Free-space QKD system hacking by wavelength control using an external laser.

Science.gov (United States)

Lee, Min Soo; Woo, Min Ki; Jung, Jisung; Kim, Yong-Su; Han, Sang-Wook; Moon, Sung

2017-05-15

We develop a way to hack free-space quantum key distribution (QKD) systems by changing the wavelength of the quantum signal laser using an external laser. Most free-space QKD systems use four distinct lasers for each polarization, thereby making the characteristics of each laser indistinguishable. We also discover a side-channel that can distinguish the lasers by using an external laser. Our hacking scheme identifies the lasers by automatically applying the external laser to each signal laser at different intensities and detecting the wavelength variation according to the amount of incident external laser power. We conduct a proof-of-principle experiment to verify the proposed hacking structure and confirm that the wavelength varies by several gigahertzes to several nanometers, depending on the intensity of the external laser. The risk of hacking is successfully proven through the experimental results. Methods for prevention are also suggested.

Post-Newtonian equations of motion for LEO debris objects and space-based acquisition, pointing and tracking laser systems

Science.gov (United States)

Gambi, J. M.; García del Pino, M. L.; Gschwindl, J.; Weinmüller, E. B.

2017-12-01

This paper deals with the problem of throwing middle-sized low Earth orbit debris objects into the atmosphere via laser ablation. The post-Newtonian equations here provided allow (hypothetical) space-based acquisition, pointing and tracking systems endowed with very narrow laser beams to reach the pointing accuracy presently prescribed. In fact, whatever the orbital elements of these objects may be, these equations will allow the operators to account for the corrections needed to balance the deviations of the line of sight directions due to the curvature of the paths the laser beams are to travel along. To minimize the respective corrections, the systems will have to perform initial positioning manoeuvres, and the shooting point-ahead angles will have to be adapted in real time. The enclosed numerical experiments suggest that neglecting these measures will cause fatal errors, due to differences in the actual locations of the objects comparable to their size.

A 12 GHz wavelength spacing multi-wavelength laser source for wireless communication systems

Science.gov (United States)

Peng, P. C.; Shiu, R. K.; Bitew, M. A.; Chang, T. L.; Lai, C. H.; Junior, J. I.

2017-08-01

This paper presents a multi-wavelength laser source with 12 GHz wavelength spacing based on a single distributed feedback laser. A light wave generated from the distributed feedback laser is fed into a frequency shifter loop consisting of 50:50 coupler, dual-parallel Mach-Zehnder modulator, optical amplifier, optical filter, and polarization controller. The frequency of the input wavelength is shifted and then re-injected into the frequency shifter loop. By re-injecting the shifted wavelengths multiple times, we have generated 84 optical carriers with 12 GHz wavelength spacing and stable output power. For each channel, two wavelengths are modulated by a wireless data using the phase modulator and transmitted through a 25 km single mode fiber. In contrast to previously developed schemes, the proposed laser source does not incur DC bias drift problem. Moreover, it is a good candidate for radio-over-fiber systems to support multiple users using a single distributed feedback laser.

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.

Welding technology transfer task/laser based weld joint tracking system for compressor girth welds

Science.gov (United States)

Looney, Alan

1991-01-01

Sensors to control and monitor welding operations are currently being developed at Marshall Space Flight Center. The laser based weld bead profiler/torch rotation sensor was modified to provide a weld joint tracking system for compressor girth welds. The tracking system features a precision laser based vision sensor, automated two-axis machine motion, and an industrial PC controller. The system benefits are elimination of weld repairs caused by joint tracking errors which reduces manufacturing costs and increases production output, simplification of tooling, and free costly manufacturing floor space.

Fiber-Based, Trace-Gas, Laser Transmitter Technology Development for Space

Science.gov (United States)

Stephen, Mark; Yu, Anthony; Chen, Jeffrey; Nicholson, Jeffrey; Engin, Doruk; Mathason, Brian; Wu, Stewart; Allan, Graham; Hasselbrack, William; Gonzalez, Brayler;

Development of laser weld monitoring system for PWR space grid

International Nuclear Information System (INIS)

Chung, Chin Man; Kim, Cheol Jung; Kim, Min Suk

1998-06-01

The laser welding monitoring system was developed to inspect PWR space grid welding for KNFC. The demands for this optical monitoring system were applied to Q.C. and process control in space grid welding. The thermal radiation signal from weld pool can be get the variation of weld pool size. The weld pool size and depth are verified by analyzed wavelength signals from weld pool. Applied this monitoring system in space grid weld, improved the weld productivity. (author). 4 refs., 5 tabs., 31 figs

REFINED MODEL OF THE OPTICAL SYSTEM FOR SPACE MINI-VEHICLES WITH LASER PROPULSION

Directory of Open Access Journals (Sweden)

M. S. Egorov

2015-09-01

Full Text Available Simulation results for on-board optical system of a space mini-vehicle with laser propulsion are presented. This system gives the possibility for receiving theremote laser radiation power independently of a system telescope mutual orientation to the vehicle orbiting direction. The on-board optical system is designed with the use of such optical elements as optical hinges and turrets. The system incorporates the optical switch that is a special optical system adapting optically both receiving telescope and laser propulsion engines. Modeling and numerical simulation of the system have been performed with the use of ZEMAX software (Radiant Ltd. The object matter of calculations lied in size definition of system optical elements, requirements to accuracy of their manufacturing and reciprocal adjusting to achieve an efficient radiation energy delivery to laser propulsion engine. Calculations have been performed with account to the limitations on the mini-vehicle mass, its overall dimensions, and radiation threshold density of the optical elements utilized. The requirements to the laser beam quality at the entrance aperture of laser propulsion engine have been considered too. State-of-the-art optical technologies make it possible to manufacture space reflectors made of CO-115M glassceramics with weight-reducing coefficient of 0.72 and the radiation threshold of 5 J/cm2 for the radiation with a 1.064 microns wavelength at 10-20 ns pulse duration. The optimal diameter of a receiving telescope primary mirror has been 0.5 m when a coordinated transmitting telescope diameter is equal to 1 m. This provides the reception of at least 84% of laser energy. The main losses of radiation energy are caused by improper installation of receiving telescope mirrors and by in-process errors arising at manufacturing the telescope mirrors with a parabolic surface. It is shown that requirements to the in-process admissible errors for the on-board optical system elements

Free-space laser communication technologies; Proceedings of the Meeting, Los Angeles, CA, Jan. 11, 12, 1988

Science.gov (United States)

Koepf, Gerhard A.; Begley, David L.

1988-01-01

The present conference discusses topics in free-space laser communications, laser link characteristics, satellite laser communication systems, optoelectronic components for laser communications, and space laser subsystem technologies. Attention is given to Space Station-based deep-space communication experiments, the application of intersatellite links to operational satellite systems, high-power 0.87 micron channel substrate planar lasers for spaceborne communications, a ground experiment using a CO2 laser transceiver for free-space communications, studies of laser ranging to the TOPEX satellite, diffraction-limited tracking for space communications, and the compact implementation of a real-time, acoustooptic SAR processor.

GaN-Based Laser Wireless Power Transfer System

Directory of Open Access Journals (Sweden)

Carlo De Santi

2018-01-01

Full Text Available The aim of this work is to present a potential application of gallium nitride-based optoelectronic devices. By using a laser diode and a photodetector, we designed and demonstrated a free-space compact and lightweight wireless power transfer system, whose efficiency is limited by the efficiency of the receiver. We analyzed the effect of the electrical load, temperature, partial absorption and optical excitation distribution on the efficiency, by identifying heating and band-filling as the most impactful processes. By comparing the final demonstrator with a commercial RF-based Qi system, we conclude that the efficiency is still low at close range, but is promising in medium to long range applications. Efficiency may not be a limiting factor, since this concept can enable entirely new possibilities and designs, especially relevant for space applications.

Self-Raman Nd:YVO4 Laser and Electro-Optic Technology for Space-Based Sodium Lidar Instrument

Science.gov (United States)

Krainak, Michael A.; Yu, Anthony W.; Janches, Diego; Jones, Sarah L.; Blagojevic, Branimir; Chen, Jeffrey

2014-01-01

We are developing a laser and electro-optic technology to remotely measure Sodium (Na) by adapting existing lidar technology with space flight heritage. The developed instrumentation will serve as the core for the planning of an Heliophysics mission targeted to study the composition and dynamics of Earth's mesosphere based on a spaceborne lidar that will measure the mesospheric Na layer. We present performance results from our diode-pumped tunable Q-switched self-Raman c-cut Nd:YVO4 laser with intra-cavity frequency doubling that produces multi-watt 589 nm wavelength output. The c-cut Nd:YVO4 laser has a fundamental wavelength that is tunable from 1063-1067 nanometers. A CW (Continuous Wave) External Cavity diode laser is used as a injection seeder to provide single-frequency grating tunable output around 1066 nanometers. The injection-seeded self-Raman shifted Nd:VO4 laser is tuned across the sodium vapor D2 line at 589 nanometers. We will review technologies that provide strong leverage for the sodium lidar laser system with strong heritage from the Ice Cloud and Land Elevation Satellite-2 (ICESat-2) Advanced Topographic Laser Altimeter System (ATLAS). These include a space-qualified frequency-doubled 9 watts-at-532-nanometer wavelength Nd:YVO4 laser, a tandem interference filter temperature-stabilized fused-silica-etalon receiver and high-bandwidth photon-counting detectors.

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.

Comparing Laser Interferometry and Atom Interferometry Approaches to Space-Based Gravitational-Wave Measurement

Science.gov (United States)

Baker, John; Thorpe, Ira

2012-01-01

Thoroughly studied classic space-based gravitational-wave missions concepts such as the Laser Interferometer Space Antenna (LISA) are based on laser-interferometry techniques. Ongoing developments in atom-interferometry techniques have spurred recently proposed alternative mission concepts. These different approaches can be understood on a common footing. We present an comparative analysis of how each type of instrument responds to some of the noise sources which may limiting gravitational-wave mission concepts. Sensitivity to laser frequency instability is essentially the same for either approach. Spacecraft acceleration reference stability sensitivities are different, allowing smaller spacecraft separations in the atom interferometry approach, but acceleration noise requirements are nonetheless similar. Each approach has distinct additional measurement noise issues.

Adaptive Laser Sintering System for In-space Printed Electronics, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The goal of this project is to enhance the Optomec Aerosol Jet(R) technology for additive manufacturing by introduction of an Adaptive Laser Sintering System (ALSS)...

On-Chip Laser-Power Delivery System for Dielectric Laser Accelerators

Science.gov (United States)

Hughes, Tyler W.; Tan, Si; Zhao, Zhexin; Sapra, Neil V.; Leedle, Kenneth J.; Deng, Huiyang; Miao, Yu; Black, Dylan S.; Solgaard, Olav; Harris, James S.; Vuckovic, Jelena; Byer, Robert L.; Fan, Shanhui; England, R. Joel; Lee, Yun Jo; Qi, Minghao

2018-05-01

We propose an on-chip optical-power delivery system for dielectric laser accelerators based on a fractal "tree-network" dielectric waveguide geometry. This system replaces experimentally demanding free-space manipulations of the driving laser beam with chip-integrated techniques based on precise nanofabrication, enabling access to orders-of-magnitude increases in the interaction length and total energy gain for these miniature accelerators. Based on computational modeling, in the relativistic regime, our laser delivery system is estimated to provide 21 keV of energy gain over an acceleration length of 192 μ m with a single laser input, corresponding to a 108-MV/m acceleration gradient. The system may achieve 1 MeV of energy gain over a distance of less than 1 cm by sequentially illuminating 49 identical structures. These findings are verified by detailed numerical simulation and modeling of the subcomponents, and we provide a discussion of the main constraints, challenges, and relevant parameters with regard to on-chip laser coupling for dielectric laser accelerators.

Free electron lasers for transmission of energy in space

Science.gov (United States)

Segall, S. B.; Hiddleston, H. R.; Catella, G. C.

1981-01-01

A one-dimensional resonant-particle model of a free electron laser (FEL) is used to calculate laser gain and conversion efficiency of electron energy to photon energy. The optical beam profile for a resonant optical cavity is included in the model as an axial variation of laser intensity. The electron beam profile is matched to the optical beam profile and modeled as an axial variation of current density. Effective energy spread due to beam emittance is included. Accelerators appropriate for a space-based FEL oscillator are reviewed. Constraints on the concentric optical resonator and on systems required for space operation are described. An example is given of a space-based FEL that would produce 1.7 MW of average output power at 0.5 micrometer wavelength with over 50% conversion efficiency of electrical energy to laser energy. It would utilize a 10 m-long amplifier centered in a 200 m-long optical cavity. A 3-amp, 65 meV electrostatic accelerator would provide the electron beam and recover the beam after it passes through the amplifier. Three to five shuttle flights would be needed to place the laser in orbit.

Intensity position modulation for free-space laser communication system

Science.gov (United States)

Jangjoo, Alireza; Faghihi, F.

2004-12-01

In this research a novel modulation technique for free-space laser communication system called Intensity Position Modulation (IPM) is carried out. According to TEM00 mode of a laser beam and by linear fitting on the Gaussian function as an approximation, the variation of linear part on the reverse biased pn photodiode produced alternating currents which contain the information. Here, no characteristic property of the beam as intensity or frequency is changed and only the beam position moves laterally. We demonstrated that in this method no bandwidth is required, so it is possible to reduce the background radiation noise by narrowband filtering of the carrier. The fidelity of the analog voice communication system which is made upon the IPM is satisfactory and we are able to transmit the audio signals up to 1Km.

Initial alignment method for free space optics laser beam

Science.gov (United States)

Shimada, Yuta; Tashiro, Yuki; Izumi, Kiyotaka; Yoshida, Koichi; Tsujimura, Takeshi

2016-08-01

The authors have newly proposed and constructed an active free space optics transmission system. It is equipped with a motor driven laser emitting mechanism and positioning photodiodes, and it transmits a collimated thin laser beam and accurately steers the laser beam direction. It is necessary to introduce the laser beam within sensible range of the receiver in advance of laser beam tracking control. This paper studies an estimation method of laser reaching point for initial laser beam alignment. Distributed photodiodes detect laser luminescence at respective position, and the optical axis of laser beam is analytically presumed based on the Gaussian beam optics. Computer simulation evaluates the accuracy of the proposed estimation methods, and results disclose that the methods help us to guide the laser beam to a distant receiver.

Laser Safety and Hazard Analysis for the Trailer (B70) Based AURA Laser System

International Nuclear Information System (INIS)

AUGUSTONI, ARNOLD L.

2003-01-01

A laser safety and hazard analysis was performed for the AURA laser system based on the 2000 version of the American National Standards Institute's (ANSI) Standard Z136.1, for ''Safe Use of Lasers'' and the 2000 version of the ANSI Standard Z136.6, for ''Safe Use of Lasers Outdoors''. The trailer based AURA laser system is a mobile platform, which is used to perform laser interaction experiments and tests at various national test sites. The trailer (B70) based AURA laser system is generally operated on the United State Air Force Starfire Optical Range (SOR) at Kirtland Air Force Base (KAFB), New Mexico. The laser is used to perform laser interaction testing inside the laser trailer as well as outside the trailer at target sites located at various distances from the exit telescope. In order to protect personnel, who work inside the Nominal Hazard Zone (NHZ), from hazardous laser emission exposures it was necessary to determine the Maximum Permissible Exposure (MPE) for each laser wavelength (wavelength bands) and calculate the appropriate minimum Optical Density (OD min ) of the laser safety eyewear used by authorized personnel and the Nominal Ocular Hazard Distance (NOHD) to protect unauthorized personnel who may have violated the boundaries of the control area and enter into the laser's NHZ

Commercialization plan laser-based decoating systems

International Nuclear Information System (INIS)

Freiwald, J.; Freiwald, D.A.

1998-01-01

F2 Associates Inc. (F2) is a small, high-technology firm focused on developing and commercializing environmentally friendly laser ablation systems for industrial-rate removal of surface coatings from metals, concrete, and delicate substrates such as composites. F2 has a contract with the US Department of Energy Federal Energy Technology Center (FETC) to develop and test a laser-based technology for removing contaminated paint and other contaminants from concrete and metal surfaces. Task 4.1 in Phase 2 of the Statement of Work for this DOE contract requires that F2 ''document its plans for commercializing and marketing the stationary laser ablation system. This document shall include a discussion of prospects for commercial customers and partners and may require periodic update to reflect changing strategy. This document shall be submitted to the DOE for review.'' This report is being prepared and submitted in fulfillment of that requirement. This report describes the laser-based technology for cleaning and coatings removal, the types of laser-based systems that have been developed by F2 based on this technology, and the various markets that are emerging for this technology. F2's commercialization and marketing plans are described, including how F2's organization is structured to meet the needs of technology commercialization, F2's strategy and marketing approach, and the necessary steps to receive certification for removing paint from aircraft and DOE certification for D and D applications. The future use of the equipment built for the DOE contract is also discussed

Progress on High-Energy 2-micron Solid State Laser for NASA Space-Based Wind and Carbon Dioxide Measurements

Science.gov (United States)

Singh, Upendra N.

2011-01-01

Sustained research efforts at NASA Langley Research Center during last fifteen years have resulted in significant advancement of a 2-micron diode-pumped, solid-state laser transmitter for wind and carbon dioxide measurements from ground, air and space-borne platforms. Solid-state 2-micron laser is a key subsystem for a coherent Doppler lidar that measures the horizontal and vertical wind velocities with high precision and resolution. The same laser, after a few modifications, can also be used in a Differential Absorption Lidar system for measuring atmospheric CO2 concentration profiles. Researchers at NASA Langley Research Center have developed a compact, flight capable, high energy, injection seeded, 2-micron laser transmitter for ground and airborne wind and carbon dioxide measurements. It is capable of producing 250 mJ at 10 Hz by an oscillator and one amplifier. This compact laser transmitter was integrated into a mobile trailer based coherent Doppler wind and CO2 DIAL system and was deployed during field measurement campaigns. This paper will give an overview of 2-micron solid-state laser technology development and discuss results from recent ground-based field measurements.

Acousto-optic pointing and tracking systems for free-space laser communications

Science.gov (United States)

Nikulin, V.; Khandekar, R.; Sofka, J.; Tartakovsky, G.

2005-08-01

Implementation of long-range laser communication systems holds great promise for high-bandwidth applications. They are viewed as a technology that in the nearest future will handle most of the "last mile" communication traffic for the individual subscribers, corporate offices, military, and possibly deep space probes. Indeed, lasers allow for concentration of energy within tightly focused beams and narrow spectral interval, thus offering high throughput, information security, weight and size of components and power requirements that could not be matched by RF systems. However, the advantages of optical communication systems come in the same package with several major challenges. In particular, high data rates should be complemented by high-precision wide-bandwidth position control of a laser beam. In many applications the ability to maintain a link is affected by the complex maneuvers performed by mobile communication platforms, resident vibrations, and atmospheric effects. The search for the most effective and reliable way to shape and steer the laser beam is an on-going effort. This paper is focused on the application of acousto-optic technology as an alternative to electro-mechanical devices. With realization that an acousto-optic Bragg cell is only a component of the entire communication system, which should perform complex tasks of acquisition, pointing, and tracking of the remote terminal, we present an attempt to consider this problem from the "systems" point of view.

Fiber Laser Component Testing for Space Qualification Protocol Development

Science.gov (United States)

Falvey, S.; Buelow, M.; Nelson, B.; Starcher, Y.; Thienel, L.; Rhodes, C.; Tull, Jackson; Drape, T.; Westfall, C.

A test protocol for the space qualifying of Ytterbium-doped diode-pumped fiber laser (DPFL) components was developed under the Bright Light effort, sponsored by AFRL/VSE. A literature search was performed and summarized in an AMOS 2005 conference paper that formed the building blocks for the development of the test protocol. The test protocol was developed from the experience of the Bright Light team, the information in the literature search, and the results of a study of the Telcordia standards. Based on this protocol developed, test procedures and acceptance criteria for a series of vibration, thermal/vacuum, and radiation exposure tests were developed for selected fiber laser components. Northrop Grumman led the effort in vibration and thermal testing of these components at the Aerospace Engineering Facility on Kirtland Air Force Base, NM. The results of the tests conducted have been evaluated. This paper discusses the vibration and thermal testing that was executed to validate the test protocol. The lessons learned will aid in future assessments and definition of space qualification protocols. Components representative of major items within a Ytterbium-doped diode-pumped fiber laser were selected for testing; including fibers, isolators, combiners, fiber Bragg gratings, and laser diodes. Selection of the components was based on guidelines to test multiple models of typical fiber laser components. A goal of the effort was to test two models (i.e. different manufacturers) of each type of article selected, representing different technologies for the same type of device. The test articles did not include subsystems or systems. These components and parts may not be available commercial-off-the-shelf (COTS), and, in fact, many are custom articles, or newly developed by the manufacturer. The primary goal for this effort is a completed taxonomy that lists all relevant laser components, modules, subsystems, and interfaces, and cites the documentation for space

Technology Assessment of Laser-Assisted Materials Processing in Space

Science.gov (United States)

Nagarathnam, Karthik; Taminger, Karen M. B.

2001-01-01

Lasers are useful for performing operations such as joining, machining, built-up freeform fabrication, shock processing, and surface treatments. These attributes are attractive for the supportability of longer-term missions in space due to the multi-functionality of a single tool and the variety of materials that can be processed. However, current laser technology also has drawbacks for space-based applications, specifically size, power efficiency, lack of robustness, and problems processing highly reflective materials. A review of recent laser developments will be used to show how these issues may be reduced and indicate where further improvement is necessary to realize a laser-based materials processing capability in space. The broad utility of laser beams in synthesizing various classes of engineering materials will be illustrated using state-of-the art processing maps for select lightweight alloys typically found on spacecraft. With the advent of recent breakthroughs in diode-pumped solid-state lasers and fiber optic technologies, the potential to perform multiple processing techniques is increasing significantly. Lasers with suitable wavelengths and beam properties have tremendous potential for supporting future space missions to the moon, Mars and beyond.

Space Solar Power Technology Demonstration for Lunar Polar Applications: Laser-Photovoltaic Wireless Power Transmission

Science.gov (United States)

Henley, M. W.; Fikes, J. C.; Howell, J.; Mankins, J. C.; Howell, Joe T. (Technical Monitor)

2002-01-01

Space Solar Power technology offers unique benefits for near-term NASA space science missions, which can mature this technology for other future applications. "Laser-Photo-Voltaic Wireless Power Transmission" (Laser-PV WPT) is a technology that uses a laser to beam power to a photovoltaic receiver, which converts the laser's light into electricity. Future Laser-PV WPT systems may beam power from Earth to satellites or large Space Solar Power satellites may beam power to Earth, perhaps supplementing terrestrial solar photo-voltaic receivers. In a near-term scientific mission to the moon, Laser-PV WPT can enable robotic operations in permanently shadowed lunar polar craters, which may contain ice. Ground-based technology demonstrations are proceeding, to mature the technology for this initial application, in the moon's polar regions.

Laser transmitter for Lidar In-Space Technology Experiment

Science.gov (United States)

Chang, John; Cimolino, Marc; Petros, Mulugeta

1991-01-01

The Lidar In-Space Technology Experiment (LITE) Laser Transmitter Module (LTM) flight laser optical architecture has been space qualified by extensive testing at the system, subsystem and component level. The projected system output performance has been verified using an optically and electrically similar breadboard version of the laser. Parasitic lasing was closely examined and completely suppressed after design changes were implemented and tested. Oscillator and amplifier type heads were separately tested to 150 million shots. Critical subassemblies have undergone environmental testing to Shuttle qualification levels. A superior three color anti-reflection coating was developed and tested for use on 14 surfaces after the final amplifier.

Solar-pumped lasers for space power transmission

Science.gov (United States)

Taussig, R.; Bruzzone, C.; Nelson, L.; Quimby, D.; Christiansen, W.

1979-01-01

Multi-Megawatt CW solar-pumped lasers appear to be technologically feasible for space power transmission in the 1990s time frame. A new concept for a solar-pumped laser is presented which utilizes an intermediate black body cavity to provide a uniform optical pumping environment for the lasant, either CO or CO2. Reradiation losses are minimized with resulting high efficiency operation. A 1 MW output laser may weigh as little as 8000 kg including solar collector, black body cavity, laser cavity and ducts, pumps, power systems and waste heat radiator. The efficiency of such a system will be on the order of 10 to 20%. Details of the new concept, laser design, comparison to competing solar-powered lasers and applications to a laser solar power satellite (SPS) concept are presented.

Novel Space-based Solar Power Technologies and Architectures for Earth and Beyond

Science.gov (United States)

Howell, Joe T.; Fikes, John C.; O'Neill, Mark J.

2005-01-01

Research, development and studies of novel space-based solar power systems, technologies and architectures for Earth and beyond are needed to reduce the cost of clean electrical power for terrestrial use and to provide a stepping stone for providing an abundance of power in space, i.e., manufacturing facilities, tourist facilities, delivery of power between objects in space, and between space and surface sites. The architectures, technologies and systems needed for space to Earth applications may also be used for in-space applications. Advances in key technologies, i.e., power generation, power management and distribution, power beaming and conversion of beamed power are needed to achieve the objectives of both terrestrial and extraterrestrial applications. Power beaming or wireless power transmission (WPT) can involve lasers or microwaves along with the associated power interfaces. Microwave and laser transmission techniques have been studied with several promising approaches to safe and efficient WPT identified. These investigations have included microwave phased array transmitters, as well as laser transmission and associated optics. There is a need to produce "proof-of-concept" validation of critical WPT technologies for both the near-term, as well as far-term applications. Investments may be harvested in near-term beam safe demonstrations of commercial WPT applications. Receiving sites (users) include ground-based stations for terrestrial electrical power, orbital sites to provide power for satellites and other platforms, future space elevator systems, space vehicle propulsion, and space to surface sites. This paper briefly discusses achieving a promising approach to the solar power generation and beamed power conversion. The approach is based on a unique high-power solar concentrator array called Stretched Lens Array (SLA) for both solar power generation and beamed power conversion. Since both versions (solar and laser) of SLA use many identical components

Free space broad-bandwidth tunable laser diode based on Littman configuration for 3D profile measurement

Science.gov (United States)

Shirazi, Muhammad Faizan; Kim, Pilun; Jeon, Mansik; Kim, Chang-Seok; Kim, Jeehyun

2018-05-01

We developed a tunable laser diode for an optical coherence tomography system that can perform three-dimensional profile measurement using an area scanning technique. The tunable laser diode is designed using an Eagleyard tunable laser diode with a galvano filter. The Littman free space configuration is used to demonstrate laser operation. The line- and bandwidths of this source are 0.27 nm (∼110 GHz) and 43 nm, respectively, at the center wavelength of 860 nm. The output power is 20 mW at an operating current of 150 mA. A step height target is imaged using a wide-area scanning system to show the measurement accuracy of the proposed tunable laser diode. A TEM grid is also imaged to measure the topography and thickness of the sample by proposed tunable laser diode.

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.

Laser and plasma diagnostics for the OMEGA Upgrade Laser System (invited) (abstract)

International Nuclear Information System (INIS)

Letzring, S.A.

