and decadal regimes, five principal modes at approximately 18, 21, 23, 28, and 112 months are found with the most mode-active region being to the east of Vietnam. For the phase distributions, a series of amphidromes are observed as twins, termed "amphidrome twins", comprising rotating dipole systems. The stability of periodic modes is investigated employing joint spatiotemporal analysis of latitude/longitude sections. Results show that all periodic modes are robust, revealing the richness and complexity of sea-level modes in the South China Sea.