1995-01-01

The upgraded OMEGA laser system will be capable of delivering up to 30 kJ of 351-nm laser light with various temporal pulse shapes onto a variety of targets for both ICF and basic plasma physics experiments. ICF experiments will cover a wide parameter space up to near-ignition conditions, and basic interaction and plasma physics experiments will cover previously unattainable parameter spaces. The laser system is the tool with which the experiments are performed; the diagnostics, both of the laser system and the interaction between the laser and the target, form the heart of the experiment. A new suite of diagnostics is now being designed and constructed. Most of these are based on diagnostics previously fielded on the OMEGA laser system very successfully over the last ten years, but there are some new diagnostics, both for the laser and the interaction experiments, which have had to be invented. Laser system diagnostics include high-energy, full-beam calorimetry for all of the 60 beams of the upgrade; a novel, multispectral energy-measuring system for assessing the tuning of the frequency-multiplying crystals; a beam-balance diagnostic that forms the heart of the energy-balance system; and a peak power diagnostic that forms the heart of the power-balance system. Target diagnostics will include the usual time-integrated x-ray imaging systems, both pinhole cameras and x-ray microscopes; x-ray spectrometers, both imaging and spatially integrating; plamsa calorimeters, including x-ray calorimetry; and time-resolved x-ray diagnostics, both nonimaging and imaging in one and two dimensions. Neutron diagnostics will include several measurements of total yield, secondary, and possibly tertiary yield and neutron spectroscopy with several time-of-flight spectrometers. Other measurements will include ''knock-on'' particle measurements and neutron activation of shell materials as a diagnostic of compressed fuel and shell density

First laser measurements to space debris in Poland

Science.gov (United States)

Lejba, Paweł; Suchodolski, Tomasz; Michałek, Piotr; Bartoszak, Jacek; Schillak, Stanisław; Zapaśnik, Stanisław

2018-05-01

The Borowiec Satellite Laser Ranging station (BORL 7811, Borowiec) being a part of the Space Research Centre of the Polish Academy of Sciences (SRC PAS) went through modernization in 2014-2015. One of the main tasks of the modernization was the installation of a high-energy laser module dedicated to space debris tracking. Surelite III by Continuum is a Nd:YAG pulse laser with 10 Hz repetition rate, a pulse width of 3-5 ns and a pulse energy of 450 mJ for green (532 nm). This new laser unit was integrated with the SLR system at Borowiec performing standard satellite tracking. In 2016 BORL 7811 participated actively to the observational campaigns related to the space debris targets from LEO region managed by the Space Debris Study Group (SDSG) of the International Laser Ranging Service (ILRS). Currently, Borowiec station regularly tracks 36 space debris from the LEO regime, including typical rocket bodies (Russian/Chinese) and cooperative targets like the inactive TOPEX/Poseidon, ENVISAT, OICETS and others. In this paper the first results of space debris laser measurements obtained by the Borowiec station in period August 2016 - January 2017 are presented. The results gained by the SRC PAS Borowiec station confirm the rotation of the defunct TOPEX/Poseidon satellite which spins with a period of approximately 10 s. The novelty of this work is the presentation of the sample results of the Chinese CZ-2C R/B target (NORAD catalogue number 31114) which is equipped (probably) with retroreflectors. Laser measurements to space debris is a very desirable topic for the next years, especially in the context of the Space Surveillance and Tracking (SST) activity. Some targets are very easy to track like defunct ENVISAT or TOPEX/Poseidon. On the other hand, there is a big population of different LEO targets with different orbital and physical parameters, which are challenging for laser ranging like small irregular debris and rocket boosters.

Tailoring Laser Propulsion for Future Applications in Space

International Nuclear Information System (INIS)

Eckel, Hans-Albert; Scharring, Stefan

2010-01-01

Pulsed laser propulsion may turn out as a low cost alternative for the transportation of small payloads in future. In recent years DLR investigated this technology with the goal of cheaply launching small satellites into low earth orbit (LEO) with payload masses on the order of 5 to 10 kg. Since the required high power pulsed laser sources are yet not at the horizon, DLR focused on new applications based on available laser technology. Space-borne, i.e. in weightlessness, there exist a wide range of missions requiring small thrusters that can be propelled by laser power. This covers space logistic and sample return missions as well as position keeping and attitude control of satellites.First, a report on the proof of concept of a remote controlled laser rocket with a thrust vector steering device integrated in a parabolic nozzle will be given. Second, the road from the previous ground-based flight experiments in earth's gravity using a 100-J class laser to flight experiments with a parabolic thruster in an artificial 2D-zero gravity on an air cushion table employing a 1-J class laser and, with even less energy, new investigations in the field of laser micro propulsion will be reviewed.

A Multi-Component Automated Laser-Origami System for Cyber-Manufacturing

Science.gov (United States)

Ko, Woo-Hyun; Srinivasa, Arun; Kumar, P. R.

2017-12-01

Cyber-manufacturing systems can be enhanced by an integrated network architecture that is easily configurable, reliable, and scalable. We consider a cyber-physical system for use in an origami-type laser-based custom manufacturing machine employing folding and cutting of sheet material to manufacture 3D objects. We have developed such a system for use in a laser-based autonomous custom manufacturing machine equipped with real-time sensing and control. The basic elements in the architecture are built around the laser processing machine. They include a sensing system to estimate the state of the workpiece, a control system determining control inputs for a laser system based on the estimated data and user’s job requests, a robotic arm manipulating the workpiece in the work space, and middleware, named Etherware, supporting the communication among the systems. We demonstrate automated 3D laser cutting and bending to fabricate a 3D product as an experimental result.

Space imaging measurement system based on fixed lens and moving detector

Science.gov (United States)

Akiyama, Akira; Doshida, Minoru; Mutoh, Eiichiro; Kumagai, Hideo; Yamada, Hirofumi; Ishii, Hiromitsu

2006-08-01

We have developed the Space Imaging Measurement System based on the fixed lens and fast moving detector to the control of the autonomous ground vehicle. The space measurement is the most important task in the development of the autonomous ground vehicle. In this study we move the detector back and forth along the optical axis at the fast rate to measure the three-dimensional image data. This system is just appropriate to the autonomous ground vehicle because this system does not send out any optical energy to measure the distance and keep the safety. And we use the digital camera of the visible ray range. Therefore it gives us the cost reduction of the three-dimensional image data acquisition with respect to the imaging laser system. We can combine many pieces of the narrow space imaging measurement data to construct the wide range three-dimensional data. This gives us the improvement of the image recognition with respect to the object space. To develop the fast movement of the detector, we build the counter mass balance in the mechanical crank system of the Space Imaging Measurement System. And then we set up the duct to prevent the optical noise due to the ray not coming through lens. The object distance is derived from the focus distance which related to the best focused image data. The best focused image data is selected from the image of the maximum standard deviation in the standard deviations of series images.

Problems in the development of autonomous mobile laser systems based on a cw chemical DF laser

International Nuclear Information System (INIS)

Aleksandrov, B P; Bashkin, A S; Beznozdrev, V N; Parfen'ev, M V; Pirogov, N A; Semenov, S N

2003-01-01

The problems involved in designing autonomous mobile laser systems based on high-power cw chemical DF lasers, whose mass and size parameters would make it possible to install them on various vehicles, are discussed. The need for mobility of such lasers necessitates special attention to be paid to the quest for ways and means of reducing the mass and size of the main laser systems. The optimisation of the parameters of such lasers is studied for various methods of scaling their systems. A complex approach to analysis of the optical scheme of the laser system is developed. (special issue devoted to the 80th anniversary of academician n g basov's birth)

Scientific applications of frequency-stabilized laser technology in space

Science.gov (United States)

Schumaker, Bonny L.

1990-01-01

A synoptic investigation of the uses of frequency-stabilized lasers for scientific applications in space is presented. It begins by summarizing properties of lasers, characterizing their frequency stability, and describing limitations and techniques to achieve certain levels of frequency stability. Limits to precision set by laser frequency stability for various kinds of measurements are investigated and compared with other sources of error. These other sources include photon-counting statistics, scattered laser light, fluctuations in laser power, and intensity distribution across the beam, propagation effects, mechanical and thermal noise, and radiation pressure. Methods are explored to improve the sensitivity of laser-based interferometric and range-rate measurements. Several specific types of science experiments that rely on highly precise measurements made with lasers are analyzed, and anticipated errors and overall performance are discussed. Qualitative descriptions are given of a number of other possible science applications involving frequency-stabilized lasers and related laser technology in space. These applications will warrant more careful analysis as technology develops.

Research on laser cladding control system based on fuzzy PID

Science.gov (United States)

Zhang, Chuanwei; Yu, Zhengyang

2017-12-01

Laser cladding technology has a high demand for control system, and the domestic laser cladding control system mostly uses the traditional PID control algorithm. Therefore, the laser cladding control system has a lot of room for improvement. This feature is suitable for laser cladding technology, Based on fuzzy PID three closed-loop control system, and compared with the conventional PID; At the same time, the laser cladding experiment and friction and wear experiment were carried out under the premise of ensuring the reasonable control system. Experiments show that compared with the conventional PID algorithm in fuzzy the PID algorithm under the surface of the cladding layer is more smooth, the surface roughness increases, and the wear resistance of the cladding layer is also enhanced.

Testing of a femtosecond pulse laser in outer space

Science.gov (United States)

Lee, Joohyung; Lee, Keunwoo; Jang, Yoon-Soo; Jang, Heesuk; Han, Seongheum; Lee, Sang-Hyun; Kang, Kyung-In; Lim, Chul-Woo; Kim, Young-Jin; Kim, Seung-Woo

2014-01-01

We report a test operation of an Er-doped fibre femtosecond laser which was conducted for the first time in outer space. The fibre-based ultrashort pulse laser payload was designed to meet space-use requirements, undergone through ground qualification tests and finally launched into a low-earth orbit early in 2013. Test results obtained during a one-year mission lifetime confirmed stable mode-locking all the way through although the radiation induced attenuation (RIA) in the Er-doped gain fibre caused an 8.6% reduction in the output power. This successful test operation would help facilitate diverse scientific and technological applications of femtosecond lasers in space and earth atmosphere in the near future. PMID:24875665

Automatic Laser Pointer Detection Algorithm for Environment Control Device Systems Based on Template Matching and Genetic Tuning of Fuzzy Rule-Based Systems

Directory of Open Access Journals (Sweden)

F.

2012-04-01

Full Text Available In this paper we propose a new approach for laser-based environment device control systems based on the automatic design of a Fuzzy Rule-Based System for laser pointer detection. The idea is to improve the success rate of the previous approaches decreasing as much as possible the false offs and increasing the success rate in images with laser spot, i.e., the detection of a false laser spot (since this could lead to dangerous situations. To this end, we propose to analyze both, the morphology and color of a laser spot image together, thus developing a new robust algorithm. Genetic Fuzzy Systems have also been employed to improve the laser spot system detection by means of a fine tuning of the involved membership functions thus reducing the system false offs, which is the main objective in this problem. The system presented in this paper, makes use of a Fuzzy Rule-Based System adjusted by a Genetic Algorithm, which, based on laser morphology and color analysis, shows a better success rate than previous approaches.

Free-space laser communication technologies II; Proceedings of the Meeting, Los Angeles, CA, Jan. 15-17, 1990

Science.gov (United States)

Begley, David L. (Editor); Seery, Bernard D. (Editor)

1990-01-01

Various papers on free-space laser communication technologies are presented. Individual topics addressed include: optical intersatellite link experiment between the earth station and ETS-VI, the Goddard optical communications program, technologies and techniques for lasercom terminal size, weight, and cost reduction, laser beam acquisition and tracking system for ETS-VI laser communication equipment, analog dividers for acquisition and tracking signal normalization, fine pointing mechanism using multilayered piezoelectric actuator for optical ISL system, analysis of SILEX tracking sensor performance, new telescope concept for space communication, telescope considered as a very high gain antenna, design of compact transceiver optical systems for optical intersatellite links, ultralightweight optics for laser communications, highly sensitive measurement method for stray light and retroreflected light, depolarization effects on free space laser transceiver communication systems, in-orbit measurements of microaccelerations of ESA's communication satellite Olympus, high-performance laser diode transmitter for optical free space communication, diode-pumped Nd:host laser transmitter for intersatellite optical communications, single-frequency diode-pumped laser for free-space communication.

A Laser-based Ultrasonic Inspection System to Detect Micro Fatigue Cracks

International Nuclear Information System (INIS)

Park, Seung Kyu; Baik, Sung Hoon; Park, Moon Cheol; Lim, Chang Hwan; Cha, Hyung Ki

2005-01-01

Laser-based ultrasonic techniques have been established as a viable non-contact alternative to piezoelectric transducers for generating and receiving ultrasound. Laser-based ultrasonic inspection system provides a number of advantages over the conventional generation by piezoelectric transducers, especially a non-contact generation and detection of ultrasonic waves, high spatial scanning resolution, controllable narrow-band and wide-band spectrum, absolute measurements of the moving distance, use of fiber optics, and an ability to operate on curved and rough surfaces and at hard-to-access locations like a nuclear power plant. Ochiai and Miura used the laser-based ultrasound to detect micro fatigue cracks for the inspection of a material degradation in nuclear power plants. This widely applicable laser-based ultrasonic inspection system is comparatively expensive and provides low signal-to-noise ratio to measure ultrasound by using the laser interferometer. Many studies have been carried out to improve the measuring efficiency of the laser interferometer. One of the widely used laser interferometer types to measure the ultrasound is the Confocal Fabry-Perot Interferometer(CFPI). The measurement gain of the CFPI is slightly and continually varied according to the small change of the cavity length and the fluctuations of the measuring laser beam frequency with time. If we continually adjust the voltage of a PZT which is fixed to one of the interferometer mirrors, the optimum working point of the CFPI can be fixed. Though a static stabilizer can fix the gain of the CFPI where the CW laser beam is targeted at one position, it can not be used when the CW laser beam is scanned like a scanning laser source(SLS) technique. A dynamic stabilizer can be used for the scanning ultrasonic inspection system. A robust dynamic stabilizer is needed for an application to the industrial inspection fields. Kromine showed that the SLS technique is effective to detect small fatigue cracks

Simulation analysis of impulse characteristics of space debris irradiated by multi-pulse laser

Science.gov (United States)

Lin, Zhengguo; Jin, Xing; Chang, Hao; You, Xiangyu

2018-02-01

Cleaning space debris with laser is a hot topic in the field of space security research. Impulse characteristics are the basis of cleaning space debris with laser. In order to study the impulse characteristics of rotating irregular space debris irradiated by multi-pulse laser, the impulse calculation method of rotating space debris irradiated by multi-pulse laser is established based on the area matrix method. The calculation method of impulse and impulsive moment under multi-pulse irradiation is given. The calculation process of total impulse under multi-pulse irradiation is analyzed. With a typical non-planar space debris (cube) as example, the impulse characteristics of space debris irradiated by multi-pulse laser are simulated and analyzed. The effects of initial angular velocity, spot size and pulse frequency on impulse characteristics are investigated.

Iterative Decoding for an Optical CDMA based Laser communication System

International Nuclear Information System (INIS)

Kim, Jin Young; Kim, Eun Cheol; Cha, Jae Sang

2008-01-01

An optical CDMA(code division multiple access)based Laser communication system has attracted much attention since it requires minimal optical Laser signal processing and it is virtually delay free, while from the theoretical point of view, its performance depends on the auto and cross correlation properties of employed sequences. Various kinds of channel coding schemes for optical CDMA based Laser communication systems have been proposed and analyzed to compensate nonideal channel and receiver conditions in impaired photon channels. In this paper, we propose and analyze an iterative decoding of optical CDMA based Laser communication signals for both shot noise limited and thermal noise limited systems. It is assumed that optical channel is an intensity modulated (IM)channel and direct detection scheme is employed to detect the received optical signal. The performance is evaluated in terms of bit error probability and throughput. It is demonstrated that the BER and throughput performance is substantially improved with interleaver length for a fixed code rate and with alphabet size of PPM (pulse position modulation). Also, the BER and throughput performance is significantly enhanced with the number of iterations for decoding process. The results in this paper can be applied to the optical CDMA based Laser communication network with multiple access applications

Iterative Decoding for an Optical CDMA based Laser communication System

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Young; Kim, Eun Cheol [Kwangwoon Univ., Seoul (Korea, Republic of); Cha, Jae Sang [Seoul National Univ. of Technology, Seoul (Korea, Republic of)

2008-11-15

An optical CDMA(code division multiple access)based Laser communication system has attracted much attention since it requires minimal optical Laser signal processing and it is virtually delay free, while from the theoretical point of view, its performance depends on the auto and cross correlation properties of employed sequences. Various kinds of channel coding schemes for optical CDMA based Laser communication systems have been proposed and analyzed to compensate nonideal channel and receiver conditions in impaired photon channels. In this paper, we propose and analyze an iterative decoding of optical CDMA based Laser communication signals for both shot noise limited and thermal noise limited systems. It is assumed that optical channel is an intensity modulated (IM)channel and direct detection scheme is employed to detect the received optical signal. The performance is evaluated in terms of bit error probability and throughput. It is demonstrated that the BER and throughput performance is substantially improved with interleaver length for a fixed code rate and with alphabet size of PPM (pulse position modulation). Also, the BER and throughput performance is significantly enhanced with the number of iterations for decoding process. The results in this paper can be applied to the optical CDMA based Laser communication network with multiple access applications.

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.

Modeling of photoluminescence in laser-based lighting systems

Science.gov (United States)

Chatzizyrli, Elisavet; Tinne, Nadine; Lachmayer, Roland; Neumann, Jörg; Kracht, Dietmar

2017-12-01

The development of laser-based lighting systems has been the latest step towards a revolution in illumination technology brought about by solid-state lighting. Laser-activated remote phosphor systems produce white light sources with significantly higher luminance than LEDs. The weak point of such systems is often considered to be the conversion element. The high-intensity exciting laser beam in combination with the limited thermal conductivity of ceramic phosphor materials leads to thermal quenching, the phenomenon in which the emission efficiency decreases as temperature rises. For this reason, the aim of the presented study is the modeling of remote phosphor systems in order to investigate their thermal limitations and to calculate the parameters for optimizing the efficiency of such systems. The common approach to simulate remote phosphor systems utilizes a combination of different tools such as ray tracing algorithms and wave optics tools for describing the incident and converted light, whereas the modeling of the conversion process itself, i.e. photoluminescence, in most cases is circumvented by using the absorption and emission spectra of the phosphor material. In this study, we describe the processes involved in luminescence quantum-mechanically using the single-configurational-coordinate diagram as well as the Franck-Condon principle and propose a simulation model that incorporates the temperature dependence of these processes. Following an increasing awareness of climate change and environmental issues, the development of ecologically friendly lighting systems featuring low power consumption and high luminous efficiency is imperative more than ever. The better understanding of laser-based lighting systems is an important step towards that aim as they may improve on LEDs in the near future.

MBE System for Antimonide Based Semiconductor Lasers

National Research Council Canada - National Science Library

Lester, Luke

1999-01-01

.... SLR-770 inductively coupled plasma (ICP) processing system. The SLR-770 has been invaluable in the study of plasma etching of AlGaAsSb and GaSb-materials that form the backbone of antimonide-based semiconductor lasers...

Laser space debris removal: now, not later

Science.gov (United States)

Phipps, Claude R.

2015-02-01

Small (1-10cm) debris in low Earth orbit (LEO) are extremely dangerous, because they spread the breakup cascade depicted in the movie "Gravity." Laser-Debris-Removal (LDR) is the only solution that can address both large and small debris. In this paper, we briefly review ground-based LDR, and discuss how a polar location can dramatically increase its effectiveness for the important class of sun-synchronous orbit (SSO) objects. No other solutions address the whole problem of large ( 1000cm, 1 ton) as well as small debris. Physical removal of small debris (by nets, tethers and so on) is impractical because of the energy cost of matching orbits. We also discuss a new proposal which uses a space-based station in low Earth orbit (LEO), and rapid, head-on interaction in 10- 40s rather than 4 minutes, with high-power bursts of 100ps, 355nm pulses from a 1.5m diameter aperture. The orbiting station employs "heat-capacity" laser mode with low duty cycle to create an adaptable, robust, dualmode system which can lower or raise large derelict objects into less dangerous orbits, as well as clear out the small debris in a 400-km thick LEO band. Time-average laser optical power is less than 15kW. The combination of short pulses and UV wavelength gives lower required energy density (fluence) on target as well as higher momentum coupling coefficient. This combination leads to much smaller mirrors and lower average power than the ground-based systems we have considered previously. Our system also permits strong defense of specific assets. Analysis gives an estimated cost of about 1k each to re-enter most small debris in a few months, and about 280k each to raise or lower 1-ton objects by 40km. We believe it can do this for 2,000 such large objects in about four years. Laser ablation is one of the few interactions in nature that propel a distant object without any significant reaction on the source.

Materials for spaceborne laser systems

International Nuclear Information System (INIS)

Gusarov, A.

2006-01-01

Advanced laser systems are attracting a growing interest for space missions, in particular for LIDAR (LIght Detection And Ranging) applications. An important issue for the LIDARs is the very strict requirements on the optical performance and more specifically the need for a high optical output power combined with a nearly perfect output beam quality. These features are traditionally in conflict with each other. Thermally induced phase distortions indeed corrupt the beam quality of high-power solid-state lasers and it becomes increasingly difficult to maintain a good beam quality while increasing the output power. A possible solution of the problem is to use the optical phase conjugation, which provides a method to dynamically correct for those aberrations. A process by which phase-conjugated waves can be generated is the SBS (stimulated Brillouin scattering). SBS mirrors commonly used in terrestrial application are based on liquids or gases, which are not 'space-friendly' and often toxic. The solid-state alternative seems the most appropriate for space. Such PCMs (Phase-Conjugating Mirrors) have been the subject of many research efforts in recent years and a significant progress in improving their characteristics has been achieved. However, the issue of space qualification remains open. To address it, the European Space Agency initiated in 2004 the research project named Solid-State Phase Conjugation, Radiation Testing and Evaluation for Core Laser Technologies with the TRT (Thales Research and Technology), France, as the prime contractor, and the CSL (Centre Spatial de Liege) and SCKCEN as the subcontractors. The project is to be completed in 2006. To qualify a PCM for a spaceborne laser system, one has to address a number of specific issues. Such a component must be mechanically rugged to sustain vibrations during the launch phase, provide a low out-gassing to prevent optical surfaces contamination in vacuum, be highly reliable to operate properly without

PERFORMANCE OPTIMIZATION OF THE DIODE-PUMPED SOLID-STATE LASER FOR SPACE APPLICATIONS

Directory of Open Access Journals (Sweden)

D. A. Arkhipov

2015-11-01

Full Text Available Subject of Research. Thermophysical and optical techniques of parameter regulation for diode pumped solid-state laser are studied as applied to space laser communication and laser ranging lines. Methods. The investigations are carried out on the base of the original design of diode pumped solid-state laser module that includes the following: Nd:YAG slab element, diode pumped by 400W QCW produced by NORTHROP GRUMMAN; two-pass unstable resonator with rotation of the laser beam aperture about its axis through 1800; the output mirror of the resonator with a variable reflection coefficient; hyperthermal conductive plates for thermal stabilization of the laser diode generation modes. The presence of thermal conductive plates excludes conventional running water systems applied as cooling systems for solid-state laser components. The diodes temperature stabilization is achieved by applying the algorithm of pulse-width modulation of power of auxiliary electric heaters. To compensate for non-stationary thermal distortions of the slab refractive index, the laser resonator scheme comprises a prism reflector with an apex angle of 1200. Narrow sides of the prism are covered with reflective coating, and its wide side is sprayed with antireflection coating. The beam aperture is turned around its axis through 1800 because of triple reflection of the beam inside the prism. The turning procedure leads to compensating for the output beam phase distortions in view of symmetric character of the aberrations of slab refractive index. To suppress parasitic oscillations inside the slab, dielectric coatings of wide sides of the slab are used. Main Results. We have demonstrated theoretically and experimentally that the usage of hyperthermal conductive plates together with the algorithm of pulse-width modulation provides stabilizing of the diode substrate temperature accurate within ± 0.1 °С and smoothing the temperature distribution along the plate surface accurate

Free-space laser communication technologies III; Proceedings of the Meeting, Los Angeles, CA, Jan. 21, 22, 1991

Science.gov (United States)

Begley, David L. (Editor); Seery, Bernard D. (Editor)

1991-01-01

The present volume on free-space laser communication technologies discusses system analysis, performance, and applications, pointing, acquisition, and tracking in beam control, laboratory demonstration systems, and transmitter and critical component technologies. Attention is given to a space station laser communication transceiver, meeting intersatellite links mission requirements by an adequate optical terminal design, an optical approach to proximity-operations communications for Space Station Freedom, and optical space-to-ground link availability assessment and diversity requirements. Topics addressed include nonmechanical steering of laser beams by multiple aperture antennas, a free-space simulator for laser transmission, heterodyne acquisition and tracking in a free-space diode laser link, and laser terminal attitude determination via autonomous star tracking. Also discussed are stability considerations in relay lens design for optical communications, liquid crystals for lasercom applications, and narrowband optical interference filters.

Status of High Data Rate Intersatellite Laser Communication as an Enabler for Earth and Space Science

Science.gov (United States)

Heine, F.; Zech, H.; Motzigemba, M.

2017-12-01

Space based laser communication is supporting earth observation and science missions with Gbps data download capabilities. Currently the Sentinel 1 and Sentinel 2 spacecrafts from the Copernicus earth observation program of the European Commission are using the Gbps laser communication links developed by Tesat Spacecom to download low latency data products via a commercial geostationary laser relay station- the European Data Relay Service- (EDRS) as a standard data path, in parallel to the conventional radio frequency links. The paper reports on the status of high bandwidth space laser communication as an enabler for small and large space science missions ranging from cube sat applications in low earth orbit to deep space missions. Space based laser communication has left the experimental phase and will support space science missions with unprecedented data rates.

Recent space nuclear power systems

International Nuclear Information System (INIS)

Takizuka, Takakazu; Yasuda, Hideshi; Hishida, Makoto

1991-01-01

For the advance of mankind into the space, the power sources of large output are indispensable, and it has been considered that atomic energy is promising as compared with solar energy and others. Accordingly in USA and USSR, the development of the nuclear power generation systems for space use has been carried out since considerable years ago. In this report, the general features of space nuclear reactors are shown, and by taking the system for the SP-100 project being carried out in USA as the example, the contents of the recent design regarding the safety as an important factor are discussed. Moreover, as the examples of utilizing space nuclear reactors, the concepts of the power source for the base on the moon, the sources of propulsive power for the rockets used for Mars exploration and others, the remote power transmission system by laser in the space and so on are explained. In September, 1988, the launching of a space shuttle of USA was resumed, and the Jupiter explorer 'Galileo' and the space telescope 'Hubble' were successfully launched. The space station 'Mir' of USSR has been used since February, 1986. The history of the development of the nuclear power generation systems for space use is described. (K.I.)

Progress in diode-pumped alexandrite lasers as a new resource for future space lidar missions

Science.gov (United States)

Damzen, M. J.; Thomas, G. M.; Teppitaksak, A.; Minassian, A.

2017-11-01

Satellite-based remote sensing using laser-based lidar techniques provides a powerful tool for global 3-D mapping of atmospheric species (e.g. CO2, ozone, clouds, aerosols), physical attributes of the atmosphere (e.g. temperature, wind speed), and spectral indicators of Earth features (e.g. vegetation, water). Such information provides a valuable source for weather prediction, understanding of climate change, atmospheric science and health of the Earth eco-system. Similarly, laser-based altimetry can provide high precision ground topography mapping and more complex 3-D mapping (e.g. canopy height profiling). The lidar technique requires use of cutting-edge laser technologies and engineered designs that are capable of enduring the space environment over the mission lifetime. The laser must operate with suitably high electrical-to-optical efficiency and risk reduction strategy adopted to mitigate against laser failure or excessive operational degradation of laser performance.

Space construction base control system

Science.gov (United States)

1978-01-01

Aspects of an attitude control system were studied and developed for a large space base that is structurally flexible and whose mass properties change rather dramatically during its orbital lifetime. Topics of discussion include the following: (1) space base orbital pointing and maneuvering; (2) angular momentum sizing of actuators; (3) momentum desaturation selection and sizing; (4) multilevel control technique applied to configuration one; (5) one-dimensional model simulation; (6) N-body discrete coordinate simulation; (7) structural analysis math model formulation; and (8) discussion of control problems and control methods.

Land-Based Mobile Laser Scanning Systems: a Review

Science.gov (United States)

Puente, I.; González-Jorge, H.; Arias, P.; Armesto, J.

2011-09-01

Mobile mapping has been using various photogrammetric techniques for many years. In recent years, there has been an increase in the number of mobile mapping systems using laser scanners available in the market, partially because of the improvement in GNSS/INS performance for direct georeferencing. In this article, some of the most important land-based mobile laser scanning (MLS) systems are reviewed. Firstly, the main characteristics of MLS systems vs. airborne (ALS) and terrestrial laser scanning (TLS) systems are compared. Secondly, a short overview of the mobile mapping technology is also provided so that the reader can fully grasp the complexity and operation of these devices. As we put forward in this paper, a comparison of different systems is briefly carried out regarding specifications provided by the manufacturers. Focuses on the current research are also addressed with emphasis on the practical applications of these systems. Most of them have been utilized for data collection on road infrastructures or building façades. This article shows that MLS technology is nowadays well established and proven, since the demand has grown to the point that there are several systems suppliers offering their products to satisfy this particular market.

Laser-powered lunar base

International Nuclear Information System (INIS)

Costen, R.; Humes, D.H.; Walker, G.H.; Williams, M.D.; Deyoung, R.J.

1989-01-01

The objective was to compare a nuclear reactor-driven Sterling engine lunar base power source to a laser-to-electric converter with orbiting laser power station, each providing 1 MW of electricity to the lunar base. The comparison was made on the basis of total mass required in low-Earth-orbit for each system. This total mass includes transportation mass required to place systems in low-lunar orbit or on the lunar surface. The nuclear reactor with Sterling engines is considered the reference mission for lunar base power and is described first. The details of the laser-to-electric converter and mass are discussed. The next two solar-driven high-power laser concepts, the diode array laser or the iodine laser system, are discussed with associated masses in low-lunar-orbit. Finally, the payoff for laser-power beaming is summarized

Laser-based agriculture system

KAUST Repository

Ooi, Boon S.

2016-03-31

A system and method are provided for indoor agriculture using at least one growth chamber illuminated by laser light. In an example embodiment of the agriculture system, a growth chamber is provided having one or more walls defining an interior portion of the growth chamber. The agriculture system may include a removable tray disposed within the interior portion of the growth chamber. The agriculture system also includes a light source, which may be disposed outside the growth chamber. The one or more walls may include at least one aperture. The light source is configured to illuminate at least a part of the interior portion of the growth chamber. In embodiments in which the light source is disposed outside the growth chamber, the light source is configured to transmit the laser light to the interior portion of the growth chamber via the at least one aperture.

Laser-based agriculture system

KAUST Repository

Ooi, Boon S.; Wong, Aloysius Tze; Ng, Tien Khee

2016-01-01

A system and method are provided for indoor agriculture using at least one growth chamber illuminated by laser light. In an example embodiment of the agriculture system, a growth chamber is provided having one or more walls defining an interior portion of the growth chamber. The agriculture system may include a removable tray disposed within the interior portion of the growth chamber. The agriculture system also includes a light source, which may be disposed outside the growth chamber. The one or more walls may include at least one aperture. The light source is configured to illuminate at least a part of the interior portion of the growth chamber. In embodiments in which the light source is disposed outside the growth chamber, the light source is configured to transmit the laser light to the interior portion of the growth chamber via the at least one aperture.

Polarization-free Cubic Phase GaN Ultraviolet Laser Diodes for Space-based Light Interferometry

Data.gov (United States)

National Aeronautics and Space Administration — Laser diodes have many advantages over other forms of lasers: extremely compact (<1cm in length), inexpensive and simple designs that can achieve high power, high...

Efficient TEA CO2 laser based coating removal system

CSIR Research Space (South Africa)

Prinsloo, FJ

2007-04-01

Full Text Available stream_source_info Prinsloo_2007.pdf.txt stream_content_type text/plain stream_size 11617 Content-Encoding UTF-8 stream_name Prinsloo_2007.pdf.txt Content-Type text/plain; charset=UTF-8 Efficient TEA CO2 laser based... by keeping energy density below the damage threshold. The advantage of a pulsed TEA CO2 laser system is that a laser frequency and temporal profile can be chosen to maximize paint removal and concurrently minimize substrate damage. To achieve...

Lidar technologies for airborne and space-based applications

International Nuclear Information System (INIS)

Henson, T.D.; Schmitt, R.L.; Sobering, T.J.; Raymond, T.D.; Stephenson, D.A.

1994-10-01

This study identifies technologies required to extend the capabilities of airborne light detection and ranging (lidar) systems and establish the feasibility of autonomous space-based lidars. Work focused on technologies that enable the development of a lightweight, low power, rugged and autonomous Differential Absorption Lidar (DIAL) instruments. Applications for airborne or space-based DIAL include the measurement of water vapor profiles in support of climate research and processing-plant emissions signatures for environmental and nonproliferation monitoring. A computer-based lidar performance model was developed to allow trade studies to be performed on various technologies and system configurations. It combines input from the physics (absorption line strengths and locations) of the problem, the system requirements (weight, power, volume, accuracy), and the critical technologies available (detectors, lasers, filters) to produce the best conceptual design. Conceptual designs for an airborne and space-based water vapor DIAL, and a detailed design of a ground-based water vapor DIAL demonstration system were completed. Future work planned includes the final testing, integration, and operation of the demonstration system to prove the capability of the critical enabling technologies identified

Relativity effects for space-based coherent lidar experiments

Science.gov (United States)

Gudimetla, V. S. Rao

1996-01-01

An effort was initiated last year in the Astrionics Laboratory at Marshall Space Flight Center to examine and incorporate, if necessary, the effects of relativity in the design of space-based lidar systems. A space-based lidar system, named AEOLUS, is under development at Marshall Space Flight Center and it will be used to accurately measure atmospheric wind profiles. Effects of relativity were also observed in the performance of space-based systems, for example in case of global positioning systems, and corrections were incorporated into the design of instruments. During the last summer, the effects of special relativity on the design of space-based lidar systems were studied in detail, by analyzing the problem of laser scattering off a fixed target when the source and a co-located receiver are moving on a spacecraft. Since the proposed lidar system uses a coherent detection system, errors even in the order of a few microradians must be corrected to achieve a good signal-to-noise ratio. Previous analysis assumed that the ground is flat and the spacecraft is moving parallel to the ground, and developed analytical expressions for the location, direction and Doppler shift of the returning radiation. Because of the assumptions used in that analysis, only special relativity effects were involved. In this report, that analysis is extended to include general relativity and calculate its effects on the design.

Implementation of the laser-based femtosecond precision synchronization system at FLASH

International Nuclear Information System (INIS)

Schulz, Sebastian

2011-05-01

FLASH, the high-gain free-electron laser (FEL) in Hamburg, enables the generation of light pulses with wavelengths in the soft X-ray region and durations down to a few femtoseconds. To fully exploit this capability in time-resolved pump-probe experiments, and for the projected externally seeded operation, the critical components of the accelerator and several external laser systems have to be synchronized with a temporal accuracy at least in the same order of magnitude. This can not be realized purely with established RF-based systems and therefore, an optical, laser-based synchronization system is required. In this thesis, the optical synchronization system of FLASH has been, based on previous successful proof-of-principle experiments, massively extended. One major topic is the comprehensive characterization of the timing reference of the system and a comparison of different types of such master laser oscillators, as well as studies on their short- and long-term stability. Similar investigations have been carried out for the upgraded and newly installed length-stabilized fiber links, which connect the remote locations at the accelerator to the optical timing reference. The successful demonstration of an all-optical synchronization of a Ti:sapphire oscillator with sub-10 femtosecond timing jitter and the connection of the photo injector laser system to the synchronization system mark further important key experiments of this thesis. The robustness of the actual implementations played a key role, as the synchronization system forms the basis for the future, operator-friendly arrival time feedback.

A vision-based system for fast and accurate laser scanning in robot-assisted phonomicrosurgery.

Science.gov (United States)

Dagnino, Giulio; Mattos, Leonardo S; Caldwell, Darwin G

2015-02-01

Surgical quality in phonomicrosurgery can be improved by open-loop laser control (e.g., high-speed scanning capabilities) with a robust and accurate closed-loop visual servoing systems. A new vision-based system for laser scanning control during robot-assisted phonomicrosurgery was developed and tested. Laser scanning was accomplished with a dual control strategy, which adds a vision-based trajectory correction phase to a fast open-loop laser controller. The system is designed to eliminate open-loop aiming errors caused by system calibration limitations and by the unpredictable topology of real targets. Evaluation of the new system was performed using CO(2) laser cutting trials on artificial targets and ex-vivo tissue. This system produced accuracy values corresponding to pixel resolution even when smoke created by the laser-target interaction clutters the camera view. In realistic test scenarios, trajectory following RMS errors were reduced by almost 80 % with respect to open-loop system performances, reaching mean error values around 30 μ m and maximum observed errors in the order of 60 μ m. A new vision-based laser microsurgical control system was shown to be effective and promising with significant positive potential impact on the safety and quality of laser microsurgeries.

High-level PC-based laser system modeling

Science.gov (United States)

Taylor, Michael S.

1991-05-01

Since the inception of the Strategic Defense Initiative (SDI) there have been a multitude of comparison studies done in an attempt to evaluate the effectiveness and relative sizes of complementary, and sometimes competitive, laser weapon systems. It became more and more apparent that what the systems analyst needed was not only a fast, but a cost effective way to perform high-level trade studies. In the present investigation, a general procedure is presented for the development of PC-based algorithmic systems models for laser systems. This procedure points out all of the major issues that should be addressed in the design and development of such a model. Issues addressed include defining the problem to be modeled, defining a strategy for development, and finally, effective use of the model once developed. Being a general procedure, it will allow a systems analyst to develop a model to meet specific needs. To illustrate this method of model development, a description of the Strategic Defense Simulation - Design To (SDS-DT) model developed and used by Science Applications International Corporation (SAIC) is presented. SDS-DT is a menu-driven, fast executing, PC-based program that can be used to either calculate performance, weight, volume, and cost values for a particular design or, alternatively, to run parametrics on particular system parameters to perhaps optimize a design.

Laser Remediation of Threats Posed by Small Orbital Debris

Science.gov (United States)

Fork, Richard L.; Rogers, Jan R.; Hovater, Mary A.

2012-01-01

The continually increasing amount of orbital debris in near Earth space poses an increasing challenge to space situational awareness. Recent collisions of spacecraft caused abrupt increases in the density of both large and small debris in near Earth space. An especially challenging class of threats is that due to the increasing density of small (1 mm to 10 cm dimension) orbital debris. This small debris poses a serious threat since: (1) The high velocity enables even millimeter dimension debris to cause serious damage to vulnerable areas of space assets, e.g., detector windows; (2) The small size and large number of debris elements prevent adequate detection and cataloguing. We have identified solutions to this threat in the form of novel laser systems and novel ways of using these laser systems. While implementation of the solutions we identify is challenging we find approaches offering threat mitigation within time frames and at costs of practical interest. We base our analysis on the unique combination of coherent light specifically structured in both space and time and applied in novel ways entirely within the vacuum of space to deorbiting small debris. We compare and contrast laser based small debris removal strategies using ground based laser systems with strategies using space based laser systems. We find laser systems located and used entirely within space offer essential and decisive advantages over groundbased laser systems.

Process observation in fiber laser-based selective laser melting

Science.gov (United States)

Thombansen, Ulrich; Gatej, Alexander; Pereira, Milton

2015-01-01

The process observation in selective laser melting (SLM) focuses on observing the interaction point where the powder is processed. To provide process relevant information, signals have to be acquired that are resolved in both time and space. Especially in high-power SLM, where more than 1 kW of laser power is used, processing speeds of several meters per second are required for a high-quality processing results. Therefore, an implementation of a suitable process observation system has to acquire a large amount of spatially resolved data at low sampling speeds or it has to restrict the acquisition to a predefined area at a high sampling speed. In any case, it is vitally important to synchronously record the laser beam position and the acquired signal. This is a prerequisite that allows the recorded data become information. Today, most SLM systems employ f-theta lenses to focus the processing laser beam onto the powder bed. This report describes the drawbacks that result for process observation and suggests a variable retro-focus system which solves these issues. The beam quality of fiber lasers delivers the processing laser beam to the powder bed at relevant focus diameters, which is a key prerequisite for this solution to be viable. The optical train we present here couples the processing laser beam and the process observation coaxially, ensuring consistent alignment of interaction zone and observed area. With respect to signal processing, we have developed a solution that synchronously acquires signals from a pyrometer and the position of the laser beam by sampling the data with a field programmable gate array. The relevance of the acquired signals has been validated by the scanning of a sample filament. Experiments with grooved samples show a correlation between different powder thicknesses and the acquired signals at relevant processing parameters. This basic work takes a first step toward self-optimization of the manufacturing process in SLM. It enables the

A laser particulate spectrometer for a space simulation facility

Science.gov (United States)

Schmitt, R. J.; Boyd, B. A.; Linford, R. M. F.; Richmond, R. G.

1975-01-01

A laser particulate spectrometer (LPS) system was developed to measure the size and speed distributions of particulate contaminants. Detection of the particulates is achieved by means of light scattering and extinction effects using a single laser beam to cover a size range of 0.8 to 275 microns diameter and a speed range of 0.2 to 20 meters/second. The LPS system was designed to operate in the high-vacuum environment of a space simulation chamber with cold shroud temperatures ranging from 77 to 300 K.

Solar Pumped Solid State Lasers for Space Solar Power: Experimental Path

Science.gov (United States)

Fork, Richard L.; Carrington, Connie K.; Walker, Wesley W.; Cole, Spencer T.; Green, Jason J. A.; Laycock, Rustin L.

2003-01-01

We outline an experimentally based strategy designed to lead to solar pumped solid state laser oscillators useful for space solar power. Our method involves solar pumping a novel solid state gain element specifically designed to provide efficient conversion of sunlight in space to coherent laser light. Kilowatt and higher average power is sought from each gain element. Multiple such modular gain elements can be used to accumulate total average power of interest for power beaming in space, e.g., 100 kilowatts and more. Where desirable the high average power can also be produced as a train of pulses having high peak power (e.g., greater than 10(exp 10 watts). The modular nature of the basic gain element supports an experimental strategy in which the core technology can be validated by experiments on a single gain element. We propose to do this experimental validation both in terrestrial locations and also on a smaller scale in space. We describe a terrestrial experiment that includes diagnostics and the option of locating the laser beam path in vacuum environment. We describe a space based experiment designed to be compatible with the Japanese Experimental Module (JEM) on the International Space Station (ISS). We anticipate the gain elements will be based on low temperature (approx. 100 degrees Kelvin) operation of high thermal conductivity (k approx. 100 W/cm-K) diamond and sapphire (k approx. 4 W/cm-K). The basic gain element will be formed by sequences of thin alternating layers of diamond and Ti:sapphire with special attention given to the material interfaces. We anticipate this strategy will lead to a particularly simple, robust, and easily maintained low mass modelocked multi-element laser oscillator useful for space solar power.

The immune system in space, including Earth-based benefits of space-based research.

Science.gov (United States)

Sonnenfeld, Gerald

2005-08-01

Exposure to space flight conditions has been shown to result in alterations in immune responses. Changes in immune responses of humans and experimental animals have been shown to be altered during and after space flight of humans and experimental animals or cell cultures of lymphoid cells. Exposure of subjects to ground-based models of space flight conditions, such as hindlimb unloading of rodents or chronic bed rest of humans, has also resulted in changes in the immune system. The relationship of these changes to compromised resistance to infection or tumors in space flight has not been fully established, but results from model systems suggest that alterations in the immune system that occur in space flight conditions may be related to decreases in resistance to infection. The establishment of such a relationship could lead to the development of countermeasures that could prevent or ameliorate any compromises in resistance to infection resulting from exposure to space flight conditions. An understanding of the mechanisms of space flight conditions effects on the immune response and development of countermeasures to prevent them could contribute to the development of treatments for compromised immunity on earth.

An improved three-dimensional non-scanning laser imaging system based on digital micromirror device

Science.gov (United States)

Xia, Wenze; Han, Shaokun; Lei, Jieyu; Zhai, Yu; Timofeev, Alexander N.

2018-01-01

Nowadays, there are two main methods to realize three-dimensional non-scanning laser imaging detection, which are detection method based on APD and detection method based on Streak Tube. However, the detection method based on APD possesses some disadvantages, such as small number of pixels, big pixel interval and complex supporting circuit. The detection method based on Streak Tube possesses some disadvantages, such as big volume, bad reliability and high cost. In order to resolve the above questions, this paper proposes an improved three-dimensional non-scanning laser imaging system based on Digital Micromirror Device. In this imaging system, accurate control of laser beams and compact design of imaging structure are realized by several quarter-wave plates and a polarizing beam splitter. The remapping fiber optics is used to sample the image plane of receiving optical lens, and transform the image into line light resource, which can realize the non-scanning imaging principle. The Digital Micromirror Device is used to convert laser pulses from temporal domain to spatial domain. The CCD with strong sensitivity is used to detect the final reflected laser pulses. In this paper, we also use an algorithm which is used to simulate this improved laser imaging system. In the last, the simulated imaging experiment demonstrates that this improved laser imaging system can realize three-dimensional non-scanning laser imaging detection.

Deep Space Habitat Configurations Based on International Space Station Systems

Science.gov (United States)

Smitherman, David; Russell, Tiffany; Baysinger, Mike; Capizzo, Pete; Fabisinski, Leo; Griffin, Brand; Hornsby, Linda; Maples, Dauphne; Miernik, Janie

2012-01-01

A Deep Space Habitat (DSH) is the crew habitation module designed for long duration missions. Although humans have lived in space for many years, there has never been a habitat beyond low-Earth-orbit. As part of the Advanced Exploration Systems (AES) Habitation Project, a study was conducted to develop weightless habitat configurations using systems based on International Space Station (ISS) designs. Two mission sizes are described for a 4-crew 60-day mission, and a 4-crew 500-day mission using standard Node, Lab, and Multi-Purpose Logistics Module (MPLM) sized elements, and ISS derived habitation systems. These durations were selected to explore the lower and upper bound for the exploration missions under consideration including a range of excursions within the Earth-Moon vicinity, near earth asteroids, and Mars orbit. Current methods for sizing the mass and volume for habitats are based on mathematical models that assume the construction of a new single volume habitat. In contrast to that approach, this study explored the use of ISS designs based on existing hardware where available and construction of new hardware based on ISS designs where appropriate. Findings included a very robust design that could be reused if the DSH were assembled and based at the ISS and a transportation system were provided for its return after each mission. Mass estimates were found to be higher than mathematical models due primarily to the use of multiple ISS modules instead of one new large module, but the maturity of the designs using flight qualified systems have potential for improved cost, schedule, and risk benefits.

Calibration method for a vision guiding-based laser-tracking measurement system

International Nuclear Information System (INIS)

Shao, Mingwei; Wei, Zhenzhong; Hu, Mengjie; Zhang, Guangjun

2015-01-01

Laser-tracking measurement systems (laser trackers) based on a vision-guiding device are widely used in industrial fields, and their calibration is important. As conventional methods typically have many disadvantages, such as difficult machining of the target and overdependence on the retroreflector, a novel calibration method is presented in this paper. The retroreflector, which is necessary in the normal calibration method, is unnecessary in our approach. As the laser beam is linear, points on the beam can be obtained with the help of a normal planar target. In this way, we can determine the function of a laser beam under the camera coordinate system, while its corresponding function under the laser-tracker coordinate system can be obtained from the encoder of the laser tracker. Clearly, when several groups of functions are confirmed, the rotation matrix can be solved from the direction vectors of the laser beams in different coordinate systems. As the intersection of the laser beams is the origin of the laser-tracker coordinate system, the translation matrix can also be determined. Our proposed method not only achieves the calibration of a single laser-tracking measurement system but also provides a reference for the calibration of a multistation system. Simulations to evaluate the effects of some critical factors were conducted. These simulations show the robustness and accuracy of our method. In real experiments, the root mean square error of the calibration result reached 1.46 mm within a range of 10 m, even though the vision-guiding device focuses on a point approximately 5 m away from the origin of its coordinate system, with a field of view of approximately 200 mm  ×  200 mm. (paper)

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.

Narrow linewidth diode laser modules for quantum optical sensor applications in the field and in space

Science.gov (United States)

Wicht, A.; Bawamia, A.; Krüger, M.; Kürbis, Ch.; Schiemangk, M.; Smol, R.; Peters, A.; Tränkle, G.

2017-02-01

We present the status of our efforts to develop very compact and robust diode laser modules specifically suited for quantum optics experiments in the field and in space. The paper describes why hybrid micro-integration and GaAs-diode laser technology is best suited to meet the needs of such applications. The electro-optical performance achieved with hybrid micro-integrated, medium linewidth, high power distributed-feedback master-oscillator-power-amplifier modules and with medium power, narrow linewidth extended cavity diode lasers emitting at 767 nm and 780 nm are briefly described and the status of space relevant stress tests and space heritage is summarized. We also describe the performance of an ECDL operating at 1070 nm. Further, a novel and versatile technology platform is introduced that allows for integration of any type of laser system or electro-optical module that can be constructed from two GaAs chips. This facilitates, for the first time, hybrid micro-integration, e.g. of extended cavity diode laser master-oscillator-poweramplifier modules, of dual-stage optical amplifiers, or of lasers with integrated, chip-based phase modulator. As an example we describe the implementation of an ECDL-MOPA designed for experiments on ultra-cold rubidium and potassium atoms on board a sounding rocket and give basic performance parameters.

An expert systems application to space base data processing

Science.gov (United States)

Babb, Stephen M.

1988-01-01

The advent of space vehicles with their increased data requirements are reflected in the complexity of future telemetry systems. Space based operations with its immense operating costs will shift the burden of data processing and routine analysis from the space station to the Orbital Transfer Vehicle (OTV). A research and development project is described which addresses the real time onboard data processing tasks associated with a space based vehicle, specifically focusing on an implementation of an expert system.

Adhesive Bonding for Optical Metrology Systems in Space Applications

International Nuclear Information System (INIS)

Gohlke, Martin; Schuldt, Thilo; Braxmaier, Claus; Döringshoff, Klaus; Peters, Achim; Johann, Ulrich; Weise, Dennis

2015-01-01

Laser based metrology systems become more and more attractive for space applications and are the core elements of planned missions such as LISA (NGO, eLISA) or NGGM where laser interferometry is used for distance measurements between satellites. The GRACE-FO mission will for the first time demonstrate a Laser Ranging Instrument (LRI) in space, starting 2017. Laser based metrology also includes optical clocks/references, either as ultra-stable light source for high sensitivity interferometry or as scientific payload e.g. proposed in fundamental physics missions such as mSTAR (mini SpaceTime Asymmetry Research), a mission dedicated to perform a Kennedy-Thorndike experiment on a satellite in a low-Earth orbit. To enable the use of existing optical laboratory setups, optimization with respect to power consumption, weight and dimensions is necessary. At the same time the thermal and structural stability must be increased. Over the last few years we investigated adhesive bonding of optical components to thermally highly stable glass ceramics as an easy-to-handle assembly integration technology. Several setups were implemented and tested for potential later use in space applications. We realized a heterodyne LISA related interferometer with demonstrated noise levels in the pm-range for translation measurement and nano-radiant-range for tilt measurements and two iodine frequency references on Elegant Breadboard (EBB) and Engineering Model (EM) level with frequency stabilities in the 10 -15 range for longer integration times. The EM setup was thermally cycled and vibration tested. (paper)

Research on optic antenna of space laser communication networking

Science.gov (United States)

Meng, Li-Xin; Li, Long; Zhang, Li-zhong; Zhao, Shan-shan; Jiang, Hui-lin

2013-08-01

With the highlights of the high transmission rate, large capacity, strong anti-interference and anti-capture ability, good security and small light, space laser communication becomes an important hotspot. At present, the focus of research of the laser communication system is point to point communication structure. However, from the application point of view, both the realization of space laser communication among multiple points and the establishment of the information transmission network can really have the practical value. Aiming at the problem of space laser communication network, this article puts forward the general idea about optical antenna to achieve multiple tracking goals at the same time. Through the analysis of the optical antenna, and the comparing of the current commonly used mirror driving mechanism, a new mirror driving mechanism is designed. The azimuth motion, containing circular grating feedback, is driven by torque motor，voice coil motor of fan produces pitch motion that has fan-shaped grating feedback, so that compression of the structure size to improve the efficiency of the reflector assembly. Through the establishment of the driving mechanism and the kinematic model of 3D entity, the relationship between the single drive azimuth and pitch angle following the angle of incident light is explained. The biggest ideal view area affecting the optical antenna is obtained by the simulation analysis of the kinematics model using MATLAB. The several factors of field overlap area and blind area offers a theoretical basis for structure optimization and control system for the subsequent optical antenna design.

Field-Testing of an Active Laser Tracking System

Science.gov (United States)

Markov, V.; Khiznyak, A.; Woll, D.; Liu, S.

Comprehensive space surveillance demands a more accurate technique in tracking multi-dimensional state vector (3D coordinate, velocity, vibration, etc.) of the space objects. RF radiometric techniques typically can not provide the needed accuracy, while passive optical (and laser) tracking systems can provide distance to the object and its angular position, but not a direct reading of velocity, the parameter of primary importance for space object tracking and characterization. Addressing this problem with active optical tracking techniques is challenging because of the great distances involved, the high velocity of the satellites, and the optical aberrations induced by the atmosphere. We have proposed a phase conjugation based laser tracking concept, and accomplished the first version of design and engineering of a prototype for an Active Laser Tracking System (ALTS). In its current state the ALTS is capable to demonstrate the very basics operational principles of the proposed active tracking technique. We then performed a number of experiments to prove operational capabilities of this prototype both at MetroLaser's lab environment and at Edwards AFB Test Range. In its current architecture the ALTS is comprised of two laser cavities, Master and Slave that are coupled through a Phase Conjugate Mirror (PCM) formed in a non-linear medium (NLM) set at Master laser cavity. By pumping NLM and forming PCM, Master laser establishes the cavities coupling mode and injects the photons in the slave cavity. It is essential that the specific features of the PCM not only serve to couple ALTS cavities, but also serves to compensate optical aberrations of the ALTS (gain media and optical elements of the laser resonator). Due to its ability to compensate optical aberrations, phase conjugate resonators are capable of sustaining oscillation with a remote target as an output coupler. The entire system comprises of several modules, including a laser, emitting/receiving telescope, gimbal

Evaluation of 2.1μm DFB lasers for space applications

Science.gov (United States)

Barbero, J.; López, D.; Esquivias, I.; Tijero, J. M. G.; Fischer, M.; Roessner, K.; Koeth, J.; Zahir, M.

2017-11-01

This paper presents the results obtained in the frame of an ESA-funded project called "Screening and Preevaluation of Shortwave Infrared Laser Diode for Space Application" with the objective of verifying the maturity of state of the art SWIR DFB lasers at 2.1μm to be used for space applications (mainly based on the occultation measurement principle and spectroscopy). The paper focus on the functional and environmental evaluation test plan. It includes high precision characterization, mechanical test (vibration and SRS shocks), thermal cycling, gamma and proton radiation tests, life test and some details of the Destructive Physical Analysis performed. The electro-optical characterization includes measurements of the tuning capabilities of the laser both by current and by temperature, the wavelength stability and the optical power versus laser current.

Coherent Laser Radar Metrology System for Large Scale Optical Systems, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — A new type of laser radar metrology inspection system is proposed that incorporates a novel, dual laser coherent detection scheme capable of eliminating both...

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.

The laser calibration system for the STACEE ground-based gamma ray detector

CERN Document Server

Hanna, D

2002-01-01

We describe the design and performance of the laser system used for calibration monitoring of components of the STACEE detector. STACEE is a ground based gamma ray detector which uses the heliostats of a solar power facility to collect and focus Cherenkov light onto a system of secondary optics and photomultiplier tubes. To monitor the gain and check the linearity and timing properties of the phototubes and associated electronics, a system based on a dye laser, neutral density filters and optical fibres has been developed. In this paper we describe the system and present some results from initial tests made with it.

Multipurpose terahertz quantum cascade laser based system for industrial, environmental and meteorological applications

International Nuclear Information System (INIS)

Taslakov, M; Simeonov, V; Bergh, H van den

2008-01-01

A portable system, based on a pulsed quantum cascade laser (QCL) is developed. The QCL operates at near to ambient temperature in a pulsed mode with relatively long pulse duration in the range of 200 - 500 ns. The system design is flexible, allowing its use for a number of open path or cell-internal applications. Due to the so called fingerprint spectral region, high haze and turbulence immunity and low beam divergence, this system can be used in various applications. The first group includes environmental monitoring of a number of trace gases as CH 4 , NH 3 , CO, O 3 , CO 2 , HNO 3 , hydrocarbons and many others. The meteorological applications include measuring the average humidity and temperature. Industrial surveillance control is another important application. Remote measurement of some physical parameters, as temperature or pressure, as well as for interferometric measurements are also possible. Space resolved study of air turbulence even in fog is another promising application. Security, speed control, open path data transfer and remote readout of information are but a few other real applications of our QCL based portable system

Propulsion Utilizing Laser-Driven Ponderomotive Fields for Deep-Space Missions

International Nuclear Information System (INIS)

Williams, George J.; Gilland, James H.

2009-01-01

The generation of large amplitude electric fields in plasmas by high-power lasers has been studied for several years in the context of high-energy particle acceleration. Fields on the order of GeV/m are generated in the plasma wake of the laser by non-linear ponderomotive forces. The laser fields generate longitudinal and translational electron plasma waves with phase velocities close to the speed of light. These fields and velocities offer the potential to revolutionize spacecraft propulsion, leading to extended deep space robotic probes. Based on these initial calculations, plasma acceleration by means of laser-induced ponderomotive forces appears to offer significant potential for spacecraft propulsion. Relatively high-efficiencies appear possible with proper beam conditioning, resulting in an order of magnitude more thrust than alternative concepts for high I SP (>10 5 s) and elimination of the primary life-limiting erosion phenomena associated with conventional electric propulsion systems. Ponderomotive propulsion readily lends itself to beamed power which might overcome some of the constraints of power-limited propulsion concepts. A preliminary assessment of the impact of these propulsion systems for several promising configurations on mission architectures has been conducted. Emphasizing interstellar and interstellar-precursor applications, performance and technical requirements are identified for a number of missions. The use of in-situ plasma and gas for propellant is evaluated as well.

Tests of gravity with future space-based experiments

Science.gov (United States)

Sakstein, Jeremy

2018-03-01

Future space-based tests of relativistic gravitation—laser ranging to Phobos, accelerometers in orbit, and optical networks surrounding Earth—will constrain the theory of gravity with unprecedented precision by testing the inverse-square law, the strong and weak equivalence principles, and the deflection and time delay of light by massive bodies. In this paper, we estimate the bounds that could be obtained on alternative gravity theories that use screening mechanisms to suppress deviations from general relativity in the Solar System: chameleon, symmetron, and Galileon models. We find that space-based tests of the parametrized post-Newtonian parameter γ will constrain chameleon and symmetron theories to new levels, and that tests of the inverse-square law using laser ranging to Phobos will provide the most stringent constraints on Galileon theories to date. We end by discussing the potential for constraining these theories using upcoming tests of the weak equivalence principle, and conclude that further theoretical modeling is required in order to fully utilize the data.

WSN-Based Space Charge Density Measurement System.

Science.gov (United States)

Deng, Dawei; Yuan, Haiwen; Lv, Jianxun; Ju, Yong

2017-01-01

It is generally acknowledged that high voltage direct current (HVDC) transmission line endures the drawback of large area, because of which the utilization of cable for space charge density monitoring system is of inconvenience. Compared with the traditional communication network, wireless sensor network (WSN) shows advantages in small volume, high flexibility and strong self-organization, thereby presenting great potential in solving the problem. Additionally, WSN is more suitable for the construction of distributed space charge density monitoring system as it has longer distance and higher mobility. A distributed wireless system is designed for collecting and monitoring the space charge density under HVDC transmission lines, which has been widely applied in both Chinese state grid HVDC test base and power transmission projects. Experimental results of the measuring system demonstrated its adaptability in the complex electromagnetic environment under the transmission lines and the ability in realizing accurate, flexible, and stable demands for the measurement of space charge density.

Laser Guidestar Satellite for Ground-based Adaptive Optics Imaging of Geosynchronous Satellites and Astronomical Targets

Science.gov (United States)

Marlow, W. A.; Cahoy, K.; Males, J.; Carlton, A.; Yoon, H.

2015-12-01

Real-time observation and monitoring of geostationary (GEO) satellites with ground-based imaging systems would be an attractive alternative to fielding high cost, long lead, space-based imagers, but ground-based observations are inherently limited by atmospheric turbulence. Adaptive optics (AO) systems are used to help ground telescopes achieve diffraction-limited seeing. AO systems have historically relied on the use of bright natural guide stars or laser guide stars projected on a layer of the upper atmosphere by ground laser systems. There are several challenges with this approach such as the sidereal motion of GEO objects relative to natural guide stars and limitations of ground-based laser guide stars; they cannot be used to correct tip-tilt, they are not point sources, and have finite angular sizes when detected at the receiver. There is a difference between the wavefront error measured using the guide star compared with the target due to cone effect, which also makes it difficult to use a distributed aperture system with a larger baseline to improve resolution. Inspired by previous concepts proposed by A.H. Greenaway, we present using a space-based laser guide starprojected from a satellite orbiting the Earth. We show that a nanosatellite-based guide star system meets the needs for imaging GEO objects using a low power laser even from 36,000 km altitude. Satellite guide star (SGS) systemswould be well above atmospheric turbulence and could provide a small angular size reference source. CubeSatsoffer inexpensive, frequent access to space at a fraction of the cost of traditional systems, and are now being deployed to geostationary orbits and on interplanetary trajectories. The fundamental CubeSat bus unit of 10 cm cubed can be combined in multiple units and offers a common form factor allowing for easy integration as secondary payloads on traditional launches and rapid testing of new technologies on-orbit. We describe a 6U CubeSat SGS measuring 10 cm x 20 cm x

A Laser-Based Measuring System for Online Quality Control of Car Engine Block

Directory of Open Access Journals (Sweden)

Xing-Qiang Li

2016-11-01

Full Text Available For online quality control of car engine production, pneumatic measurement instrument plays an unshakeable role in measuring diameters inside engine block because of its portability and high-accuracy. To the limitation of its measuring principle, however, the working space between the pneumatic device and measured surface is too small to require manual operation. This lowers the measuring efficiency and becomes an obstacle to perform automatic measurement. In this article, a high-speed, automatic measuring system is proposed to take the place of pneumatic devices by using a laser-based measuring unit. The measuring unit is considered as a set of several measuring modules, where each of them acts like a single bore gauge and is made of four laser triangulation sensors (LTSs, which are installed on different positions and in opposite directions. The spatial relationship among these LTSs was calibrated before measurements. Sampling points from measured shaft holes can be collected by the measuring unit. A unified mathematical model was established for both calibration and measurement. Based on the established model, the relative pose between the measuring unit and measured workpiece does not impact the measuring accuracy. This frees the measuring unit from accurate positioning or adjustment, and makes it possible to realize fast and automatic measurement. The proposed system and method were finally validated by experiments.

The Space Laser Business Model

Science.gov (United States)

2005-01-01

Creating long-duration, high-powered lasers, for satellites, that can withstand the type of optical misalignment and damage dished out by the unforgiving environment of space, is work that is unique to NASA. It is complicated, specific work, where each step forward is into uncharted territory. In the 1990s, as this technology was first being created, NASA gave free reign to a group of "laser jocks" to develop their own business model and supply the Space Agency with the technology it needed. It was still to be a part of NASA as a division of Goddard Space Flight Center, but would operate independently out of a remote office. The idea for this satellite laboratory was based on the Skunk Works concept at Lockheed Martin Corporation. Formerly known as the Lockheed Corporation, in 1943, the aerospace firm, realizing that the type of advanced research it needed done could not be performed within the confines of a larger company, allowed a group of researchers and engineers to essentially run their own microbusiness without the corporate oversight. The Skunk Works project, in Burbank, California, produced America s first jet fighter, the world s most successful spy plane (U-2), the first 3-times-the-speed-of-sound surveillance aircraft, and the F-117A Nighthawk Stealth Fighter. Boeing followed suit with its Phantom Works, an advanced research and development branch of the company that operates independent of the larger unit and is responsible for a great deal of its most cutting-edge research. NASA s version of this advanced business model was the Space Lidar Technology Center (SLTC), just south of Goddard, in College Park, Maryland. Established in 1998 under a Cooperative Agreement between Goddard and the University of Maryland s A. James Clark School of Engineering, it was a high-tech laser shop where a small group of specialists, never more than 20 employees, worked all hours of the day and night to create the cutting- edge technology the Agency required of them. Drs

Level crossing statistics for optical beam wander in a turbulent atmosphere with applications to ground-to-space laser communications.

Science.gov (United States)

Yura, Harold T; Fields, Renny A

2011-06-20

Level crossing statistics is applied to the complex problem of atmospheric turbulence-induced beam wander for laser propagation from ground to space. A comprehensive estimate of the single-axis wander angle temporal autocorrelation function and the corresponding power spectrum is used to develop, for the first time to our knowledge, analytic expressions for the mean angular level crossing rate and the mean duration of such crossings. These results are based on an extension and generalization of a previous seminal analysis of the beam wander variance by Klyatskin and Kon. In the geometrical optics limit, we obtain an expression for the beam wander variance that is valid for both an arbitrarily shaped initial beam profile and transmitting aperture. It is shown that beam wander can disrupt bidirectional ground-to-space laser communication systems whose small apertures do not require adaptive optics to deliver uniform beams at their intended target receivers in space. The magnitude and rate of beam wander is estimated for turbulence profiles enveloping some practical laser communication deployment options and suggesting what level of beam wander effects must be mitigated to demonstrate effective bidirectional laser communication systems.

A New Remote Monitoring System Application in Laser Power Based on LabVIEW

Directory of Open Access Journals (Sweden)

Liu Gaoqiang

2016-01-01

Full Text Available In this paper, a new remote monitoring system based on LabVIEW was proposed to measure laser power automatically and remotely. This system consists of four basic components: an DH-JG2 optical power meter, a NI-USB 6008 data acquisition card, a personal computer (PC, and HP laserJet 1020 Plus printer. Since power output of laser is generally so unstable that abnormal work situation could not retroaction to inspectors right away, new system was designed to solve this problem. The detection system realized function of remote control by TCP protocol and mobile phone. Laser power curve that is measured by detection system demonstrated that the design has a good performance in real-time detection and operability.

Laser-based additive manufacturing of metals

CSIR Research Space (South Africa)

Kumar, S

2010-11-01

Full Text Available For making metallic products through Additive Manufacturing (AM) processes, laser-based systems play very significant roles. Laser-based processes such as Selective Laser Melting (SLM) and Laser Engineered Net Shaping (LENS) are dominating processes...

Compact variable rate laser for space application

Data.gov (United States)

National Aeronautics and Space Administration — We will focus on the development and test of high reliable, radiation tolerant, compact laser for planetary mission.  The laser will be able to operate at variable...

Fiber-Based Lasers as an Option for GRACE Follow-On Light Source

Science.gov (United States)

Camp, Jordan

2010-01-01

Fiber based lasers offer a number of attractive characteristics for space application: state of the art laser technology, leverage of design and reliability from the substantial investments of the telecon industry, and convenient redundancy of higher risk components through fiber splicing. At NASA/Goddard we are currently investigating three GFO fiber-based laser options: a fiber oscillator built in our laboratory; an effort to space qualify a commercial design that uses a proprietary high-gain fiber cavity; and the space qualification of a promising new commercial external cavity laser, notable for its low-mass, compact design. In my talk I will outline these efforts, and suggest that the GFO Project may soon have the option of a US laser vendor for its light source.

Laser propulsion for orbit transfer - Laser technology issues

Science.gov (United States)

Horvath, J. C.; Frisbee, R. H.

1985-01-01

Using reasonable near-term mission traffic models (1991-2000 being the assumed operational time of the system) and the most current unclassified laser and laser thruster information available, it was found that space-based laser propulsion orbit transfer vehicles (OTVs) can outperform the aerobraked chemical OTV over a 10-year life-cycle. The conservative traffic models used resulted in an optimum laser power of about 1 MW per laser. This is significantly lower than the power levels considered in other studies. Trip time was taken into account only to the extent that the system was sized to accomplish the mission schedule.

Applications of power beaming from space-based nuclear power stations. [Laser beaming to airplanes; microwave beaming to ground

Energy Technology Data Exchange (ETDEWEB)

Powell, J.R.; Botts, T.E.; Hertzberg, A.

1981-01-01

Power beaming from space-based reactor systems is examined using an advanced compact, lightweight Rotating Bed Reactor (RBR). Closed Brayton power conversion efficiencies in the range of 30 to 40% can be achieved with turbines, with reactor exit temperatures on the order of 2000/sup 0/K and a liquid drop radiator to reject heat at temperatures of approx. 500/sup 0/K. Higher RBR coolant temperatures (up to approx. 3000/sup 0/K) are possible, but gains in power conversion efficiency are minimal, due to lower expander efficiency (e.g., a MHD generator). Two power beaming applications are examined - laser beaming to airplanes and microwave beaming to fixed ground receivers. Use of the RBR greatly reduces system weight and cost, as compared to solar power sources. Payback times are a few years at present prices for power and airplane fuel.

Image-based tracking system for vibration measurement of a rotating object using a laser scanning vibrometer

Energy Technology Data Exchange (ETDEWEB)

Kim, Dongkyu, E-mail: akein@gist.ac.kr; Khalil, Hossam; Jo, Youngjoon; Park, Kyihwan, E-mail: khpark@gist.ac.kr [School of Mechatronics, Gwangju Institute of Science and Technology, Buk-gu, Gwangju, South Korea, 500-712 (Korea, Republic of)

2016-06-28

An image-based tracking system using laser scanning vibrometer is developed for vibration measurement of a rotating object. The proposed system unlike a conventional one can be used where the position or velocity sensor such as an encoder cannot be attached to an object. An image processing algorithm is introduced to detect a landmark and laser beam based on their colors. Then, through using feedback control system, the laser beam can track a rotating object.

Development of Laser Based Remote Sensing System for Inner-Concrete Defects

Science.gov (United States)

Shimada, Yoshinori; Kotyaev, Oleg

Laser-based remote sensing using a vibration detection system has been developed using a photorefractive crystal to reduce the effect of concrete surface-roughness. An electric field was applied to the crystal and the reference beam was phase shifted to increase the detection efficiency (DE). The DE increased by factor of 8.5 times compared to that when no voltage and no phase shifting were applied. Vibration from concrete defects can be detected at a distance of 5 m from the system. A vibration-canceling system has also developed that appears to be promising for canceling vibrations between the laser system and the concrete. Finally, we have constructed a prototype system that can be transported in a small truck.

Some characteristics of isotopic separation laser systems

International Nuclear Information System (INIS)

Pochon, E.

1988-01-01

The principle of Laser Isotope Separation (LIS) is simple and based on either selective electronic photoexcitation and photoionization of atomic vapor, or selective vibrational photoexcitation and photodissociation of molecules in the gas phase. These processes, respectively called SILVA (AVLIS) and SILMO (MLIS) in France, both use specific laser systems with wavelengths spanning from infrared to ultraviolet. This article describes briefly some of the characteristics of a SILVA laser system. Following a three-step process, a SILVA laser system is based on dye copper vapor lasers. The pulse dye lasers provide the tunable laser light and are optically pumped by copper vapor laser operating at high repetition rates. In order to meet plant laser system requirements, the main improvements under way relate to copper vapor laser devices the power capability, efficiency, reliability and lifetime of which have to be increased. 1 fig

Solar pumped laser technology options for space power transmission

Science.gov (United States)

Conway, E. J.

1986-01-01

An overview of long-range options for in-space laser power transmission is presented. The focus is on the new technology and research status of solar-pumped lasers and their solar concentration needs. The laser options include gas photodissociation lasers, optically-pumped solid-state lasers, and blackbody-pumped transfer lasers. The paper concludes with a summary of current research thrusts.

Lidar and Laser Technology for NASA’S Cloud-Aerosol Transport System (CATS Payload on The International Space Station (JEM-EF

Directory of Open Access Journals (Sweden)

Storm Mark

2016-01-01

Full Text Available This paper describes the ISS lidar technology provided by Fibertek, Inc. in support of the NASA GSFC CATS mission and provides an assessment of the in-flight systems performance and lessons learned. During February the systems successfully operated in space for more than 300 hours using 25 W average power lasers and photon counting of aerosol atmospheric returns.

Laser cutting of irregular shape object based on stereo vision laser galvanometric scanning system

Science.gov (United States)

Qi, Li; Zhang, Yixin; Wang, Shun; Tang, Zhiqiang; Yang, Huan; Zhang, Xuping

2015-05-01

Irregular shape objects with different 3-dimensional (3D) appearances are difficult to be shaped into customized uniform pattern by current laser machining approaches. A laser galvanometric scanning system (LGS) could be a potential candidate since it can easily achieve path-adjustable laser shaping. However, without knowing the actual 3D topography of the object, the processing result may still suffer from 3D shape distortion. It is desirable to have a versatile auxiliary tool that is capable of generating 3D-adjusted laser processing path by measuring the 3D geometry of those irregular shape objects. This paper proposed the stereo vision laser galvanometric scanning system (SLGS), which takes the advantages of both the stereo vision solution and conventional LGS system. The 3D geometry of the object obtained by the stereo cameras is used to guide the scanning galvanometers for 3D-shape-adjusted laser processing. In order to achieve precise visual-servoed laser fabrication, these two independent components are integrated through a system calibration method using plastic thin film target. The flexibility of SLGS has been experimentally demonstrated by cutting duck feathers for badminton shuttle manufacture.

Theory and experiments in model-based space system anomaly management

Science.gov (United States)

Kitts, Christopher Adam

This research program consists of an experimental study of model-based reasoning methods for detecting, diagnosing and resolving anomalies that occur when operating a comprehensive space system. Using a first principles approach, several extensions were made to the existing field of model-based fault detection and diagnosis in order to develop a general theory of model-based anomaly management. Based on this theory, a suite of algorithms were developed and computationally implemented in order to detect, diagnose and identify resolutions for anomalous conditions occurring within an engineering system. The theory and software suite were experimentally verified and validated in the context of a simple but comprehensive, student-developed, end-to-end space system, which was developed specifically to support such demonstrations. This space system consisted of the Sapphire microsatellite which was launched in 2001, several geographically distributed and Internet-enabled communication ground stations, and a centralized mission control complex located in the Space Technology Center in the NASA Ames Research Park. Results of both ground-based and on-board experiments demonstrate the speed, accuracy, and value of the algorithms compared to human operators, and they highlight future improvements required to mature this technology.

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.

High energy, single frequency, tunable laser source operating in burst mode for space based lidar applications

Science.gov (United States)

Cosentino, Alberto; Mondello, Alessia; Sapia, Adalberto; D'Ottavi, Alessandro; Brotini, Mauro; Gironi, Gianna; Suetta, Enrico

2017-11-01

This paper describes energetic, spatial, temporal and spectral characterization measurements of the Engineering Qualification Model (EQM) of the Laser Transmitter Assembly (TXA) used in the ALADIN instrument currently under development for the ESA ADM-AEOLUS mission (EADS Astrium as prime contractor for the satellite and the instrument). The EQM is equivalent to the Flight Model, with the exception of some engineering grade components. The Laser Transmitter Assembly, based on a diode pumped tripled Nd:YAG laser, is used to generate laser pulses at a nominal wavelength of 355 nm. This laser is operated in burst mode, with a pulse repetition cycle of 100 Hz during bursts. It is capable to operate in Single Longitudinal Mode and to be tuned over 25 GHz range. An internal "network" of sensors has been implemented inside the laser architecture to allow "in flight" monitoring of transmitter. Energy in excess of 100 mJ, with a spatial beam quality factor (M2) lower than 3, a spectral linewidth less than 50 MHz with a frequency stability better than 4 MHz on short term period have been measured on the EQM. Most of the obtained results are well within the expected values and match the Instrument requirements. They constitute an important achievement, showing the absence of major critical areas in terms of performance and the capability to obtain them in a rugged and compact structure suitable for space applications. The EQM will be submitted in the near future to an Environmental test campaign.

Laser Megajoule synchronization system

International Nuclear Information System (INIS)

Luttmann, M.; Pastor, J.F; Drouet, V.; Prat, M.; Raimbourg, J.; Adolf, A.

2011-01-01

This paper describes the synchronisation system under development on the Laser Megajoule (LMJ) in order to synchronize the laser quads on the target to better than 40 ps rms. Our architecture is based on a Timing System (TS) which delivers trigger signals with jitter down to 15 ps rms coupled with an ultra precision timing system with 5 ps rms jitter. In addition to TS, a sensor placed at the target chamber center measures the arrival times of the 3 omega nano joule laser pulses generated by front end shots. (authors)

Efficient, space-based, PM 100W thulium fiber laser for pumping Q-switched 2μm Ho:YLF for global winds and carbon dioxide lidar

Science.gov (United States)

Engin, Doruk; Mathason, Brian; Storm, Mark

2017-08-01

Global wind measurements are critically needed to improve and extend NOAA weather forecasting that impacts U.S. economic activity such as agriculture crop production, as well as hurricane forecasting, flooding, and FEMA disaster planning.1 NASA and the 2007 National Research Council (NRC) Earth Science Decadal Study have also identified global wind measurements as critical for global change research. NASA has conducted aircraft-based wind lidar measurements using 2 um Ho:YLF lasers, which has shown that robust wind measurements can be made. Fibertek designed and demonstrated a high-efficiency, 100 W average power continuous wave (CW) 1940 nm thulium (Tm)- doped fiber laser bread-board system meeting all requirements for a NASA Earth Science spaceflight 2 μm Ho:YLF pump laser. Our preliminary design shows that it is possible to package the laser for high-reliability spaceflight operation in an ultra-compact 2″x8″x14″ size and weight <8.5 lbs. A spaceflight 100 W polarization maintaining (PM) Tm laser provides a path to space for a pulsed, Q-switched 2 μm Ho:YLF laser with 30-80 mJ/pulse range at 100-200 Hz repletion rates.

Space nuclear power systems for extraterrestrial basing

International Nuclear Information System (INIS)

Lance, J.R.; Chi, J.W.H.

1989-01-01

Previous studies of nuclear and non-nuclear power systems for lunar bases are compared with recent studies by others. Power levels from tens of kW e for early base operation up to 2000 kW e for a self-sustaining base with a Closed Environment Life Support System (CELSS) are considered. Permanent lunar or Martian bases will require the use of multiple nuclear units connected to loads with a power transmission and distribution system analogous to earth-based electric utility systems. A methodology used for such systems is applied to the lunar base system to examine the effects of adding 100 kW e SP-100 class and/or larger nuclear units when a reliability criterion is imposed. The results show that resource and logistic burdens can be reduced by using 1000 kW e units early in the base growth scenario without compromising system reliability. Therefore, both technologies being developed in two current programs (SP-100 and NERVA Derivative Reactor (NDR) technology for space power) can be used effectively for extraterrestrial base power systems. Recent developments in NDR design that result in major reductions in reactor mass are also described. (author)

Laser Based Color Film Recorder System With GaAs Microlaser

Science.gov (United States)

Difrancesco, David J.

1989-07-01

In 1984 Pixar's research and development group built and applied to the motion-picture arts at Lucasfilm's ILM facility a three color laser based film scanner/recorder system. The digital film printer is capable of reading and writing 35mm film formats on a variety of film stocks. The system has been used in award-winning special-effects work, and has been operated in a normal production environment since that time. The primary objective was to develop a full color high resolution system, free from scan artifacts, enabling traditionally photographed motion-picture film to be inter-cut with digital raster image photography. Its use is applied to the art of blue-screen traveling-matte cinematography for motion pic-ture special effects. The system was designed using the Pixar Image Computer and conventional gas laser technology as the illumination source. This paper will discuss recent experimental work in the application of GaAs microlaser technology to a digital film printing system of the future.

Free-space laser communication technologies IV; Proceedings of the 4th Conference, Los Angeles, CA, Jan. 23, 24, 1992

Science.gov (United States)

Begley, David L. (Editor); Seery, Bernard D. (Editor)

1992-01-01

Papers included in this volume are grouped under topics of receivers; laser transmitters; components; system analysis, performance, and applications; and beam control (pointing, acquisition, and tracking). Papers are presented on an experimental determination of power penalty contributions in an optical Costas-type phase-locked loop receiver, a resonant laser receiver for free-space laser communications, a simple low-loss technique for frequency-locking lasers, direct phase modulation of laser diodes, and a silex beacon. Particular attention is given to experimental results on an optical array antenna for nonmechanical beam steering, a potassium Faraday anomalous dispersion optical filter, a 100-Mbps resonant cavity phase modulator for coherent optical communications, a numerical simulation of a 325-Mbit/s QPPM optical communication system, design options for an optical multiple-access data relay terminal, CCD-based optical tracking loop design trades, and an analysis of a spatial-tracking subsystem for optical communications.

Electronic Subsystems For Laser Communication System

Science.gov (United States)

Long, Catherine; Maruschak, John; Patschke, Robert; Powers, Michael

1992-01-01

Electronic subsystems of free-space laser communication system carry digital signals at 650 Mb/s over long distances. Applicable to general optical communications involving transfer of great quantities of data, and transmission and reception of video images of high definition.

Laser dimpling process parameters selection and optimization using surrogate-driven process capability space

Science.gov (United States)

Ozkat, Erkan Caner; Franciosa, Pasquale; Ceglarek, Dariusz

2017-08-01

Remote laser welding technology offers opportunities for high production throughput at a competitive cost. However, the remote laser welding process of zinc-coated sheet metal parts in lap joint configuration poses a challenge due to the difference between the melting temperature of the steel (∼1500 °C) and the vapourizing temperature of the zinc (∼907 °C). In fact, the zinc layer at the faying surface is vapourized and the vapour might be trapped within the melting pool leading to weld defects. Various solutions have been proposed to overcome this problem over the years. Among them, laser dimpling has been adopted by manufacturers because of its flexibility and effectiveness along with its cost advantages. In essence, the dimple works as a spacer between the two sheets in lap joint and allows the zinc vapour escape during welding process, thereby preventing weld defects. However, there is a lack of comprehensive characterization of dimpling process for effective implementation in real manufacturing system taking into consideration inherent changes in variability of process parameters. This paper introduces a methodology to develop (i) surrogate model for dimpling process characterization considering multiple-inputs (i.e. key control characteristics) and multiple-outputs (i.e. key performance indicators) system by conducting physical experimentation and using multivariate adaptive regression splines; (ii) process capability space (Cp-Space) based on the developed surrogate model that allows the estimation of a desired process fallout rate in the case of violation of process requirements in the presence of stochastic variation; and, (iii) selection and optimization of the process parameters based on the process capability space. The proposed methodology provides a unique capability to: (i) simulate the effect of process variation as generated by manufacturing process; (ii) model quality requirements with multiple and coupled quality requirements; and (iii

High speed real-time wavefront processing system for a solid-state laser system

Science.gov (United States)

Liu, Yuan; Yang, Ping; Chen, Shanqiu; Ma, Lifang; Xu, Bing

2008-03-01

A high speed real-time wavefront processing system for a solid-state laser beam cleanup system has been built. This system consists of a core2 Industrial PC (IPC) using Linux and real-time Linux (RT-Linux) operation system (OS), a PCI image grabber, a D/A card. More often than not, the phase aberrations of the output beam from solid-state lasers vary fast with intracavity thermal effects and environmental influence. To compensate the phase aberrations of solid-state lasers successfully, a high speed real-time wavefront processing system is presented. Compared to former systems, this system can improve the speed efficiently. In the new system, the acquisition of image data, the output of control voltage data and the implementation of reconstructor control algorithm are treated as real-time tasks in kernel-space, the display of wavefront information and man-machine conversation are treated as non real-time tasks in user-space. The parallel processing of real-time tasks in Symmetric Multi Processors (SMP) mode is the main strategy of improving the speed. In this paper, the performance and efficiency of this wavefront processing system are analyzed. The opened-loop experimental results show that the sampling frequency of this system is up to 3300Hz, and this system can well deal with phase aberrations from solid-state lasers.

STMD Laser Lifetest Program Space Gradiometer

Data.gov (United States)

National Aeronautics and Space Administration — Design and initiate lifetest activities on laser transmitter for the Cold Atom Gravity Gradiometer (CAGG) with funding from NASA STMD.This proposed task is to...

Semiconductor-based narrow-line and high-brilliance 193-nm laser system for industrial applications

Science.gov (United States)

Opalevs, D.; Scholz, M.; Stuhler, J.; Gilfert, C.; Liu, L. J.; Wang, X. Y.; Vetter, A.; Kirner, R.; Scharf, T.; Noell, W.; Rockstuhl, C.; Li, R. K.; Chen, C. T.; Voelkel, R.; Leisching, P.

2018-02-01

We present a novel industrial-grade prototype version of a continuous-wave 193 nm laser system entirely based on solid state pump laser technology. Deep-ultraviolet emission is realized by frequency-quadrupling an amplified diode laser and up to 20 mW of optical power were generated using the nonlinear crystal KBBF. We demonstrate the lifetime of the laser system for different output power levels and environmental conditions. The high stability of our setup was proven in > 500 h measurements on a single spot, a crystal shifter multiplies the lifetime to match industrial requirements. This laser improves the relative intensity noise, brilliance, wall-plug efficiency and maintenance cost significantly. We discuss first lithographic experiments making use of this improvement in photon efficiency.

Yb:YAG Lasers for Space Based Remote Sensing

Science.gov (United States)

Ewing, J.J.; Fan, T. Y.

1998-01-01

Diode pumped solid state lasers will play a prominent role in future remote sensing missions because of their intrinsic high efficiency and low mass. Applications including altimetry, cloud and aerosol measurement, wind velocity measurement by both coherent and incoherent methods, and species measurements, with appropriate frequency converters, all will benefit from a diode pumped primary laser. To date the "gold standard" diode pumped Nd laser has been the laser of choice for most of these concepts. This paper discusses an alternate 1 micron laser, the YB:YAG laser, and its potential relevance for lidar applications. Conceptual design analysis and, to the extent possible at the time of the conference, preliminary experimental data on the performance of a bread board YB:YAG oscillator will be presented. The paper centers on application of YB:YAG for altimetry, but extension to other applications will be discussed.

The laser-based calibration system of delta spectrometer

Energy Technology Data Exchange (ETDEWEB)

Malakhov, A.I. [Veksler and Baldin Laboratory of High Energies, JINR, Dubna (Russian Federation); Anisimov, Yu.S. [Veksler and Baldin Laboratory of High Energies, JINR, Dubna (Russian Federation); Gmuca, S. [Inst. of Physics, SAS, Bratislava (Slovakia); Kizka, V.A. [Veksler and Baldin Laboratory of High Energies, JINR, Dubna (Russian Federation); Kliman, J. [Veksler and Baldin Laboratory of High Energies, JINR, Dubna (Russian Federation); Inst. of Physics, SAS, Bratislava (Slovakia); Krasnov, V.A. [Veksler and Baldin Laboratory of High Energies, JINR, Dubna (Russian Federation); Kurepin, A.B. [Inst. for Nuclear Research RAS, Moscow (Russian Federation); Kuznetsov, S.N. [Veksler and Baldin Laboratory of High Energies, JINR, Dubna (Russian Federation); Livanov, A.N. [Veksler and Baldin Laboratory of High Energies, JINR, Dubna (Russian Federation); Matousek, V. [Inst. of Physics, SAS, Bratislava (Slovakia); Morhac, M. [Inst. of Physics, SAS, Bratislava (Slovakia)]. E-mail: Miroslav.Morhac@savba.sk; Turzo, I. [Inst. of Physics, SAS, Bratislava (Slovakia)

2006-10-15

We present a report on a laser calibration system of DELTA spectrometer that has been designed and developed in the Laboratory of High Energies, JINR, Dubna. The system is intended for monitoring and continuous stabilization of the outputs of the detectors of the spectrometer. The UV nitrogen pulse laser along with optical filters, collection of optical fibers and plastic scintillators serving for conversion of UV light pulses to longer wavelength and for diffusion of the light beam to illuminate 300 photomultipliers are used. We stabilize the positions of laser peaks by corrections of high voltages of the corresponding photomultipliers. The proposed system allows one to accomplish the stabilization during the experiment with the use of the same electronics. The control software together with the first results from test runs are described as well.

Research of narrow pulse width, high repetition rate, high output power fiber lasers for deep space exploration

Science.gov (United States)

Tang, Yan-feng; Li, Hong-zuo; Wang, Yan; Hao, Zi-qiang; Xiao, Dong-Ya

2013-08-01

As human beings expand the research in unknown areas constantly, the deep space exploration has become a hot research topic all over the world. According to the long distance and large amount of information transmission characteristics of deep space exploration, the space laser communication is the preferred mode because it has the advantages of concentrated energy, good security, and large information capacity and interference immunity. In a variety of laser source, fibre-optical pulse laser has become an important communication source in deep space laser communication system because of its small size, light weight and large power. For fiber lasers, to solve the contradiction between the high repetition rate and the peak value power is an important scientific problem. General Q technology is difficult to obtain a shorter pulse widths, This paper presents a DFB semiconductor laser integrated with Electro-absorption modulator to realize the narrow pulse width, high repetition rate of the seed source, and then using a two-cascaded high gain fiber amplifier as amplification mean, to realize the fibre-optical pulse laser with pulse width 3ns, pulse frequency 200kHz and peak power 1kW. According to the space laser atmospheric transmission window, the wavelength selects for 1.06um. It is adopted that full fibre technology to make seed source and amplification, pumping source and amplification of free-space coupled into fiber-coupled way. It can overcome that fibre lasers are vulnerable to changes in external conditions such as vibration, temperature drift and other factors affect, improving long-term stability. The fiber lasers can be modulated by PPM mode, to realize high rate modulation, because of its peak power, high transmission rate, narrow pulse width, high frequency stability, all technical indexes meet the requirements of the exploration of deep space communication technology.

Laser Spot Detection Based on Reaction Diffusion.

Science.gov (United States)

Vázquez-Otero, Alejandro; Khikhlukha, Danila; Solano-Altamirano, J M; Dormido, Raquel; Duro, Natividad

2016-03-01

Center-location of a laser spot is a problem of interest when the laser is used for processing and performing measurements. Measurement quality depends on correctly determining the location of the laser spot. Hence, improving and proposing algorithms for the correct location of the spots are fundamental issues in laser-based measurements. In this paper we introduce a Reaction Diffusion (RD) system as the main computational framework for robustly finding laser spot centers. The method presented is compared with a conventional approach for locating laser spots, and the experimental results indicate that RD-based computation generates reliable and precise solutions. These results confirm the flexibility of the new computational paradigm based on RD systems for addressing problems that can be reduced to a set of geometric operations.

Non-destructive visualization of linear explosive-induced Pyroshock using phase arrayed laser-induced shock in a space launcher composite

International Nuclear Information System (INIS)

Jang, Jae Kyeong; Lee, Jung Ryul

2015-01-01

Separation mechanism of Space launch vehicles are used in various separation systems and pyrotechnic devices. The operation of these pyrotechnic devices generates Pyroshock that can cause failures in electronic components. The prediction of high frequency structural response, especially the shock response spectrum (SRS), is important. This paper presents a non-destructive visualization and simulation of linear explosive-induced Pyroshock using phase arrayed Laser-induced shock. The proposed method includes a laser shock test based on laser beam and filtering zone conditioning to predict the SRS of Pyroshock. A ballistic test based on linear explosive and non-contact Laser Doppler Vibrometers and a nondestructive Laser shock measurement using laser excitation and several PZT sensors, are performed using a carbon composite sandwich panel. The similarity of the SRS of the conditioned laser shock to that of the real explosive Pyroshock is evaluated with the Mean Acceleration Difference. The average of MADs over the two training points was 33.64%. And, MAD at verification point was improved to 31.99%. After that, experimentally found optimal conditions are applied to any arbitrary points in laser scanning area. Finally, it is shown that linear explosive-induced real Pyroshock wave propagation can be visualized with high similarity based on the proposed laser technology. (paper)

Optical system for object detection and delineation in space

Science.gov (United States)

Handelman, Amir; Shwartz, Shoam; Donitza, Liad; Chaplanov, Loran

2018-01-01

Object recognition and delineation is an important task in many environments, such as in crime scenes and operating rooms. Marking evidence or surgical tools and attracting the attention of the surrounding staff to the marked objects can affect people's lives. We present an optical system comprising a camera, computer, and small laser projector that can detect and delineate objects in the environment. To prove the optical system's concept, we show that it can operate in a hypothetical crime scene in which a pistol is present and automatically recognize and segment it by various computer-vision algorithms. Based on such segmentation, the laser projector illuminates the actual boundaries of the pistol and thus allows the persons in the scene to comfortably locate and measure the pistol without holding any intermediator device, such as an augmented reality handheld device, glasses, or screens. Using additional optical devices, such as diffraction grating and a cylinder lens, the pistol size can be estimated. The exact location of the pistol in space remains static, even after its removal. Our optical system can be fixed or dynamically moved, making it suitable for various applications that require marking of objects in space.

Transceiver for Space Station Freedom

Science.gov (United States)

Fitzmaurice, M.; Bruno, R.

1990-07-01

This paper describes the design of the Laser Communication Transceiver (LCT) system which was planned to be flight tested as an attached payload on Space Station Freedom. The objective in building and flight-testing the LCT is to perform a broad class of tests addressing the critical aspects of space-based optical communications systems, providing a base of experience for applying laser communications technology toward future communications needs. The LCT's functional and performance requirements and capabilities with respect to acquisition, spatial tracking and pointing, communications, and attitude determination are discussed.

Investigation into the accuracy of a proposed laser diode based multilateration machine tool calibration system

International Nuclear Information System (INIS)

Fletcher, S; Longstaff, A P; Myers, A

2005-01-01

Geometric and thermal calibration of CNC machine tools is required in modern machine shops with volumetric accuracy assessment becoming the standard machine tool qualification in many industries. Laser interferometry is a popular method of measuring the errors but this, and other alternatives, tend to be expensive, time consuming or both. This paper investigates the feasibility of using a laser diode based system that capitalises on the low cost nature of the diode to provide multiple laser sources for fast error measurement using multilateration. Laser diode module technology enables improved wavelength stability and spectral linewidth which are important factors for laser interferometry. With more than three laser sources, the set-up process can be greatly simplified while providing flexibility in the location of the laser sources improving the accuracy of the system

Development of a laser-based heating system for in situ synchrotron-based X-ray tomographic microscopy

Energy Technology Data Exchange (ETDEWEB)

Fife, Julie L., E-mail: julie.fife@psi.ch [Laboratory for Synchrotron Radiation, Swiss Light Source, Paul Scherrer Institut, Villigen (Switzerland); Computational Materials Laboratory, Ecole Polytechnique Federale de Lausanne, Lausanne (Switzerland); Rappaz, Michel [Computational Materials Laboratory, Ecole Polytechnique Federale de Lausanne, Lausanne (Switzerland); Pistone, Mattia [Institute for Geochemistry and Petrology, Swiss Federal Institute of Technology of Zurich, Zurich (Switzerland); Celcer, Tine [Laboratory for Synchrotron Radiation, Swiss Light Source, Paul Scherrer Institut, Villigen (Switzerland); The Centre of Excellence for Biosensors, Instrumentation and Process Control, Solkan (Slovenia); Mikuljan, Gordan [Laboratory for Synchrotron Radiation, Swiss Light Source, Paul Scherrer Institut, Villigen (Switzerland); Stampanoni, Marco [Laboratory for Synchrotron Radiation, Swiss Light Source, Paul Scherrer Institut, Villigen (Switzerland); Institute for Biomedical Engineering, Swiss Federal Institute of Technology and University of Zurich, Zurich (Switzerland)

2012-05-01

A laser-based heating system has been developed at the TOMCAT beamline of the Swiss Light Source for in situ observations of moderate-to-high-temperature applications of materials. Understanding the formation of materials at elevated temperatures is critical for determining their final properties. Synchrotron-based X-ray tomographic microscopy is an ideal technique for studying such processes because high spatial and temporal resolutions are easily achieved and the technique is non-destructive, meaning additional analyses can take place after data collection. To exploit the state-of-the-art capabilities at the tomographic microscopy and coherent radiology experiments (TOMCAT) beamline of the Swiss Light Source, a general-use moderate-to-high-temperature furnace has been developed. Powered by two diode lasers, it provides controlled localized heating, from 673 to 1973 K, to examine many materials systems and their dynamics in real time. The system can also be operated in various thermal modalities. For example, near-isothermal conditions at a given sample location can be achieved with a prescribed time-dependent temperature. This mode is typically used to study isothermal phase transformations; for example, the formation of equiaxed grains in metallic systems or to nucleate and grow bubble foams in silicate melts under conditions that simulate volcanic processes. In another mode, the power of the laser can be fixed and the specimen moved at a constant speed in a user-defined thermal gradient. This is similar to Bridgman solidification, where the thermal gradient and cooling rate control the microstructure formation. This paper details the experimental set-up and provides multiple proofs-of-concept that illustrate the versatility of using this laser-based heating system to explore, in situ, many elevated-temperature phenomena in a variety of materials.

PHARAO space atomic clock: new developments on the laser source

Science.gov (United States)

Saccoccio, Muriel; Loesel, Jacques; Coatantiec, Claude; Simon, Eric; Laurent, Philippe; Lemonde, Pierre; Maksimovic, I.; Abgrall, M.

2017-11-01

The PHARAO project purpose is to open the way for a new atomic clock generation in space, where laser cooling techniques and microgravity allow high frequency stability and accuracy. The French space agency, CNES is funding and managing the clock construction. The French SYRTE and LKB laboratories are scientific and technical advisers for the clock requirements and the follow-up of subsystem development in industrial companies. EADS SODERN is developing two main subsystems of the PHARAO clock: the Laser Source and the Cesium Tube where atoms are cooled, launched, selected and detected by laser beams. The Laser Source includes an optical bench and electronic devices to generate the laser beams required. This paper describes PHARAO and the role laser beams play in its principle of operation. Then we present the Laser Source design, the technologies involved, and the status of development. Lastly, we focus of a key equipment to reach the performances expected, which is the Extended Cavity Laser Diode.

Laser Spot Detection Based on Reaction Diffusion

Directory of Open Access Journals (Sweden)

Alejandro Vázquez-Otero

2016-03-01

Full Text Available Center-location of a laser spot is a problem of interest when the laser is used for processing and performing measurements. Measurement quality depends on correctly determining the location of the laser spot. Hence, improving and proposing algorithms for the correct location of the spots are fundamental issues in laser-based measurements. In this paper we introduce a Reaction Diffusion (RD system as the main computational framework for robustly finding laser spot centers. The method presented is compared with a conventional approach for locating laser spots, and the experimental results indicate that RD-based computation generates reliable and precise solutions. These results confirm the flexibility of the new computational paradigm based on RD systems for addressing problems that can be reduced to a set of geometric operations.

A development of laser-plasma-based soft x-ray microscope system

International Nuclear Information System (INIS)

Nam, Ki Yong; Kim, Kyong Woo; Kim, Kyu Gyeom; Kwon, Young Man; Yoon, Kwon Ha

2003-01-01

Soft x-ray nano-imaging microscopy system for biomedical application with a high resolution about 50 nm has been designed and described, and its integrated techniques also have been studied. The system is mainly composed of soft x-ray generation system, nano-scaled control system, x-ray optical device like a condenser or object mirror, a CCD camera coupled with multichannel plate (MCP) and vacuum system. In the system, soft x-ray is generated from the laser-based plasma by focusing Nd:YAG laser beam on tantalum (Ta) target. In an x-ray optical system, a wolter mirror has been considering condensing the x-ray beam on a biological specimen and zone plate was adapted as an object mirror. A Si 3 N 4 was used as specimen holder for keeping a biological sample alive in atmosphere conditions. A back-illuminated-CCD camera coupled with multichannel plate was determined to set up.

A development of laser-plasma-based soft x-ray microscope system

Energy Technology Data Exchange (ETDEWEB)

Nam, Ki Yong; Kim, Kyong Woo; Kim, Kyu Gyeom; Kwon, Young Man; Yoon, Kwon Ha [X-ray Microscopy Research Center, Wonkwang University, Iksan (Korea, Republic of)

2003-07-01

Soft x-ray nano-imaging microscopy system for biomedical application with a high resolution about 50 nm has been designed and described, and its integrated techniques also have been studied. The system is mainly composed of soft x-ray generation system, nano-scaled control system, x-ray optical device like a condenser or object mirror, a CCD camera coupled with multichannel plate (MCP) and vacuum system. In the system, soft x-ray is generated from the laser-based plasma by focusing Nd:YAG laser beam on tantalum (Ta) target. In an x-ray optical system, a wolter mirror has been considering condensing the x-ray beam on a biological specimen and zone plate was adapted as an object mirror. A Si{sub 3}N{sub 4} was used as specimen holder for keeping a biological sample alive in atmosphere conditions. A back-illuminated-CCD camera coupled with multichannel plate was determined to set up.

Orbital Dynamics of Low-Earth Orbit Laser-Propelled Space Vehicles

International Nuclear Information System (INIS)

Yamakawa, Hiroshi; Funaki, Ikkoh; Komurasaki, Kimiya

2008-01-01

Trajectories applicable to laser-propelled space vehicles with a laser station in low-Earth orbit are investigated. Laser vehicles are initially located in the vicinity of the Earth-orbiting laser station in low-earth orbit at an altitude of several hundreds kilometers, and are accelerated by laser beaming from the laser station. The laser-propelled vehicles start from low-earth orbit and finally escape from the Earth gravity well, enabling interplanetary trajectories and planetary exploration

Improved GPS-based Satellite Relative Navigation Using Femtosecond Laser Relative Distance Measurements

Directory of Open Access Journals (Sweden)

Hyungjik Oh

2016-03-01

Full Text Available This study developed an approach for improving Carrier-phase Differential Global Positioning System (CDGPS based realtime satellite relative navigation by applying laser baseline measurement data. The robustness against the space operational environment was considered, and a Synthetic Wavelength Interferometer (SWI algorithm based on a femtosecond laser measurement model was developed. The phase differences between two laser wavelengths were combined to measure precise distance. Generated laser data were used to improve estimation accuracy for the float ambiguity of CDGPS data. Relative navigation simulations in real-time were performed using the extended Kalman filter algorithm. The GPS and laser-combined relative navigation accuracy was compared with GPS-only relative navigation solutions to determine the impact of laser data on relative navigation. In numerical simulations, the success rate of integer ambiguity resolution increased when laser data was added to GPS data. The relative navigational errors also improved five-fold and two-fold, relative to the GPS-only error, for 250 m and 5 km initial relative distances, respectively. The methodology developed in this study is suitable for application to future satellite formation-flying missions.

Research on correction algorithm of laser positioning system based on four quadrant detector

Science.gov (United States)

Gao, Qingsong; Meng, Xiangyong; Qian, Weixian; Cai, Guixia

2018-02-01

This paper first introduces the basic principle of the four quadrant detector, and a set of laser positioning experiment system is built based on the four quadrant detector. Four quadrant laser positioning system in the actual application, not only exist interference of background light and detector dark current noise, and the influence of random noise, system stability, spot equivalent error can't be ignored, so it is very important to system calibration and correction. This paper analyzes the various factors of system positioning error, and then propose an algorithm for correcting the system error, the results of simulation and experiment show that the modified algorithm can improve the effect of system error on positioning and improve the positioning accuracy.

Laser-based optical detection of explosives

CERN Document Server

Pellegrino, Paul M; Farrell, Mikella E

2015-01-01

Laser-Based Optical Detection of Explosives offers a comprehensive review of past, present, and emerging laser-based methods for the detection of a variety of explosives. This book: Considers laser propagation safety and explains standard test material preparation for standoff optical-based detection system evaluation Explores explosives detection using deep ultraviolet native fluorescence, Raman spectroscopy, laser-induced breakdown spectroscopy, reflectometry, and hyperspectral imaging Examines photodissociation followed by laser-induced fluorescence, photothermal methods, cavity-enhanced absorption spectrometry, and short-pulse laser-based techniques Describes the detection and recognition of explosives using terahertz-frequency spectroscopic techniques Each chapter is authored by a leading expert on the respective technology, and is structured to supply historical perspective, address current advantages and challenges, and discuss novel research and applications. Readers are left with an in-depth understa...

Fundamentals of metasurface lasers based on resonant dark states

International Nuclear Information System (INIS)

Droulias, Sotiris; Technology - Hellas; Jain, Aditya; Koschny, Thomas; Soukoulis, Costas M.; Technology - Hellas; Ames Laboratory and Iowa State University, Ames, IA

2017-01-01

Recently, our group proposed a metamaterial laser design based on explicitly coupled dark resonant states in low-loss dielectrics, which conceptually separates the gain-coupled resonant photonic state responsible for macroscopic stimulated emission from the coupling to specific free-space propagating modes, allowing independent adjustment of the lasing state and its coherent radiation output. Due to this functionality, it is now possible to make lasers that can overcome the trade-off between system dimensions and Q factor, especially for surface emitting lasers with deeply subwavelength thickness. In this paper, we give a detailed discussion of the key functionality and benefits of this design, such as radiation damping tunability, directionality, subwavelength integration, and simple layer-by-layer fabrication. Finally, we examine in detail the fundamental design tradeoffs that establish the principle of operation and must be taken into account and give guidance for realistic implementations.

Direct longitudinal laser acceleration of electrons in free space

Directory of Open Access Journals (Sweden)

Sergio Carbajo

2016-02-01

Full Text Available Compact laser-driven accelerators are pursued heavily worldwide because they make novel methods and tools invented at national laboratories widely accessible in science, health, security, and technology [V. Malka et al., Principles and applications of compact laser-plasma accelerators, Nat. Phys. 4, 447 (2008]. Current leading laser-based accelerator technologies [S. P. D. Mangles et al., Monoenergetic beams of relativistic electrons from intense laser-plasma interactions, Nature (London 431, 535 (2004; T. Toncian et al., Ultrafast laser-driven microlens to focus and energy-select mega-electron volt protons, Science 312, 410 (2006; S. Tokita et al. Single-shot ultrafast electron diffraction with a laser-accelerated sub-MeV electron pulse, Appl. Phys. Lett. 95, 111911 (2009] rely on a medium to assist the light to particle energy transfer. The medium imposes material limitations or may introduce inhomogeneous fields [J. R. Dwyer et al., Femtosecond electron diffraction: “Making the molecular movie,”, Phil. Trans. R. Soc. A 364, 741 (2006]. The advent of few cycle ultraintense radially polarized lasers [S. Carbajo et al., Efficient generation of ultraintense few-cycle radially polarized laser pulses, Opt. Lett. 39, 2487 (2014] has ushered in a novel accelerator concept [L. J. Wong and F. X. Kärtner, Direct acceleration of an electron in infinite vacuum by a pulsed radially polarized laser beam, Opt. Express 18, 25035 (2010; F. Pierre-Louis et al. Direct-field electron acceleration with ultrafast radially polarized laser beams: Scaling laws and optimization, J. Phys. B 43, 025401 (2010; Y. I. Salamin, Electron acceleration from rest in vacuum by an axicon Gaussian laser beam, Phys. Rev. A 73, 043402 (2006; C. Varin and M. Piché, Relativistic attosecond electron pulses from a free-space laser-acceleration scheme, Phys. Rev. E 74, 045602 (2006; A. Sell and F. X. Kärtner, Attosecond electron bunches accelerated and

Neural network approximation of nonlinearity in laser nano-metrology system based on TLMI

Energy Technology Data Exchange (ETDEWEB)

Olyaee, Saeed; Hamedi, Samaneh, E-mail: s_olyaee@srttu.edu [Nano-photonics and Optoelectronics Research Laboratory (NORLab), Faculty of Electrical and Computer Engineering, Shahid Rajaee Teacher Training University (SRTTU), Lavizan, 16788, Tehran (Iran, Islamic Republic of)

2011-02-01

In this paper, an approach based on neural network (NN) for nonlinearity modeling in a nano-metrology system using three-longitudinal-mode laser heterodyne interferometer (TLMI) for length and displacement measurements is presented. We model nonlinearity errors that arise from elliptically and non-orthogonally polarized laser beams, rotational error in the alignment of laser head with respect to the polarizing beam splitter, rotational error in the alignment of the mixing polarizer, and unequal transmission coefficients in the polarizing beam splitter. Here we use a neural network algorithm based on the multi-layer perceptron (MLP) network. The simulation results show that multi-layer feed forward perceptron network is successfully applicable to real noisy interferometer signals.

Neural network approximation of nonlinearity in laser nano-metrology system based on TLMI

International Nuclear Information System (INIS)

Olyaee, Saeed; Hamedi, Samaneh

2011-01-01

In this paper, an approach based on neural network (NN) for nonlinearity modeling in a nano-metrology system using three-longitudinal-mode laser heterodyne interferometer (TLMI) for length and displacement measurements is presented. We model nonlinearity errors that arise from elliptically and non-orthogonally polarized laser beams, rotational error in the alignment of laser head with respect to the polarizing beam splitter, rotational error in the alignment of the mixing polarizer, and unequal transmission coefficients in the polarizing beam splitter. Here we use a neural network algorithm based on the multi-layer perceptron (MLP) network. The simulation results show that multi-layer feed forward perceptron network is successfully applicable to real noisy interferometer signals.

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.

Development of Operational Free-Space-Optical (FSO) Laser Communication Systems Final Report CRADA No. TC02093.0

Energy Technology Data Exchange (ETDEWEB)

Ruggiero, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Orgren, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-08-15

This project was a collaborative effort between Lawrence Livermore National Security, LLC (formerly The Regents of the University of California)/Lawrence Livermore National Laboratory (LLNL) and LGS Innovations, LLC (formerly Lucent Technologies, Inc.), to develop long-range and mobile operational free-space optical (FSO) laser communication systems for specialized government applications. LLNL and LGS Innovations formerly Lucent Bell Laboratories Government Communications Systems performed this work for a United States Government (USG) Intelligence Work for Others (I-WFO) customer, also referred to as "Government Customer", or "Customer" and "Government Sponsor." The CRADA was a critical and required part of the LLNL technology transfer plan for the customer.

Polarization measurements through space-to-ground atmospheric propagation paths by using a highly polarized laser source in space.

Science.gov (United States)

Toyoshima, Morio; Takenaka, Hideki; Shoji, Yozo; Takayama, Yoshihisa; Koyama, Yoshisada; Kunimori, Hiroo

2009-12-07

The polarization characteristics of an artificial laser source in space were measured through space-to-ground atmospheric transmission paths. An existing Japanese laser communication satellite and optical ground station were used to measure Stokes parameters and the degree of polarization of the laser beam transmitted from the satellite. As a result, the polarization was preserved within an rms error of 1.6 degrees, and the degree of polarization was 99.4+/-4.4% through the space-to-ground atmosphere. These results contribute to the link estimation for quantum key distribution via space and provide the potential for enhancements in quantum cryptography worldwide in the future.

Laser application for nuclear reaction product detecting system alignment

International Nuclear Information System (INIS)

Grantsev, V.I.; Dryapachenko, I.P.; Kornilov, V.A.; Nemets, O.F.; Rudenko, B.A.; Sokolov, M.V.; Struzhko, B.G.; Gnatovskij, A.V.; Bojchuk, V.N.

1982-01-01

A method for optical alignment of nuclear particle detector system using a laser beam and hologram is described. The method permits to arrange detectors very precisely in accordance with any chosen space coordinate values. The results of modelling the geometry of an experiment based on using the suggested method on cyclotron beams are described. A gas helium-neon laser with wavelength of 0.63 μm radiation power of an order of 2 MW and angular beam divergence less than 10 angular minutes is used for modelling. It is concluded that the laser and hologram application provides large possibilities for the modelling the geometry of experiments on nuclear reaction investigation. When necessary it is possible to obtain small nonius scale of reference beams by means of multiplicating properties of the wave front modulator-hologram system. It is also possible to record holograms shaping the reference beams in two or several planes crossing along the central beam direction. Such holograms can be used for modelling the noncoplanar geometry of correlation experiments [ru

Solar Pumped High Power Solid State Laser for Space Applications

Science.gov (United States)

Fork, Richard L.; Laycock, Rustin L.; Green, Jason J. A.; Walker, Wesley W.; Cole, Spencer T.; Frederick, Kevin B.; Phillips, Dane J.

2004-01-01

Highly coherent laser light provides a nearly optimal means of transmitting power in space. The simplest most direct means of converting sunlight to coherent laser light is a solar pumped laser oscillator. A key need for broadly useful space solar power is a robust solid state laser oscillator capable of operating efficiently in near Earth space at output powers in the multi hundred kilowatt range. The principal challenges in realizing such solar pumped laser oscillators are: (1) the need to remove heat from the solid state laser material without introducing unacceptable thermal shock, thermal lensing, or thermal stress induced birefringence to a degree that improves on current removal rates by several orders of magnitude and (2) to introduce sunlight at an effective concentration (kW/sq cm of laser cross sectional area) that is several orders of magnitude higher than currently available while tolerating a pointing error of the spacecraft of several degrees. We discuss strategies for addressing these challenges. The need to remove the high densities of heat, e.g., 30 kW/cu cm, while keeping the thermal shock, thermal lensing and thermal stress induced birefringence loss sufficiently low is addressed in terms of a novel use of diamond integrated with the laser material, such as Ti:sapphire in a manner such that the waste heat is removed from the laser medium in an axial direction and in the diamond in a radial direction. We discuss means for concentrating sunlight to an effective areal density of the order of 30 kW/sq cm. The method integrates conventional imaging optics, non-imaging optics and nonlinear optics. In effect we use a method that combines some of the methods of optical pumping solid state materials and optical fiber, but also address laser media having areas sufficiently large, e.g., 1 cm diameter to handle the multi-hundred kilowatt level powers needed for space solar power.

Solar-pumped solid state Nd lasers

Science.gov (United States)

Williams, M. D.; Zapata, L.

1985-01-01

Solid state neodymium lasers are considered candidates for space-based polar-pumped laser for continuous power transmission. Laser performance for three different slab laser configurations has been computed to show the excellent power capability of such systems if heat problems can be solved. Ideas involving geometries and materials are offered as potential solutions to the heat problem.

Applying Model Based Systems Engineering to NASA's Space Communications Networks

Science.gov (United States)

Bhasin, Kul; Barnes, Patrick; Reinert, Jessica; Golden, Bert

2013-01-01

System engineering practices for complex systems and networks now require that requirement, architecture, and concept of operations product development teams, simultaneously harmonize their activities to provide timely, useful and cost-effective products. When dealing with complex systems of systems, traditional systems engineering methodology quickly falls short of achieving project objectives. This approach is encumbered by the use of a number of disparate hardware and software tools, spreadsheets and documents to grasp the concept of the network design and operation. In case of NASA's space communication networks, since the networks are geographically distributed, and so are its subject matter experts, the team is challenged to create a common language and tools to produce its products. Using Model Based Systems Engineering methods and tools allows for a unified representation of the system in a model that enables a highly related level of detail. To date, Program System Engineering (PSE) team has been able to model each network from their top-level operational activities and system functions down to the atomic level through relational modeling decomposition. These models allow for a better understanding of the relationships between NASA's stakeholders, internal organizations, and impacts to all related entities due to integration and sustainment of existing systems. Understanding the existing systems is essential to accurate and detailed study of integration options being considered. In this paper, we identify the challenges the PSE team faced in its quest to unify complex legacy space communications networks and their operational processes. We describe the initial approaches undertaken and the evolution toward model based system engineering applied to produce Space Communication and Navigation (SCaN) PSE products. We will demonstrate the practice of Model Based System Engineering applied to integrating space communication networks and the summary of its

Synchronized femtosecond laser pulse switching system based nano-patterning technology

Science.gov (United States)

Sohn, Ik-Bu; Choi, Hun-Kook; Yoo, Dongyoon; Noh, Young-Chul; Sung, Jae-Hee; Lee, Seong-Ku; Ahsan, Md. Shamim; Lee, Ho

2017-07-01

This paper demonstrates the design and development of a synchronized femtosecond laser pulse switching system and its applications in nano-patterning of transparent materials. Due to synchronization, we are able to control the location of each irradiated laser pulse in any kind of substrate. The control over the scanning speed and scanning step of the laser beam enables us to pattern periodic micro/nano-metric holes, voids, and/or lines in various materials. Using the synchronized laser system, we pattern synchronized nano-holes on the surface of and inside various transparent materials including fused silica glass and polymethyl methacrylate to replicate any image or pattern on the surface of or inside (transparent) materials. We also investigate the application areas of the proposed synchronized femtosecond laser pulse switching system in a diverse field of science and technology, especially in optical memory, color marking, and synchronized micro/nano-scale patterning of materials.

Johnson Space Center's Solar and Wind-Based Renewable Energy System

Science.gov (United States)

Vasquez, A.; Ewert, M.; Rowlands, J.; Post, K.

2009-01-01

The NASA Johnson Space Center (JSC) in Houston, Texas has a Sustainability Partnership team that seeks ways for earth-based sustainability practices to also benefit space exploration research. A renewable energy gathering system was installed in 2007 at the JSC Child Care Center (CCC) which also offers a potential test bed for space exploration power generation and remote monitoring and control concepts. The system comprises: 1) several different types of photovoltaic panels (29 kW), 2) two wind-turbines (3.6 kW total), and 3) one roof-mounted solar thermal water heater and tank. A tie to the JSC local electrical grid was provided to accommodate excess power. The total first year electrical energy production was 53 megawatt-hours. A web-based real-time metering system collects and reports system performance and weather data. Improvements in areas of the CCC that were detected during subsequent energy analyses and some concepts for future efforts are also presented.

Laser engineering of microbial systems

Science.gov (United States)

Yusupov, V. I.; Gorlenko, M. V.; Cheptsov, V. S.; Minaev, N. V.; Churbanova, E. S.; Zhigarkov, V. S.; Chutko, E. A.; Evlashin, S. A.; Chichkov, B. N.; Bagratashvili, V. N.

2018-06-01

A technology of laser engineering of microbial systems (LEMS) based on the method of laser-induced transfer of heterogeneous mixtures containing microorganisms (laser bioprinting) is described. This technology involves laser printing of soil microparticles by focusing near-infrared laser pulses on a specially prepared gel/soil mixture spread onto a gold-coated glass plate. The optimal range of laser energies from the point of view of the formation of stable jets and droplets with minimal negative impact on living systems of giant accelerations, laser pulse irradiation, and Au nanoparticles was found. Microsamples of soil were printed on glucose-peptone-yeast agar plates to estimate the LEMS process influence on structural and morphological microbial diversity. The obtained results were compared with traditionally treated soil samples. It was shown that LEMS technology allows significantly increasing the biodiversity of printed organisms and is effective for isolating rare or unculturable microorganisms.

Space nuclear reactor system diagnosis: Knowledge-based approach

International Nuclear Information System (INIS)

Ting, Y.T.D.

1990-01-01

SP-100 space nuclear reactor system development is a joint effort by the Department of Energy, the Department of Defense and the National Aeronautics and Space Administration. The system is designed to operate in isolation for many years, and is possibly subject to little or no remote maintenance. This dissertation proposes a knowledge based diagnostic system which, in principle, can diagnose the faults which can either cause reactor shutdown or lead to another serious problem. This framework in general can be applied to the fully specified system if detailed design information becomes available. The set of faults considered herein is identified based on heuristic knowledge about the system operation. The suitable approach to diagnostic problem solving is proposed after investigating the most prevalent methodologies in Artificial Intelligence as well as the causal analysis of the system. Deep causal knowledge modeling based on digraph, fault-tree or logic flowgraph methodology would present a need for some knowledge representation to handle the time dependent system behavior. A proposed qualitative temporal knowledge modeling methodology, using rules with specified time delay among the process variables, has been proposed and is used to develop the diagnostic sufficient rule set. The rule set has been modified by using a time zone approach to have a robust system design. The sufficient rule set is transformed to a sufficient and necessary one by searching the whole knowledge base. Qualitative data analysis is proposed in analyzing the measured data if in a real time situation. An expert system shell - Intelligence Compiler is used to develop the prototype system. Frames are used for the process variables. Forward chaining rules are used in monitoring and backward chaining rules are used in diagnosis

An Experimental Study on Energy Conversion Process of an in-Space CW Laser Thruster

International Nuclear Information System (INIS)

Uehara, Susumu; Inoue, Takayoshi; Komurasaki, Kimiya; Arakawa, Yoshihiro

2005-01-01

CW laser propulsion has been investigated to develop a prospective propulsion system that may be used in space. OTV (Orbit Transfer Vehicle) is placed as one of the most effective applications of the propulsion system. In this study, the energy partitioning of incident laser energy was investigated over the wide range of velocity of the flow field in low pressure. Flow velocity is thought to have significant effects on energy conversion process because the distribution of temperature and the position of a laser sustained plasma in the focusing laser beam should be determined so that flow velocity and propagation velocity of optical discharge balance out. It was found that the higher energy conversion efficiency can be achieved by lowering the pressure and increasing the velocity of the flow field

Parametric study of laser photovoltaic energy converters

Science.gov (United States)

Walker, G. H.; Heinbockel, J. H.

1987-01-01

Photovoltaic converters are of interest for converting laser power to electrical power in a space-based laser power system. This paper describes a model for photovoltaic laser converters and the application of this model to a neodymium laser silicon photovoltaic converter system. A parametric study which defines the sensitivity of the photovoltaic parameters is described. An optimized silicon photovoltaic converter has an efficiency greater than 50 percent for 1000 W/sq cm of neodymium laser radiation.

Space Based Infrared System High (SBIRS High)

Science.gov (United States)

2015-12-01

elements (five SMGTs) for the S2E2 Mobile Ground System. ​ SBIRS Block Buy (GEO 5-6) The GEO 5-6 Tech Refresh (TR) Engineering Change Proposal was...Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-210 Space Based Infrared System High ( SBIRS High) As of FY 2017 President’s Budget Defense...Acquisition Management Information Retrieval (DAMIR) March 23, 2016 11:24:26 UNCLASSIFIED SBIRS High December 2015 SAR March 23, 2016 11:24:26

A Space Based Solar Power Satellite System

Science.gov (United States)

Engel, J. M.; Polling, D.; Ustamujic, F.; Yaldiz, R.; et al.

2002-01-01

(SPoTS) supplying other satellites with energy. SPoTS is due to be commercially viable and operative in 2020. of Technology designed the SPoTS during a full-time design period of six weeks as a third year final project. The team, organized according to the principles of systems engineering, first conducted a literature study on space wireless energy transfer to select the most suitable candidates for use on the SPoTS. After that, several different system concepts have been generated and evaluated, the most promising concept being worked out in greater detail. km altitude. Each SPoTS satellite has a 50m diameter inflatable solar collector that focuses all received sunlight. Then, the received sunlight is further redirected by means of four pointing mirrors toward four individual customer satellites. A market-analysis study showed, that providing power to geo-stationary communication satellites during their eclipse would be most beneficial. At arrival at geo-stationary orbit, the focused beam has expended to such an extent that its density equals one solar flux. This means that customer satellites can continue to use their regular solar arrays during their eclipse for power generation, resulting in a satellite battery mass reduction. the customer satellites in geo-stationary orbit, the transmitted energy beams needs to be pointed with very high accuracy. Computations showed that for this degree of accuracy, sensors are needed, which are not mainstream nowadays. Therefore further research must be conducted in this area in order to make these high-accuracy-pointing systems commercially attractive for use on the SPoTS satellites around 2020. Total 20-year system lifetime cost for 18 SPoT satellites are estimated at approximately USD 6 billion [FY2001]. In order to compete with traditional battery-based satellite power systems or possible ground based wireless power transfer systems the price per kWh for the customer must be significantly lower than the present one

A compact frequency stabilized telecom laser diode for space applications

Science.gov (United States)

Philippe, C.; Holleville, D.; Le Targat, R.; Wolf, P.; Leveque, T.; Le Goff, R.; Martaud, E.; Acef, O.

2017-09-01

We report on a Telecom laser diode (LD) frequency stabilization to a narrow iodine hyperfine line in the green range, after frequency tripling process using fibered nonlinear waveguide PPLN crystals. We have generated up to 300 mW optical power in the green range ( 514 nm) from 800 mW of infrared power ( 1542 nm), corresponding to a nonlinear conversion efficiency h = P3?/P? 36%. Less than 10 mW of the generated green power are used for Doppler-free spectroscopy of 127I2 molecular iodine, and -therefore- for the frequency stabilization purpose. The frequency tripling optical setup is very compact (test the potential of this new frequency standard based on the couple "1.5 ?m laser / iodine molecule". We have already demonstrated a preliminary frequency stability of 4.8 x 10-14 ? -1/2 with a minimum value of 6 x 10-15 reached after 50 s of integration time, conferred to a laser diode operating at 1542.1 nm. We focus now our efforts to expand the frequency stability to a longer integration time in order to meet requirements of many space experiments, such earth gravity missions, inters satellites links or space to ground communications. Furthermore, we investigate the potential of a new approach based on frequency modulation technique (FM), associated to a 3rd harmonic detection of iodine lines to increase the compactness of the optical setup.

Analysis of CPolSK-based FSO system working in space-to-ground channel

Science.gov (United States)

Su, Yuwei; Sato, Takuro

2018-03-01

In this article, the transmission performance of a circle polarization shift keying (CPolSK)-based free space optical (FSO) system working in space-to-ground channel is analyzed. Formulas describing the optical polarization distortion caused by the atmospheric turbulence and the communication qualities in terms of signal-to-noise-ratio (SNR), bit-error-ratio (BER) and outage probability of the proposed system are derived. Based on the Stokes parameters data measured by a Japanese optical communication satellite, we evaluate the space-to-ground FSO link and simulate the system performance under a varying regime of turbulence strength. The proposed system provides a more efficient way to compensate scintillation effects in a comparison with the on-off-keying (OOK)-based FSO system. These results are useful to the designing and evaluating of a deep space FSO communication system.

Coherent laser vision system

International Nuclear Information System (INIS)

Sebastion, R.L.

1995-01-01

The Coherent Laser Vision System (CLVS) is being developed to provide precision real-time 3D world views to support site characterization and robotic operations and during facilities Decontamination and Decommissioning. Autonomous or semiautonomous robotic operations requires an accurate, up-to-date 3D world view. Existing technologies for real-time 3D imaging, such as AM laser radar, have limited accuracy at significant ranges and have variability in range estimates caused by lighting or surface shading. Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no-moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic to coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system

Coherent laser vision system

Energy Technology Data Exchange (ETDEWEB)

Sebastion, R.L. [Coleman Research Corp., Springfield, VA (United States)

1995-10-01

The Coherent Laser Vision System (CLVS) is being developed to provide precision real-time 3D world views to support site characterization and robotic operations and during facilities Decontamination and Decommissioning. Autonomous or semiautonomous robotic operations requires an accurate, up-to-date 3D world view. Existing technologies for real-time 3D imaging, such as AM laser radar, have limited accuracy at significant ranges and have variability in range estimates caused by lighting or surface shading. Recent advances in fiber optic component technology and digital processing components have enabled the development of a new 3D vision system based upon a fiber optic FMCW coherent laser radar. The approach includes a compact scanner with no-moving parts capable of randomly addressing all pixels. The system maintains the immunity to lighting and surface shading conditions which is characteristic to coherent laser radar. The random pixel addressability allows concentration of scanning and processing on the active areas of a scene, as is done by the human eye-brain system.

Novel diode-based laser system for combined transcutaneous monitoring and computer-controlled intermittent treatment of jaundiced neonates

Science.gov (United States)

Hamza, Mostafa; El-Ahl, Mohammad H. S.; Hamza, Ahmad M.

2001-06-01

The high efficacy of laser phototherapy combined with transcutaneous monitoring of serum bilirubin provides optimum safety for jaundiced infants from the risk of bilirubin encephalopathy. In this paper the authors introduce the design and operating principles of a new laser system that can provide simultaneous monitoring and treatment of several jaundiced babies at one time. The new system incorporates diode-based laser sources oscillating at selected wavelengths to achieve both transcutaneous differential absorption measurements of bilirubin concentration in addition to the computer controlled intermittent laser therapy through a network of optical fibers. The detailed description and operating characteristics of this system are presented.

Characterizing Accreting Double White Dwarf Binaries with the Laser Interferometer Space Antenna and Gaia

Science.gov (United States)

Breivik, Katelyn; Kremer, Kyle; Bueno, Michael; Larson, Shane L.; Coughlin, Scott; Kalogera, Vassiliki

2018-02-01

We demonstrate a method to fully characterize mass-transferring double white dwarf (DWD) systems with a helium-rich (He) white dwarf (WD) donor based on the mass–radius (M–R) relationship for He WDs. Using a simulated Galactic population of DWDs, we show that donor and accretor masses can be inferred for up to ∼60 systems observed by both Laser Interferometer Space Antenna (LISA) and Gaia. Half of these systems will have mass constraints {{Δ }} {M}{{D}} ≲ 0.2 {M}ȯ and {{Δ }} {M}{{A}} ≲ 2.3 {M}ȯ . We also show how the orbital frequency evolution due to astrophysical processes and gravitational radiation can be decoupled from the total orbital frequency evolution for up to ∼50 of these systems.

Laser Spot Tracking Based on Modified Circular Hough Transform and Motion Pattern Analysis

Science.gov (United States)

Krstinić, Damir; Skelin, Ana Kuzmanić; Milatić, Ivan

2014-01-01

Laser pointers are one of the most widely used interactive and pointing devices in different human-computer interaction systems. Existing approaches to vision-based laser spot tracking are designed for controlled indoor environments with the main assumption that the laser spot is very bright, if not the brightest, spot in images. In this work, we are interested in developing a method for an outdoor, open-space environment, which could be implemented on embedded devices with limited computational resources. Under these circumstances, none of the assumptions of existing methods for laser spot tracking can be applied, yet a novel and fast method with robust performance is required. Throughout the paper, we will propose and evaluate an efficient method based on modified circular Hough transform and Lucas–Kanade motion analysis. Encouraging results on a representative dataset demonstrate the potential of our method in an uncontrolled outdoor environment, while achieving maximal accuracy indoors. Our dataset and ground truth data are made publicly available for further development. PMID:25350502

Laser spot tracking based on modified circular Hough transform and motion pattern analysis.

Science.gov (United States)

Krstinić, Damir; Skelin, Ana Kuzmanić; Milatić, Ivan

2014-10-27

Laser pointers are one of the most widely used interactive and pointing devices in different human-computer interaction systems. Existing approaches to vision-based laser spot tracking are designed for controlled indoor environments with the main assumption that the laser spot is very bright, if not the brightest, spot in images. In this work, we are interested in developing a method for an outdoor, open-space environment, which could be implemented on embedded devices with limited computational resources. Under these circumstances, none of the assumptions of existing methods for laser spot tracking can be applied, yet a novel and fast method with robust performance is required. Throughout the paper, we will propose and evaluate an efficient method based on modified circular Hough transform and Lucas-Kanade motion analysis. Encouraging results on a representative dataset demonstrate the potential of our method in an uncontrolled outdoor environment, while achieving maximal accuracy indoors. Our dataset and ground truth data are made publicly available for further development.

Nova laser alignment control system

International Nuclear Information System (INIS)

Van Arsdall, P.J.; Holloway, F.W.; McGuigan, D.L.; Shelton, R.T.

1984-01-01

Alignment of the Nova laser requires control of hundreds of optical components in the ten beam paths. Extensive application of computer technology makes daily alignment practical. The control system is designed in a manner which provides both centralized and local manual operator controls integrated with automatic closed loop alignment. Menudriven operator consoles using high resolution color graphics displays overlaid with transport touch panels allow laser personnel to interact efficiently with the computer system. Automatic alignment is accomplished by using image analysis techniques to determine beam references points from video images acquired along the laser chain. A major goal of the design is to contribute substantially to rapid experimental turnaround and consistent alignment results. This paper describes the computer-based control structure and the software methods developed for aligning this large laser system

Laser-Supported Detonation Concept as a Space Thruster

International Nuclear Information System (INIS)

Fujiwara, Toshi; Miyasaka, Takeshi

2004-01-01

Similar to the concept of pulse detonation engine (PDE), a detonation generated in the 'combustion chamber' due to incoming laser absorption can produce the thrust basically much higher than the one that a laser-supported deflagration wave can provide. Such a laser-supported detonation wave concept has been theoretically studied by the first author for about 20 years in view of its application to space propulsion. The entire work is reviewed in the present paper. The initial condition for laser absorption can be provided by increasing the electron density using electric discharge. Thereafter, once a standing/running detonation wave is formed, the laser absorption can continuously be performed by the classical absorption mechanism called Inverse Bremsstrahlung behind a strong shock wave

Compact laser-diode-based femtosecond sources

International Nuclear Information System (INIS)

Brown, C T A; Cataluna, M A; Lagatsky, A A; Rafailov, E U; Agate, M B; Leburn, C G; Sibbett, W

2004-01-01

This paper describes the development of compact femtosecond laser systems that are capable of being directly pumped by laser diodes or are based directly on laser diodes. The paper demonstrates the latest results in a highly efficient vibronic based gain medium and a diode-pumped Yb:KYW laser is reported that has a wall plug efficiency >14%. A Cr 4+ :YAG oscillator is described that generates transform-limited pulses of 81 fs duration at a pulse repetition frequency of >4 GHz. The development of Cr 3+ :LiSAF lasers that can be operated using power supplies based on batteries is briefly discussed. We also present a summary of work being carried out on the generation of fs-pulses from laser diodes and discuss the important issues in this area. Finally, we outline results obtained on the generation of pulses as short as 550 fs directly from a two-section quantum dot laser without any external pulse compression

Portable detection system of vegetable oils based on laser induced fluorescence

Science.gov (United States)

Zhu, Li; Zhang, Yinchao; Chen, Siying; Chen, He; Guo, Pan; Mu, Taotao

2015-11-01

Food safety, especially edible oils, has attracted more and more attention recently. Many methods and instruments have emerged to detect the edible oils, which include oils classification and adulteration. It is well known than the adulteration is based on classification. Then, in this paper, a portable detection system, based on laser induced fluorescence, is proposed and designed to classify the various edible oils, including (olive, rapeseed, walnut, peanut, linseed, sunflower, corn oils). 532 nm laser modules are used in this equipment. Then, all the components are assembled into a module (100*100*25mm). A total of 700 sets of fluorescence data (100 sets of each type oil) are collected. In order to classify different edible oils, principle components analysis and support vector machine have been employed in the data analysis. The training set consisted of 560 sets of data (80 sets of each oil) and the test set consisted of 140 sets of data (20 sets of each oil). The recognition rate is up to 99%, which demonstrates the reliability of this potable system. With nonintrusive and no sample preparation characteristic, the potable system can be effectively applied for food detection.

Laser-based gas sensors keep moisture out of pipelines

Energy Technology Data Exchange (ETDEWEB)

Anon.

2006-07-15

Natural gas often contains contaminants that cause corrosion, and long-term deterioration, and must be cleaned and brought to pipeline standards before it can be delivered to high-pressure, long-distance pipelines. Many older sensors produce false data that can result in contaminated gas getting through. This article presented details of the SpectraSensor, a new laser-based sensor technology used by the El Paso Natural Gas Company (EPNG). The SpectraSensor is comprised of a tunable diode laser (TDL) based technology developed by the National American Space Agency (NASA). The gas analyzer provides non-contact measurement of moisture, carbon dioxide, and other corrosives in natural gas pipelines, and the tunable laser-based gas sensors are fast, accurate, and flexible. Producers can monitor El Paso's gas analyzer readings by capturing the electronic signal from El Paso's unit via a SCADA system and view the readings from control rooms. While initial purchase price is higher than more problematic surface-based gas sensors, an evaluation of the technology has indicated that maintenance savings alone may provide an almost immediate return on investments. Unlike electrochemical and crystal gas sensors, laser-based gas analyzers do not come into direct contact with any substances, a fact which practically eliminates maintenance and operational costs. Studies have shown that the cost of operating conventional electrochemical sensors can result in a cumulative annual expense exceeding $50,000 per unit including labour; recalibration and rebuilding; back-up sensor heads; and gas dehydration and tariffs. 1 fig.

Advanced technologies in the ASI MLRO towards a new generation laser ranging system

Science.gov (United States)

Varghese, Thomas; Bianco, Giuseppe

1994-01-01

Matera Laser Ranging Observatory (MLRO) is a high performance, highly automated optical and astronomical observatory currently under design and development by AlliedSignal for the Italian Space Agency (ASI). It is projected to become operational at the Centro Geodesia Spaziale in Matera, Italy, in 1997. MLRO, based on a 1.5-meter astronomical quality telescope, will perform ranging to spacecraft in earthbound orbits, lunar reflectors, and specially equipped deep space missions. The primary emphasis during design is to incorporate state-of-the-art technologies to produce an intelligent, automated, high accuracy ranging system that will mimic the characteristic features of a fifth generation laser ranging system. The telescope has multiple ports and foci to support future experiments in the areas of laser communications, lidar, astrometry, etc. The key features providing state-of-the-art ranging performance include: a diode-pumped picosecond (50 ps) laser, high speed (3-5 GHz) optoelectronic detection and signal processing, and a high accuracy (6 ps) high resolution (less than 2 ps) time measurement capability. The above combination of technologies is expected to yield millimeter laser ranging precision and accuracy on targets up to 300,000 km, surpassing the best operational instrument performance to date by a factor of five or more. Distributed processing and control using a state-of-the-art computing environment provides the framework for efficient operation, system optimization, and diagnostics. A computationally intelligent environment permits optimal planning, scheduling, tracking, and data processing. It also supports remote access, monitor, and control for joint experiments with other observatories.

Compact mode-locked diode laser system for high precision frequency comparisons in microgravity

Science.gov (United States)

Christopher, H.; Kovalchuk, E. V.; Wicht, A.; Erbert, G.; Tränkle, G.; Peters, A.

2017-11-01

Nowadays cold atom-based quantum sensors such as atom interferometers start leaving optical labs to put e.g. fundamental physics under test in space. One of such intriguing applications is the test of the Weak Equivalence Principle, the Universality of Free Fall (UFF), using different quantum objects such as rubidium (Rb) and potassium (K) ultra-cold quantum gases. The corresponding atom interferometers are implemented with light pulses from narrow linewidth lasers emitting near 767 nm (K) and 780 nm (Rb). To determine any relative acceleration of the K and Rb quantum ensembles during free fall, the frequency difference between the K and Rb lasers has to be measured very accurately by means of an optical frequency comb. Micro-gravity applications not only require good electro-optical characteristics but are also stringent in their demand for compactness, robustness and efficiency. For frequency comparison experiments the rather complex fiber laser-based frequency comb system may be replaced by one semiconductor laser chip and some passive components. Here we present an important step towards this direction, i.e. we report on the development of a compact mode-locked diode laser system designed to generate a highly stable frequency comb in the wavelength range of 780 nm.

A distributed data base management system. [for Deep Space Network

Science.gov (United States)

Bryan, A. I.

1975-01-01

Major system design features of a distributed data management system for the NASA Deep Space Network (DSN) designed for continuous two-way deep space communications are described. The reasons for which the distributed data base utilizing third-generation minicomputers is selected as the optimum approach for the DSN are threefold: (1) with a distributed master data base, valid data is available in real-time to support DSN management activities at each location; (2) data base integrity is the responsibility of local management; and (3) the data acquisition/distribution and processing power of a third-generation computer enables the computer to function successfully as a data handler or as an on-line process controller. The concept of the distributed data base is discussed along with the software, data base integrity, and hardware used. The data analysis/update constraint is examined.

Femtosecond laser-induced concentric ring microstructures on Zr-based metallic glass

International Nuclear Information System (INIS)

Ma Fengxu; Yang Jianjun; Xiaonong Zhu; Liang Chunyong; Wang Hongshui

2010-01-01

Surface morphological evolution of Zr-based metallic glass ablated by femtosecond lasers is investigated in atmosphere condition. Three types of permanent ring structures with micro-level spacing are observed for different laser shots and fluences. In the case of low laser fluences, the generation of annular patterns with nonthermal features is observed on the rippled structure with the subwavelength scale, and the ring spacing shows a decrease tendency from the center to the margin. While in the case of high laser fluences, the concentric rings formation within the laser spot is found to have evident molten traces and display the increasing ring spacing along the radial direction. Moreover, when the laser shots accumulation becomes large, the above two types of ring microstructures begin to develop into the common ablation craters. Analysis and discussion suggests that the stress-induced condensation of ablation vapors and the frozen thermocapillary waves on the molten surfaces should be responsible for the formation of two different types of concentric ring structures, respectively. Eventually, a processing window for each resulting surface microstructure type is obtained experimentally and indicates the possibility to control the morphological transitions among different types.

Goddard Technology Efforts to Improve Space Borne Laser Reliability

Science.gov (United States)

Heaps, William S.

2006-01-01

In an effort to reduce the risk, perceived and actual, of employing instruments containing space borne lasers NASA initiated the Laser Risk Reduction Program (LRRP) in 2001. This program managed jointly by NASA Langley and NASA Goddard and employing lasers researchers from government, university and industrial labs is nearing the conclusion of its planned 5 year duration. This paper will describe some of the efforts and results obtained by the Goddard half of the program.

High Intensity Laser Power Beaming Architecture for Space and Terrestrial Missions

Science.gov (United States)

Nayfeh, Taysir; Fast, Brian; Raible, Daniel; Dinca, Dragos; Tollis, Nick; Jalics, Andrew

2011-01-01

High Intensity Laser Power Beaming (HILPB) has been developed as a technique to achieve Wireless Power Transmission (WPT) for both space and terrestrial applications. In this paper, the system architecture and hardware results for a terrestrial application of HILPB are presented. These results demonstrate continuous conversion of high intensity optical energy at near-IR wavelengths directly to electrical energy at output power levels as high as 6.24 W from the single cell 0.8 cm2 aperture receiver. These results are scalable, and may be realized by implementing receiver arraying and utilizing higher power source lasers. This type of system would enable long range optical refueling of electric platforms, such as MUAV s, airships, robotic exploration missions and provide power to spacecraft platforms which may utilize it to drive electric means of propulsion.

High Efficiency Mask Based Laser Materials Processing with TEA-CO2 - and Excimer Laser

DEFF Research Database (Denmark)

Bastue, Jens; Olsen, Flemmming Ove

1997-01-01

In general, mask based laser materials processing techniques suffer from a very low energy efficiency. We have developed a simple device called an energy enhancer, which is capable of increasing the energy efficiency of typical mask based laser materials processing systems. A short review of the ...... line marking with TEA-CO2 laser of high speed canning lines. The second one is manufactured for marking or microdrilling with excimer laser....

A Low Cost 3D Acquiring System for Mushroom Robot Based on Webcam and Line Laser

Directory of Open Access Journals (Sweden)

Gang Sun

2014-03-01

Full Text Available This paper presents a low cost 3D acquiring system for mushroom robot based on webcam and line laser. The system comprises Webcam, semiconductor line laser, motion platform and data process unit. The system can get the 3D information of the Pleurotus eryngii in bottle based on structured light scanning theory. Field test shows the accuracy of the height is less than 2mm and it can be use to locate the buds in the bottle correctly. It has the potention to fulfill the requirement of the location of the mushroom for thinning bud robot.

Combined raman/laser-induced breakdown spectrometer: space and non-space applications

NARCIS (Netherlands)

Sandtke, M.; Laan, E.C.; Ahlers, B.

2010-01-01

TNO has developed the combination of two spectroscopic analysis methods in one instrument. Raman spectroscopy and Laser-induced Breakdown Spectroscopy (LIBS) were brought together for an instrument to be flown on the ExoMars mission from the European Space Agency (ESA) to investigate the Martian

A digital frequency stabilization system of external cavity diode laser based on LabVIEW FPGA

Science.gov (United States)

Liu, Zhuohuan; Hu, Zhaohui; Qi, Lu; Wang, Tao

2015-10-01

Frequency stabilization for external cavity diode laser has played an important role in physics research. Many laser frequency locking solutions have been proposed by researchers. Traditionally, the locking process was accomplished by analog system, which has fast feedback control response speed. However, analog system is susceptible to the effects of environment. In order to improve the automation level and reliability of the frequency stabilization system, we take a grating-feedback external cavity diode laser as the laser source and set up a digital frequency stabilization system based on National Instrument's FPGA (NI FPGA). The system consists of a saturated absorption frequency stabilization of beam path, a differential photoelectric detector, a NI FPGA board and a host computer. Many functions, such as piezoelectric transducer (PZT) sweeping, atomic saturation absorption signal acquisition, signal peak identification, error signal obtaining and laser PZT voltage feedback controlling, are totally completed by LabVIEW FPGA program. Compared with the analog system, the system built by the logic gate circuits, performs stable and reliable. User interface programmed by LabVIEW is friendly. Besides, benefited from the characteristics of reconfiguration, the LabVIEW program is good at transplanting in other NI FPGA boards. Most of all, the system periodically checks the error signal. Once the abnormal error signal is detected, FPGA will restart frequency stabilization process without manual control. Through detecting the fluctuation of error signal of the atomic saturation absorption spectrum line in the frequency locking state, we can infer that the laser frequency stability can reach 1MHz.

Laser system using ultra-short laser pulses

Science.gov (United States)

Dantus, Marcos [Okemos, MI; Lozovoy, Vadim V [Okemos, MI; Comstock, Matthew [Milford, MI

2009-10-27

A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal.

COTS low-cost 622-Mb/s free-space laser communications link for short-distance commercial applications

Science.gov (United States)

Morrison, Kenneth A.

2000-05-01

The results from a low cost 622 Mb/s, free-space laser communication link operating at 850 nm for short distance commercial applications is presented. The test results demonstrate the use of a free-space laser communications transceiver for building to building applications such as LAN, WAN and ATM operations, etc. This illustrates the potential for wide-use commercial computer network applications. The transceiver is constructed of commercial off-the-shelf materials for the development of a low-cost laser communications data link. The test system configuration utilizes standard Personal Computers with network cards and signal conversion cards for the copper to optical medical conversion. These tests precede the development of an increased data rate device operating at 2.5 Gb/s.

The Theory of Random Laser Systems

International Nuclear Information System (INIS)

Xunya Jiang

2002-01-01

Studies of random laser systems are a new direction with promising potential applications and theoretical interest. The research is based on the theories of localization and laser physics. So far, the research shows that there are random lasing modes inside the systems which is quite different from the common laser systems. From the properties of the random lasing modes, they can understand the phenomena observed in the experiments, such as multi-peak and anisotropic spectrum, lasing mode number saturation, mode competition and dynamic processes, etc. To summarize, this dissertation has contributed the following in the study of random laser systems: (1) by comparing the Lamb theory with the Letokhov theory, the general formulas of the threshold length or gain of random laser systems were obtained; (2) they pointed out the vital weakness of previous time-independent methods in random laser research; (3) a new model which includes the FDTD method and the semi-classical laser theory. The solutions of this model provided an explanation of the experimental results of multi-peak and anisotropic emission spectra, predicted the saturation of lasing modes number and the length of localized lasing modes; (4) theoretical (Lamb theory) and numerical (FDTD and transfer-matrix calculation) studies of the origin of localized lasing modes in the random laser systems; and (5) proposal of using random lasing modes as a new path to study wave localization in random systems and prediction of the lasing threshold discontinuity at mobility edge

Time biases in laser ranging observations: A concerning issue of Space Geodesy

Science.gov (United States)

Exertier, Pierre; Belli, A.; Lemoine, J. M.

2017-09-01

Time transfer by Laser Ranging (LR) recently demonstrated a remarkable stability (a few ps over ∼1000 s) and accuracy (synchronizing both space and ground clocks over distances from a few thousands to tens of thousands kilometers. Given its potential role in navigation, fundamental physics and metrology, it is crucial that synergy between laser ranging and Time&Frequency (T/F) technologies improves to meet the present and future space geodesy requirements. In this article, we examine the behavior of T/F systems that are used in LR tracking stations of the international laser ranging service. The approach we investigate is to compute time synchronization between clocks used at LR stations using accurate data of the Time Transfer by Laser Link (T2L2) experiment onboard the satellite Jason-2 (Samain et al., 2014). Systematic time biases are estimated against the UTC time scale for a set of 22 observing stations in 2013, in the range of zero to a few μ s. Our results suggest that the ILRS network suffers from accuracy issues, due to time biases in the laser ranging observations. We discuss how these systematic effects impact the precise orbit determination of LAGEOS geodetic satellites over a 1-year analysis, and additionally give a measure of the local effect into station coordinates, regarding in particular the effect in the east-west component that is of 2-6 mm for a typical systematic time bias of one μ s.

Precedent Research on Compact Laser-plasma based Gantry for Cancer Therapy

International Nuclear Information System (INIS)

Hee, Park Seong; Jeong, Young Uk; Lee, Ki Tae; Kim, Kyung Nam; Cha, Young Ho

2012-03-01

This is the precedent R and D to develop the technology of next generation compact particle cancer treatment system based on laser-plasma interaction and to deduce a big project. The subject of this project are the survey of application technology of laser-plasma based particle beam and the design of compact laser-plasma based gantry. The survey of characteristic of particle beam for cancer therapy and present status can be adapted to develop new system. The comparison between particle beams from the existing system and new one based on laser-plasma acceleration will be important to new design and design optimization. The project includes design of multi-dimensional laser transfer beamline, minimization of laser-plasma acceleration chamber, design of effective energy separation/selection system, and radiation safety and local shielding

Greater vertical spot spacing to improve femtosecond laser capsulotomy quality.

Science.gov (United States)

Schultz, Tim; Joachim, Stephanie C; Noristani, Rozina; Scott, Wendell; Dick, H Burkhard

2017-03-01

To evaluate the effect of adapted capsulotomy laser settings on the cutting quality in femtosecond laser-assisted cataract surgery. Ruhr-University Eye Clinic, Bochum, Germany. Prospective randomized case series. Eyes were treated with 1 of 2 laser settings. In Group 1, the regular standard settings were used (incisional depth 600 μm, pulse energy 4 μJ, horizontal spot spacing 5 μm, vertical spot spacing 10 μm, treatment time 1.2 seconds). In Group 2, vertical spot spacing was increased to 15 μm and the treatment time was 1.0 seconds. Light microscopy was used to evaluate the cut quality of the capsule edge. The size and number of tags (misplaced laser spots, which form a second cut of the capsule with high tear risk) were evaluated in a blinded manner. Groups were compared using the Mann-Whitney U test. The study comprised 100 eyes (50 eyes in each group). Cataract surgery was successfully completed in all eyes, and no anterior capsule tear occurred during the treatment. Histologically, significant fewer tags were observed with the new capsulotomy laser setting. The mean score for the number and size of free tags was significantly lower in this group than with the standard settings (P laser settings improved cut quality and reduced the number of tags. The modification has the potential to reduce the risk for radial capsule tears in femtosecond laser-assisted cataract surgery. With the new settings, no tags and no capsule tears were observed under the operating microscope in any eye. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Department of Defense high power laser program guidance

Science.gov (United States)

Muller, Clifford H.

1994-06-01

The DoD investment of nominally $200 million per year is focused on four high power laser (HPL) concepts: Space-Based Laser (SBL), a Ballistic Missile Defense Organization effort that addresses boost-phase intercept for Theater Missile Defense and National Missile Defense; Airborne Laser (ABL), an Air Force effort that addresses boost-phase intercept for Theater Missile Defense; Ground-Based Laser (GBL), an Air Force effort addressing space control; and Anti-Ship Missile Defense (ASMD), a Navy effort addressing ship-based defense. Each organization is also supporting technology development with the goal of achieving less expensive, brighter, and lighter high power laser systems. These activities represent the building blocks of the DoD program to exploit the compelling characteristics of the high power laser. Even though DoD's HPL program are focused and moderately strong, additional emphasis in a few technical areas could help reduce risk in these programs. In addition, a number of options are available for continuing to use the High-Energy Laser System Test Facility (HELSTF) at White Sands Missile Range. This report provides a brief overview and guidance for the five efforts which comprise the DoD HPL program (SBL, ABL, GBL, ASMD, HELSTF).

Robot-laser system

International Nuclear Information System (INIS)

Akeel, H.A.

1987-01-01

A robot-laser system is described for providing a laser beam at a desired location, the system comprising: a laser beam source; a robot including a plurality of movable parts including a hollow robot arm having a central axis along which the laser source directs the laser beam; at least one mirror for reflecting the laser beam from the source to the desired location, the mirror being mounted within the robot arm to move therewith and relative thereto to about a transverse axis that extends angularly to the central axis of the robot arm; and an automatic programmable control system for automatically moving the mirror about the transverse axis relative to and in synchronization with movement of the robot arm to thereby direct the laser beam to the desired location as the arm is moved

A Technology Demonstration Experiment for Laser Cooled Atomic Clocks in Space

Science.gov (United States)

Klipstein, W. M.; Kohel, J.; Seidel, D. J.; Thompson, R. J.; Maleki, L.; Gibble, K.

2000-01-01

We have been developing a laser-cooling apparatus for flight on the International Space Station (ISS), with the intention of demonstrating linewidths on the cesium clock transition narrower than can be realized on the ground. GLACE (the Glovebox Laser- cooled Atomic Clock Experiment) is scheduled for launch on Utilization Flight 3 (UF3) in 2002, and will be mounted in one of the ISS Glovebox platforms for an anticipated 2-3 week run. Separate flight definition projects funded at NIST and Yale by the Micro- gravity Research Division of NASA as a part of its Laser Cooling and Atomic Physics (LCAP) program will follow GLACE. Core technologies for these and other LCAP missions are being developed at JPL, with the current emphasis on developing components such as the laser and optics subsystem, and non-magnetic vacuum-compatible mechanical shutters. Significant technical challenges in developing a space qualifiable laser cooling apparatus include reducing the volume, mass, and power requirements, while increasing the ruggedness and reliability in order to both withstand typical launch conditions and achieve several months of unattended operation. This work was performed at the Jet Propulsion Laboratory under a contract with the National Aeronautics and Space Administration.

Study and Development of a Laser Based Alignment System

CERN Multimedia

Stern, G

2014-01-01

CLIC (Compact Linear Collider) has tight requirements regarding pre-alignment of beam related components: 10 µm accuracy over a sliding window of 200 m along the 20 km of linac. To perform such an alignment, a new system is proposed combining laser beam as straight line reference and camera/shutter assemblies as sensors. The poster describes the alignment system and shows results regarding laser pointing stability with respect to time, shutter type, distance and environment. These results give a frame for future building and calibrating of sensors.

Note: Reliable and non-contact 6D motion tracking system based on 2D laser scanners for cargo transportation

Energy Technology Data Exchange (ETDEWEB)

Kim, Young-Keun, E-mail: ykkim@handong.edu [Department of Mechanical and Control Engineering, Handong Global University, Pohang (Korea, Republic of); Kim, Kyung-Soo [Department of Mechanical Engineering, KAIST, Daejeon 305-701 (Korea, Republic of)

2014-10-15

Maritime transportation demands an accurate measurement system to track the motion of oscillating container boxes in real time. However, it is a challenge to design a sensor system that can provide both reliable and non-contact methods of 6-DOF motion measurements of a remote object for outdoor applications. In the paper, a sensor system based on two 2D laser scanners is proposed for detecting the relative 6-DOF motion of a crane load in real time. Even without implementing a camera, the proposed system can detect the motion of a remote object using four laser beam points. Because it is a laser-based sensor, the system is expected to be highly robust to sea weather conditions.

Energy enhancer for mask based laser materials processing

DEFF Research Database (Denmark)

Bastue, Jens; Olsen, Flemmming Ove

1996-01-01

A device capable of drastically improving the energy efficiency of present mask based laser materials processing systems is presented. Good accordance between experiments and simulations for a TEA-CO2 laser system designed for laser marking has been demonstrated. The energy efficiency may...... be improved with a factor of 2 - 4 for typical mask transmittances between 10 - 40%....

Tunable Laser Development for In-flight Fiber Optic Based Structural Health Monitoring Systems

Science.gov (United States)

Richards, Lance; Parker, Allen; Chan, Patrick

2014-01-01

The objective of this task is to investigate, develop, and demonstrate a low-cost swept lasing light source for NASA DFRC's fiber optics sensing system (FOSS) to perform structural health monitoring on current and future aerospace vehicles. This is the regular update of the Tunable Laser Development for In-flight Fiber Optic Based Structural Health Monitoring Systems website.

Rule-Based Analytic Asset Management for Space Exploration Systems (RAMSES), Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Payload Systems Inc. (PSI) and the Massachusetts Institute of Technology (MIT) were selected to jointly develop the Rule-based Analytic Asset Management for Space...

Laser Spot Detection Based on Reaction Diffusion

OpenAIRE

Alejandro Vázquez-Otero; Danila Khikhlukha; J. M. Solano-Altamirano; Raquel Dormido; Natividad Duro

2016-01-01

Center-location of a laser spot is a problem of interest when the laser is used for processing and performing measurements. Measurement quality depends on correctly determining the location of the laser spot. Hence, improving and proposing algorithms for the correct location of the spots are fundamental issues in laser-based measurements. In this paper we introduce a Reaction Diffusion (RD) system as the main computational framework for robustly finding laser spot centers. The method presente...

High-power green diode laser systems for biomedical applications

DEFF Research Database (Denmark)

Müller, André

propagation parameters and therefore efficiently increases the brightness of compact and cost-effective diode laser systems. The condition of overlapping beams is an ideal scenario for subsequent frequency conversion. Based on sum-frequency generation of two beam combined diode lasers a 3.2 fold increase...... output power of frequency doubled single emitters is limited by thermal effects potentially resulting in laser degradation and failure. In this work new concepts for power scaling of visible diode laser systems are introduced that help to overcome current limitations and enhance the application potential....... Implementing the developed concept of frequency converted, beam combined diode laser systems will help to overcome the high pump thresholds for ultrabroad bandwidth titanium sapphire lasers, leading towards diode based high-resolution optical coherence tomography with enhanced image quality. In their entirety...

Special Relativity Corrections for Space-Based Lidars

Science.gov (United States)

RaoGudimetla, Venkata S.; Kavaya, Michael J.

1999-01-01

The theory of special relativity is used to analyze some of the physical phenomena associated with space-based coherent Doppler lidars aimed at Earth and the atmosphere. Two important cases of diffuse scattering and retroreflection by lidar targets are treated. For the case of diffuse scattering, we show that for a coaligned transmitter and receiver on the moving satellite, there is no angle between transmitted and returned radiation. However, the ray that enters the receiver does not correspond to a retroreflected ray by the target. For the retroreflection case there is misalignment between the transmitted ray and the received ray. In addition, the Doppler shift in the frequency and the amount of tip for the receiver aperture when needed are calculated, The error in estimating wind because of the Doppler shift in the frequency due to special relativity effects is examined. The results are then applied to a proposed space-based pulsed coherent Doppler lidar at NASA's Marshall Space Flight Center for wind and aerosol backscatter measurements. The lidar uses an orbiting spacecraft with a pulsed laser source and measures the Doppler shift between the transmitted and the received frequencies to determine the atmospheric wind velocities. We show that the special relativity effects are small for the proposed system.

Digital Communication System Based on Polarization Self-Modulation in Lasers

Science.gov (United States)

Tabarin, V. A.; Ikonnikov, V. P.; Shatalov, A. N.

2014-09-01

Polarization self-modulation in lasers can be used to create instruments for generating optical pulses at very high repetition rates without using high-speed electronics. Self-oscillation is observed when part of the output of a laser is returned to the laser after a 90° polarization change. A practical scheme based on polarization self-modulation in a 3.39-μm helium-neon laser is proposed for pulsed code data transmission with an yttrium-iron garnet magnetooptical Q-switch. Highly efficient transmission of digital signals is implemented with a repetition rate of 75 MHz, equivalent to half the free spectral range of the laser.

Characterization of a FBG sensor interrogation system based on a mode-locked laser scheme.

Science.gov (United States)

Madrigal, Javier; Fraile-Peláez, Francisco Javier; Zheng, Di; Barrera, David; Sales, Salvador

2017-10-02

This paper is focused on the characterization of a fiber Bragg grating (FBG) sensor interrogation system based on a fiber ring laser with a semiconductor optical amplifier as the gain medium, and an in-loop electro-optical modulator. This system operates as a switchable active (pulsed) mode-locked laser. The operation principle of the system is explained theoretically and validated experimentally. The ability of the system to interrogate an array of different FBGs in wavelength and spatial domain is demonstrated. Simultaneously, the influence of several important parameters on the performance of the interrogation technique has been investigated. Specifically, the effects of the bandwidth and the reflectivity of the FBGs, the SOA gain, and the depth of the intensity modulation have been addressed.

Laser beam welding quality monitoring system based in high-speed (10 kHz) uncooled MWIR imaging sensors

Science.gov (United States)

Linares, Rodrigo; Vergara, German; Gutiérrez, Raúl; Fernández, Carlos; Villamayor, Víctor; Gómez, Luis; González-Camino, Maria; Baldasano, Arturo; Castro, G.; Arias, R.; Lapido, Y.; Rodríguez, J.; Romero, Pablo

2015-05-01

The combination of flexibility, productivity, precision and zero-defect manufacturing in future laser-based equipment are a major challenge that faces this enabling technology. New sensors for online monitoring and real-time control of laserbased processes are necessary for improving products quality and increasing manufacture yields. New approaches to fully automate processes towards zero-defect manufacturing demand smarter heads where lasers, optics, actuators, sensors and electronics will be integrated in a unique compact and affordable device. Many defects arising in laser-based manufacturing processes come from instabilities in the dynamics of the laser process. Temperature and heat dynamics are key parameters to be monitored. Low cost infrared imagers with high-speed of response will constitute the next generation of sensors to be implemented in future monitoring and control systems for laser-based processes, capable to provide simultaneous information about heat dynamics and spatial distribution. This work describes the result of using an innovative low-cost high-speed infrared imager based on the first quantum infrared imager monolithically integrated with Si-CMOS ROIC of the market. The sensor is able to provide low resolution images at frame rates up to 10 KHz in uncooled operation at the same cost as traditional infrared spot detectors. In order to demonstrate the capabilities of the new sensor technology, a low-cost camera was assembled on a standard production laser welding head, allowing to register melting pool images at frame rates of 10 kHz. In addition, a specific software was developed for defect detection and classification. Multiple laser welding processes were recorded with the aim to study the performance of the system and its application to the real-time monitoring of laser welding processes. During the experiments, different types of defects were produced and monitored. The classifier was fed with the experimental images obtained. Self

Solar pumping of solid state lasers for space mission: a novel approach

Science.gov (United States)

Boetti, N. G.; Lousteau, J.; Negro, D.; Mura, E.; Scarpignato, G. C.; Perrone, G.; Milanese, D.; Abrate, S.

2017-11-01

Solar pumped laser (SPL) can find wide applications in space missions, especially for long lasting ones. In this paper a new technological approach for the realization of a SPL based on fiber laser technology is proposed. We present a preliminary study, focused on the active material performance evaluation, towards the realization of a Nd3+ -doped fiber laser made of phosphate glass materials, emitting at 1.06 μm. For this research several Nd3+ -doped phosphate glass samples were fabricated, with concentration of Nd3+ up to 10 mol%. Physical and thermal properties of the glasses were measured and their spectroscopic properties are described. The effect of Nd3+ doping concentration on emission spectra and lifetimes was investigated in order to study the concentration quenching effect on luminescence performance.

COHERENT LIDAR SYSTEM BASED ON A SEMICONDUCTOR LASER AND AMPLIFIER

DEFF Research Database (Denmark)

2009-01-01

The present invention relates to a compact, reliable and low-cost coherent LIDAR (Light Detection And Ranging) system for remote wind-speed determination, determination of particle concentration, and/or temperature based on an all semiconductor light source and related methods. The present...... invention provides a coherent LIDAR system comprising a semiconductor laser for emission of a measurement beam of electromagnetic radiation directed towards a measurement volume for illumination of particles in the measurement volume, a reference beam generator for generation of a reference beam, a detector...... for generation of a detector signal by mixing of the reference beam with light emitted from the particles in the measurement volume illuminated by the measurement beam, and a signal processor for generating a velocity signal corresponding to the velocity of the particles based on the detector signal....

Laser cutting system

Science.gov (United States)

Dougherty, Thomas J

2015-03-03

A workpiece cutting apparatus includes a laser source, a first suction system, and a first finger configured to guide a workpiece as it moves past the laser source. The first finger includes a first end provided adjacent a point where a laser from the laser source cuts the workpiece, and the first end of the first finger includes an aperture in fluid communication with the first suction system.

A novel diode laser system for photodynamic therapy

DEFF Research Database (Denmark)

Samsøe, E.; Andersen, P. E.; Petersen, P.

2001-01-01

In this paper a novel diode laser system for photodynamic therapy is demonstrated. The system is based on linear spatial filtering and optical phase conjugate feedback from a photorefractive BaTiO3 crystal. The spatial coherence properties of the diode laser are significantly improved. The system...

Infrared-laser-based fundus angiography

Science.gov (United States)

Klingbeil, Ulrich; Canter, Joseph M.; Lesiecki, Michael L.; Reichel, Elias

1994-06-01

Infrared fundus angiography, using the fluorescent dye indocyanine green (ICG), has shown great potential in delineating choroidal neovascularization (CNV) otherwise not detectable. A digital retinal imaging system containing a diode laser for illumination has been developed and optimized to perform high sensitivity ICG angiography. The system requires less power and generates less pseudo-fluorescence background than nonlaser devices. During clinical evaluation at three retinal centers more than 200 patients, the majority of which had age-related macular degeneration, were analyzed. Laser based ICG angiography was successful in outlining many of the ill-defined or obscure CNV as defined by fluorescein angiography. The procedure was not as successful with classic CNV. ICG angiograms were used to prepare and guide laser treatment.

A New Laser Based Approach for Measuring Atmospheric Greenhouse Gases

Directory of Open Access Journals (Sweden)

Jeremy Dobler

2013-11-01

Full Text Available In 2012, we developed a proof-of-concept system for a new open-path laser absorption spectrometer concept for measuring atmospheric CO2. The measurement approach utilizes high-reliability all-fiber-based, continuous-wave laser technology, along with a unique all-digital lock-in amplifier method that, together, enables simultaneous transmission and reception of multiple fixed wavelengths of light. This new technique, which utilizes very little transmitted energy relative to conventional lidar systems, provides high signal-to-noise (SNR measurements, even in the presence of a large background signal. This proof-of-concept system, tested in both a laboratory environment and a limited number of field experiments over path lengths of 680 m and 1,600 m, demonstrated SNR values >1,000 for received signals of ~18 picoWatts averaged over 60 s. A SNR of 1,000 is equivalent to a measurement precision of ±0.001 or ~0.4 ppmv. The measurement method is expected to provide new capability for automated monitoring of greenhouse gas at fixed sites, such as carbon sequestration facilities, volcanoes, the short- and long-term assessment of urban plumes, and other similar applications. In addition, this concept enables active measurements of column amounts from a geosynchronous orbit for a network of ground-based receivers/stations that would complement other current and planned space-based measurement capabilities.

Studying stellar binary systems with the Laser Interferometer Space Antenna using delayed rejection Markov chain Monte Carlo methods

International Nuclear Information System (INIS)

Trias, Miquel; Vecchio, Alberto; Veitch, John

2009-01-01

Bayesian analysis of Laser Interferometer Space Antenna (LISA) data sets based on Markov chain Monte Carlo methods has been shown to be a challenging problem, in part due to the complicated structure of the likelihood function consisting of several isolated local maxima that dramatically reduces the efficiency of the sampling techniques. Here we introduce a new fully Markovian algorithm, a delayed rejection Metropolis-Hastings Markov chain Monte Carlo method, to efficiently explore these kind of structures and we demonstrate its performance on selected LISA data sets containing a known number of stellar-mass binary signals embedded in Gaussian stationary noise.

Coherent Doppler Laser Radar: Technology Development and Applications

Science.gov (United States)

Kavaya, Michael J.; Arnold, James E. (Technical Monitor)

2000-01-01

NASA's Marshall Space Flight Center has been investigating, developing, and applying coherent Doppler laser radar technology for over 30 years. These efforts have included the first wind measurement in 1967, the first airborne flights in 1972, the first airborne wind field mapping in 1981, and the first measurement of hurricane eyewall winds in 1998. A parallel effort at MSFC since 1982 has been the study, modeling and technology development for a space-based global wind measurement system. These endeavors to date have resulted in compact, robust, eyesafe lidars at 2 micron wavelength based on solid-state laser technology; in a factor of 6 volume reduction in near diffraction limited, space-qualifiable telescopes; in sophisticated airborne scanners with full platform motion subtraction; in local oscillator lasers capable of rapid tuning of 25 GHz for removal of relative laser radar to target velocities over a 25 km/s range; in performance prediction theory and simulations that have been validated experimentally; and in extensive field campaign experience. We have also begun efforts to dramatically improve the fundamental photon efficiency of the laser radar, to demonstrate advanced lower mass laser radar telescopes and scanners; to develop laser and laser radar system alignment maintenance technologies; and to greatly improve the electrical efficiency, cooling technique, and robustness of the pulsed laser. This coherent Doppler laser radar technology is suitable for high resolution, high accuracy wind mapping; for aerosol and cloud measurement; for Differential Absorption Lidar (DIAL) measurements of atmospheric and trace gases; for hard target range and velocity measurement; and for hard target vibration spectra measurement. It is also suitable for a number of aircraft operations applications such as clear air turbulence (CAT) detection; dangerous wind shear (microburst) detection; airspeed, angle of attack, and sideslip measurement; and fuel savings through

A new three-dimensional nonscanning laser imaging system based on the illumination pattern of a point-light-source array

Science.gov (United States)

Xia, Wenze; Ma, Yayun; Han, Shaokun; Wang, Yulin; Liu, Fei; Zhai, Yu

2018-06-01

One of the most important goals of research on three-dimensional nonscanning laser imaging systems is the improvement of the illumination system. In this paper, a new three-dimensional nonscanning laser imaging system based on the illumination pattern of a point-light-source array is proposed. This array is obtained using a fiber array connected to a laser array with each unit laser having independent control circuits. This system uses a point-to-point imaging process, which is realized using the exact corresponding optical relationship between the point-light-source array and a linear-mode avalanche photodiode array detector. The complete working process of this system is explained in detail, and the mathematical model of this system containing four equations is established. A simulated contrast experiment and two real contrast experiments which use the simplified setup without a laser array are performed. The final results demonstrate that unlike a conventional three-dimensional nonscanning laser imaging system, the proposed system meets all the requirements of an eligible illumination system. Finally, the imaging performance of this system is analyzed under defocusing situations, and analytical results show that the system has good defocusing robustness and can be easily adjusted in real applications.

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.

Miniature fiber-optic multiphoton microscopy system using frequency-doubled femtosecond Er-doped fiber laser.

Science.gov (United States)

Huang, Lin; Mills, Arthur K; Zhao, Yuan; Jones, David J; Tang, Shuo

2016-05-01

We report on a miniature fiber-optic multiphoton microscopy (MPM) system based on a frequency-doubled femtosecond Er-doped fiber laser. The femtosecond pulses from the laser source are delivered to the miniature fiber-optic probe at 1.58 µm wavelength, where a standard single mode fiber is used for delivery without the need of free-space dispersion compensation components. The beam is frequency-doubled inside the probe by a periodically poled MgO:LiNbO3 crystal. Frequency-doubled pulses at 786 nm with a maximum power of 80 mW and a pulsewidth of 150 fs are obtained and applied to excite intrinsic signals from tissues. A MEMS scanner, a miniature objective, and a multimode collection fiber are further used to make the probe compact. The miniature fiber-optic MPM system is highly portable and robust. Ex vivo multiphoton imaging of mammalian skins demonstrates the capability of the system in imaging biological tissues. The results show that the miniature fiber-optic MPM system using frequency-doubled femtosecond fiber laser can potentially bring the MPM imaging for clinical applications.

Laser-Based Maintenance and Repair Technologies for Reactor Components

International Nuclear Information System (INIS)

Masaki Yoda; Naruhiko Mukai; Makoto Ochiai; Masataka Tamura; Satoshi Okada; Katsuhiko Sato; Motohiko Kimura; Yuji Sano; Noboru Saito; Seishi Shima; Tetsuo Yamamoto

2004-01-01

Toshiba has developed various laser-based maintenance and repair technologies and applied them to existing nuclear power plants. Laser-based technology is considered to be the best tool for remote processing in nuclear power plants, and particularly so for the maintenance and repair of reactor core components. Accessibility could be drastically improved by a simple handling system owing to the absence of reactive force against laser irradiation and the flexible optical fiber. For the preventive maintenance, laser peening (LP) technology was developed and applied to reactor components in operating BWR plants. LP is a novel process to improve residual stress from tensile to compressive on material surface layer by irradiating focused high-power laser pulses in water. We have developed a fiber-delivered LP system as a preventive maintenance measure against stress corrosion cracking (SCC). Laser ultrasonic testing (LUT) has a great potential to be applied to the remote inspection of reactor components. Laser-induced surface acoustic wave (SAW) inspection system was developed using a compact probe with a multi-mode optical fiber and an interferometer. The developed system successfully detected a micro slit of 0.5 mm depth on weld metal and heat-affected zone (HAZ). An artificial SCC was also detected by the system. We are developing a new LP system combined with LUT to treat the inner surface of bottom-mounted instruments (BMI) of PWR plants. Underwater laser seal welding (LSW) technology was also developed to apply surface crack. LSW is expected to isolate the crack tip from corrosive water environment and to stop the propagation of the crack. Rapid heating and cooling of the process minimize the heat effect, which extends the applicability to neutron-irradiated material. This paper describes recent advances in the development and application of such laser-based technologies. (authors)

Space Launch System Base Heating Test: Experimental Operations & Results

Science.gov (United States)

Dufrene, Aaron; Mehta, Manish; MacLean, Matthew; Seaford, Mark; Holden, Michael

2016-01-01

NASA's Space Launch System (SLS) uses four clustered liquid rocket engines along with two solid rocket boosters. The interaction between all six rocket exhaust plumes will produce a complex and severe thermal environment in the base of the vehicle. This work focuses on a recent 2% scale, hot-fire SLS base heating test. These base heating tests are short-duration tests executed with chamber pressures near the full-scale values with gaseous hydrogen/oxygen engines and RSRMV analogous solid propellant motors. The LENS II shock tunnel/Ludwieg tube tunnel was used at or near flight duplicated conditions up to Mach 5. Model development was based on the Space Shuttle base heating tests with several improvements including doubling of the maximum chamber pressures and duplication of freestream conditions. Test methodology and conditions are presented, and base heating results from 76 runs are reported in non-dimensional form. Regions of high heating are identified and comparisons of various configuration and conditions are highlighted. Base pressure and radiometer results are also reported.

Development of automatic pre-tracking system for fillet weld based on laser trigonometry

Science.gov (United States)

Shen, Xiaoqin; Yu, Fusheng

2005-01-01

In this paper, an automatic fillet weld pre-tracking system for welding the work piece of lorry back boards with several bend in haul automobile is developed basing on laser trigonometry. The optical measuring head based on laser-PSD trigonometry is used as position sensor. It is placed in front of the traveling direction of welding wire to get the distances from welding wire to the two side boards of the welding lines, upper board and bottom board of the fillet weld respectively. A chip of AT89S52 is used as the micro controller in this system. The AC servomotors, ball-screws and straight guide rails constitute the sliding table to take welding wire move. The laser-PSD sensors pass through the vertical board, upper board and bottom board of the fillet weld when welding wire moves and then get the distance. The laser-PSD sensors output the analog signals. After A/D conversion, the digital signal is input into AT89S52 and calculated. Then the information of the position and lateral deviation of the welding wire when welding a certain position are gotten to control welding wires. So the weld pre-tracking for welding the work piece with long distance and large bend in haul automobile is realized. The position information is input into EEPROM to be saved for short time after handled by AT89S52. The information is as the welding position information as well as the speed adjusting data of the welding wire when it welds the several bend of the work piece. The practice indicates that this system has high pre-tracking precision, good anti-disturb ability, excellent reliability, easy operating ability and good adaptability to the field of production.

Influence of spatial beam inhomogeneities on the parameters of a petawatt laser system based on multi-stage parametric amplification

International Nuclear Information System (INIS)

Frolov, S A; Trunov, V I; Pestryakov, Efim V; Leshchenko, V E

2013-01-01

We have developed a technique for investigating the evolution of spatial inhomogeneities in high-power laser systems based on multi-stage parametric amplification. A linearised model of the inhomogeneity development is first devised for parametric amplification with the small-scale self-focusing taken into account. It is shown that the application of this model gives the results consistent (with high accuracy and in a wide range of inhomogeneity parameters) with the calculation without approximations. Using the linearised model, we have analysed the development of spatial inhomogeneities in a petawatt laser system based on multi-stage parametric amplification, developed at the Institute of Laser Physics, Siberian Branch of the Russian Academy of Sciences (ILP SB RAS). (control of laser radiation parameters)

Laser source for dimensional metrology: investigation of an iodine stabilized system based on narrow linewidth 633 nm DBR diode

Science.gov (United States)

Rerucha, Simon; Yacoot, Andrew; Pham, Tuan M.; Cizek, Martin; Hucl, Vaclav; Lazar, Josef; Cip, Ondrej

2017-04-01

We demonstrated that an iodine stabilized distributed Bragg reflector (DBR) diode based laser system lasing at a wavelength in close proximity to λ =633 nm could be used as an alternative laser source to the helium-neon lasers in both scientific and industrial metrology. This yields additional advantages besides the optical frequency stability and coherence: inherent traceability, wider optical frequency tuning range, higher output power and high frequency modulation capability. We experimentally investigated the characteristics of the laser source in two major steps: first using a wavelength meter referenced to a frequency comb controlled with a hydrogen maser and then on an interferometric optical bench testbed where we compared the performance of the laser system with that of a traditional frequency stabilized He-Ne laser. The results indicate that DBR diode laser system provides a good laser source for applications in dimensional (nano)metrology, especially in conjunction with novel interferometric detection methods exploiting high frequency modulation or multiaxis measurement systems.

Application of Various Lasers to Laser Trimming Resistance System

Institute of Scientific and Technical Information of China (English)

SUN Ji-feng

2007-01-01

Though the laser trimming resistance has been an old laser machining industry for over 30 years, the development of technology brings new alternative lasers which can be used for the traditional machining. The paper describes application of various lasers to laser trimming resistance system including early traditional krypton arc lamp pumped Nd:YAG to laser, modern popular diode pumped solid state laser and the present advanced harmonic diode pumped solid state laser. Using the new alternative lasers in the laser trimming resistance system can dramatically improve the yields and equipment performance.

Exploration of a capability-focused aerospace system of systems architecture alternative with bilayer design space, based on RST-SOM algorithmic methods.

Science.gov (United States)

Li, Zhifei; Qin, Dongliang; Yang, Feng

2014-01-01

In defense related programs, the use of capability-based analysis, design, and acquisition has been significant. In order to confront one of the most challenging features of a huge design space in capability based analysis (CBA), a literature review of design space exploration was first examined. Then, in the process of an aerospace system of systems design space exploration, a bilayer mapping method was put forward, based on the existing experimental and operating data. Finally, the feasibility of the foregoing approach was demonstrated with an illustrative example. With the data mining RST (rough sets theory) and SOM (self-organized mapping) techniques, the alternative to the aerospace system of systems architecture was mapping from P-space (performance space) to C-space (configuration space), and then from C-space to D-space (design space), respectively. Ultimately, the performance space was mapped to the design space, which completed the exploration and preliminary reduction of the entire design space. This method provides a computational analysis and implementation scheme for large-scale simulation.

Dual-wavelength high-power diode laser system based on an external-cavity tapered amplifier with tunable frequency difference

DEFF Research Database (Denmark)

Chi, Mingjun; Jensen, Ole Bjarlin; Petersen, Paul Michael

2012-01-01

knowledge, this is the broadest tuning range of the frequency difference from a dual-wavelength diode laser system. The spectrum, output power, and beam quality of the diode laser system are characterized. The power stability of each wavelength is measured, and the power fluctuations of the two wavelengths......A dual-wavelength high-power semiconductor laser system based on a tapered amplifier with double-Littrow external cavity is demonstrated around 800 nm. The two wavelengths can be tuned individually, and the frequency difference of the two wavelengths is tunable from 0.5 to 10.0 THz. To our...

The fault monitoring and diagnosis knowledge-based system for space power systems: AMPERES, phase 1

Science.gov (United States)

Lee, S. C.

1989-01-01

The objective is to develop a real time fault monitoring and diagnosis knowledge-based system (KBS) for space power systems which can save costly operational manpower and can achieve more reliable space power system operation. The proposed KBS was developed using the Autonomously Managed Power System (AMPS) test facility currently installed at NASA Marshall Space Flight Center (MSFC), but the basic approach taken for this project could be applicable for other space power systems. The proposed KBS is entitled Autonomously Managed Power-System Extendible Real-time Expert System (AMPERES). In Phase 1 the emphasis was put on the design of the overall KBS, the identification of the basic research required, the initial performance of the research, and the development of a prototype KBS. In Phase 2, emphasis is put on the completion of the research initiated in Phase 1, and the enhancement of the prototype KBS developed in Phase 1. This enhancement is intended to achieve a working real time KBS incorporated with the NASA space power system test facilities. Three major research areas were identified and progress was made in each area. These areas are real time data acquisition and its supporting data structure; sensor value validations; development of inference scheme for effective fault monitoring and diagnosis, and its supporting knowledge representation scheme.

High power lasers & systems

OpenAIRE

Chatwin, Chris; Young, Rupert; Birch, Philip

2015-01-01

Some laser history;\\ud Airborne Laser Testbed & Chemical Oxygen Iodine Laser (COIL);\\ud Laser modes and beam propagation;\\ud Fibre lasers and applications;\\ud US Navy Laser system – NRL 33kW fibre laser;\\ud Lockheed Martin 30kW fibre laser;\\ud Conclusions

Nuclear-pumped lasers

CERN Document Server

Prelas, Mark

2016-01-01

This book focuses on Nuclear-Pumped Laser (NPL) technology and provides the reader with a fundamental understanding of NPLs, a review of research in the field, and exploration of large scale NPL system design and applications. Early chapters look at the fundamental properties of lasers, nuclear-pumping and nuclear reactions that may be used as drivers for nuclear-pumped lasers. The book goes on to explore the efficient transport of energy from the ionizing radiation to the laser medium and then the operational characteristics of existing nuclear-pumped lasers. Models based on Mathematica, explanations and a tutorial all assist the reader’s understanding of this technology. Later chapters consider the integration of the various systems involved in NPLs and the ways in which they can be used, including beyond the military agenda. As readers will discover, there are significant humanitarian applications for high energy/power lasers, such as deflecting asteroids, space propulsion, power transmission and mining....

Influence of laser frequency noise on scanning Fabry-Perot interferometer based laser Doppler velocimetry

DEFF Research Database (Denmark)

Rodrigo, Peter John; Pedersen, Christian

2014-01-01

n this work, we study the performance of a scanning Fabry-Perot interferometer based laser Doppler velocimeter (sFPILDV) and compare two candidate 1.5 um single-frequency laser sources for the system – a fiber laser (FL) and a semiconductor laser (SL). We describe a straightforward calibration...... procedure for the sFPI-LDV and investigate the effect of different degrees of laser frequency noise between the FL and the SL on the velocimeter’s performance...

Aerosol core nuclear reactor for space-based high energy/power nuclear-pumped lasers

International Nuclear Information System (INIS)

Prelas, M.A.; Boody, F.P.; Zediker, M.S.

1987-01-01

An aerosol core reactor concept can overcome the efficiency and/or chemical activity problems of other fuel-reactant interface concepts. In the design of a laser using the nuclear energy for a photon-intermediate pumping scheme, several features of the aerosol core reactor concept are attractive. First, the photon-intermediate pumping concept coupled with photon concentration methods and the aerosol fuel can provide the high power densities required to drive high energy/power lasers efficiently (about 25 to 100 kW/cu cm). Secondly, the intermediate photons should have relatively large mean free paths in the aerosol fuel which will allow the concept to scale more favorably. Finally, the aerosol core reactor concept can use materials which should allow the system to operate at high temperatures. An excimer laser pumped by the photons created in the fluorescer driven by a self-critical aerosol core reactor would have reasonable dimensions (finite cylinder of height 245 cm and radius of 245 cm), reasonable laser energy (1 MJ in approximately a 1 millisecond pulse), and reasonable mass (21 kg uranium, 8280 kg moderator, 460 kg fluorescer, 450 kg laser medium, and 3233 kg reflector). 12 references

Laser electro-optic system for rapid three-dimensional /3-D/ topographic mapping of surfaces

Science.gov (United States)

Altschuler, M. D.; Altschuler, B. R.; Taboada, J.

1981-01-01

It is pointed out that the generic utility of a robot in a factory/assembly environment could be substantially enhanced by providing a vision capability to the robot. A standard videocamera for robot vision provides a two-dimensional image which contains insufficient information for a detailed three-dimensional reconstruction of an object. Approaches which supply the additional information needed for the three-dimensional mapping of objects with complex surface shapes are briefly considered and a description is presented of a laser-based system which can provide three-dimensional vision to a robot. The system consists of a laser beam array generator, an optical image recorder, and software for controlling the required operations. The projection of a laser beam array onto a surface produces a dot pattern image which is viewed from one or more suitable perspectives. Attention is given to the mathematical method employed, the space coding technique, the approaches used for obtaining the transformation parameters, the optics for laser beam array generation, the hardware for beam array coding, and aspects of image acquisition.

Wavefront Tilt And Beam Walk Correction For A Pulsed Laser System

Science.gov (United States)

Bartosewcz, Mike; Tyburski, Joe

1986-05-01

The Lockheed Beam Alignment Assembly (BAA) is designed to be a space qualifiable, long life, low bandwidth beam stabilization system. The BAA will stabilize a wandering pulsed laser beam with an input beam tilt of ±750 microradians and translation of ±2.5 mm by two orders of magnitude at the bandwidth of interest. A bandwidth of three hertz was selected to remove laser and optical train thermal drifts and launch induced strain effects. The lambda over twenty RMS wavefront will be maintained in the optics at full power under vacuum test, to demonstrate space qualifiability and optical performance.

A noncontact laser system for measuring soil surface topography

International Nuclear Information System (INIS)

Huang, C.; White, I.; Thwaite, E.G.; Bendeli, A.

1988-01-01

Soil surface topography profoundly influences runoff hydrodynamics, soil erosion, and surface retention of water. Here we describe an optical noncontact system for measuring soil surface topography. Soil elevation is measured by projecting a laser beam onto the surface and detecting the position of the interception point. The optical axis of the detection system is oriented at a small angle to the incident beam. A low-power HeNe (Helium-Neon) laser is used as the laser source, a photodiode array is used as the laser image detector and an ordinary 35-mm single lens reflex camera provides the optical system to focus the laser image onto the diode array. A wide spectrum of measurement ranges (R) and resolutions are selectable, from 1 mm to 1 m. These are determined by the laser-camera distance and angle, the focal length of the lens, and the sensing length of the diode array and the number of elements (N) contained in the array. The resolution of the system is approximately R/2N. We show for the system used here that this resolution is approximately 0.2%. In the configuration selected, elevation changes of 0.16 mm could be detected over a surface elevation range of 87 mm. The sampling rate of the system is 1000 Hz, which permits soil surfaces to be measured at speeds of up to 1 m s −1 with measurements taken at 1-mm spacing. Measurements of individual raindrop impacts on the soil and of soil surfaces before and after rain show the versatility of the laser surface profiler, which has applications in studies of erosion processes, surface storage and soil trafficability

Laser transmitter system

International Nuclear Information System (INIS)

Dye, R.A.

1975-01-01

A laser transmitter system is disclosed which utilizes mechanical energy for generating an output pulse. The laser system includes a current developing device such as a piezoelectric crystal which charges a storage device such as a capacitor in response to a mechanical input signal. The capacitor is coupled to a switching device, such as a silicon controlled rectifier (SCR). The switching device is coupled to a laser transmitter such as a GaAs laser diode, which provides an output signal in response to the capacitor being discharged

A NASA high-power space-based laser research and applications program

Science.gov (United States)

Deyoung, R. J.; Walberg, G. D.; Conway, E. J.; Jones, L. W.

1983-01-01

Applications of high power lasers are discussed which might fulfill the needs of NASA missions, and the technology characteristics of laser research programs are outlined. The status of the NASA programs or lasers, laser receivers, and laser propulsion is discussed, and recommendations are presented for a proposed expanded NASA program in these areas. Program elements that are critical are discussed in detail.

Electrically pumped graphene-based Landau-level laser

Science.gov (United States)

Brem, Samuel; Wendler, Florian; Winnerl, Stephan; Malic, Ermin

2018-03-01

Graphene exhibits a nonequidistant Landau quantization with tunable Landau-level (LL) transitions in the technologically desired terahertz spectral range. Here, we present a strategy for an electrically driven terahertz laser based on Landau-quantized graphene as the gain medium. Performing microscopic modeling of the coupled electron, phonon, and photon dynamics in such a laser, we reveal that an inter-LL population inversion can be achieved resulting in the emission of coherent terahertz radiation. The presented paper provides a concrete recipe for the experimental realization of tunable graphene-based terahertz laser systems.

Optical system for UV-laser technological equipment

Science.gov (United States)

Fedosov, Yuri V.; Romanova, Galina E.; Afanasev, Maxim Ya.

2017-09-01

Recently there has been an intensive development of intelligent industrial equipment that is highly automated and can be rapidly adjusted for certain details. This equipment can be robotics systems, automatic wrappers and markers, CNC machines and 3D printers. The work equipment considered is the system for selective curing of photopolymers using a UV-laser and UV-radiation in such equipment that leads to additional technical difficulties. In many cases for transporting the radiation from the laser to the point processed, a multi-mirror system is used: however, such systems are usually difficult to adjust. Additionally, such multi-mirror systems are usually used as a part of the equipment for laser cutting of metals using high-power IR-lasers. For the UV-lasers, using many mirrors leads to crucial radiation losses because of many reflections. Therefore, during the development of the optical system for technological equipment using UV-laser we need to solve two main problems: to transfer the radiation for the working point with minimum losses and to include the system for controlling/handling the radiation spot position. We introduce a system for working with UV-lasers with 450mW of power and a wavelength of 0.45 μm based on a fiber system. In our modelling and design, we achieve spot sizes of about 300 μm, and the designed optical and mechanical systems (prototypes) were manufactured and assembled. In this paper, we present the layout of the technological unit, the results of the theoretical modelling of some parts of the system and some experimental results.

The Laser Alignment System for the CMS silicon strip tracker

CERN Document Server

Olzem, Jan

2009-01-01

The Laser Alignment System (LAS) of the CMS silicon strip Tracker has been designed for surveying the geometry of the large-scale Tracker support structures. It uses 40 laser beams ($\\lambda$ = 1075 nm) that induce signals on a subset of the Tracker silicon sensors. The positions in space of the laser spots on the sensors are reconstructed with a resolution of 30 $\\mu$m. From this, the LAS is capable of permanent in-time monitoring of the different Tracker components relative to each other with better than 30 $\\mu$m precision. Additionally, it can provide an absolute measurement of the Tracker mechanical structure with an accuracy better than 70 $\\mu$m, thereby supplying additional input to the track based alignment at detector startup. 31 out of the 40 LAS beams have been successfully operated during the CMS cosmic muon data taking campaign in autumn 2008. The alignment of the Tracker Endcap Discs and of the discs with respect to the Tracker Inner Barrel and Tracker Outer Barrel subdetectors was measured w...

Laser display system for multi-depth screen projection scenarios.

Science.gov (United States)

La Torre, J Pablo; Mayes, Nathan; Riza, Nabeel A

2017-11-10

Proposed is a laser projection display system that uses an electronically controlled variable focus lens (ECVFL) to achieve sharp and in-focus image projection over multi-distance three-dimensional (3D) conformal screens. The system also functions as an embedded distance sensor that enables 3D mapping of the multi-level screen platform before the desired laser scanned beam focused/defocused projected spot sizes are matched to the different localized screen distances on the 3D screen. Compared to conventional laser scanning and spatial light modulator (SLM) based projection systems, the proposed design offers in-focus non-distorted projection over a multi-distance screen zone with varying depths. An experimental projection system for a screen depth variation of 65 cm is demonstrated using a 633 nm laser beam, 3 KHz scan speed galvo-scanning mirrors, and a liquid-based ECVFL. As a basic demonstration, an in-house developed MATLAB based graphic user interface is deployed to work along with the laser projection display, enabling user inputs like text strings or predefined image projection. The user can specify projection screen distance, scanned laser linewidth, projected text font size, projected image dimensions, and laser scanning rate. Projected images are shown highlighting the 3D control capabilities of the display, including the production of a non-distorted image onto two-depths versus a distorted image via dominant prior-art projection methods.

The C3PO project: a laser communication system concept for small satellites

Science.gov (United States)

d'Humières, Benoît; Esmiller, Bruno; Gouy, Yann; Steck, Emilie; Quintana, Crisanto; Faulkner, Graham; O'Brien, Dominic; Sproll, Fabian; Wagner, Paul; Hampf, Daniel; Riede, Wolfgang; Salter, Michael; Wang, Qin; Platt, Duncan; Jakonis, Darius; Piao, Xiaoyu; Karlsson, Mikael; Oberg, Olof; Petermann, Ingemar; Michalkiewicz, Aneta; Krezel, Jerzy; Debowska, Anna; Thueux, Yoann

2017-02-01

The satellite market is shifting towards smaller (micro and nanosatellites), lowered mass and increased performance platforms. Nanosatellites and picosatellites have been used for a number of new, innovative and unique payloads and missions. This trend requires new concepts for a reduced size, a better performance/weight ratio and a reduction of onboard power consumption. In this context, disruptive technologies, such as laser-optical communication systems, are opening new possibilities. This paper presents the C3PO1 system, "advanced Concept for laser uplink/ downlink CommuniCation with sPace Objects", and the first results of the development of its key technologies. This project targets the design of a communications system that uses a ground-based laser to illuminate a satellite, and a Modulating Retro-Reflector (MRR) to return a beam of light modulated by data to the ground. This enables a downlink, without a laser source on the satellite. This architecture suits well to small satellite applications so as high data rates are potentially provided with very low board mass. C3PO project aims to achieve data rates of 1Gbit/s between LEO satellites and Earth with a communication payload mass of less than 1kilogram. In this paper, results of the initial experiments and demonstration of the key technologies will be shown.

Visualization of the influence of the air conditioning system to the high-power laser beam quality with the modulation coherent imaging method.

Science.gov (United States)

Tao, Hua; Veetil, Suhas P; Pan, Xingchen; Liu, Cheng; Zhu, Jianqiang

2015-08-01

Air conditioning systems can lead to dynamic phase change in the laser beams of high-power laser facilities for the inertial confinement fusion, and this kind of phase change cannot be measured by most of the commonly employed Hartmann wavefront sensor or interferometry due to some uncontrollable factors, such as too large laser beam diameters and the limited space of the facility. It is demonstrated that this problem can be solved using a scheme based on modulation coherent imaging, and thus the influence of the air conditioning system on the performance of the high-power facility can be evaluated directly.

Target isolation system, high power laser and laser peening method and system using same

Science.gov (United States)

Dane, C. Brent; Hackel, Lloyd A.; Harris, Fritz

2007-11-06

A system for applying a laser beam to work pieces, includes a laser system producing a high power output beam. Target delivery optics are arranged to deliver the output beam to a target work piece. A relay telescope having a telescope focal point is placed in the beam path between the laser system and the target delivery optics. The relay telescope relays an image between an image location near the output of the laser system and an image location near the target delivery optics. A baffle is placed at the telescope focal point between the target delivery optics and the laser system to block reflections from the target in the target delivery optics from returning to the laser system and causing damage.

Electron beam test of key elements of the laser-based calibration system for the muon g - 2 experiment

Energy Technology Data Exchange (ETDEWEB)

Anastasi, A., E-mail: antonioanastasi89@gmail.com [Laboratori Nazionali Frascati dell' INFN, Via E. Fermi 40, 00044 Frascati (Italy); Dipartimento MIFT, Università di Messina, Messina (Italy); Basti, A.; Bedeschi, F.; Bartolini, M. [INFN, Sezione di Pisa (Italy); Cantatore, G. [INFN, Sezione di Trieste e G.C. di Udine (Italy); Università di Trieste, Trieste (Italy); Cauz, D. [INFN, Sezione di Trieste e G.C. di Udine (Italy); Università di Udine, Udine (Italy); Corradi, G. [Laboratori Nazionali Frascati dell' INFN, Via E. Fermi 40, 00044 Frascati (Italy); Dabagov, S. [Laboratori Nazionali Frascati dell' INFN, Via E. Fermi 40, 00044 Frascati (Italy); Lebedev Physical Institute and NRNU MEPhI, Moscow (Russian Federation); Di Sciascio, G. [INFN, Sezione di Roma Tor Vergata, Roma (Italy); Di Stefano, R. [INFN, Sezione di Napoli (Italy); Università di Cassino, Cassino (Italy); Driutti, A. [INFN, Sezione di Trieste e G.C. di Udine (Italy); Università di Udine, Udine (Italy); Escalante, O. [Università di Napoli, Napoli (Italy); Ferrari, C. [Laboratori Nazionali Frascati dell' INFN, Via E. Fermi 40, 00044 Frascati (Italy); Istituto Nazionale di Ottica del C.N.R., UOS Pisa, via Moruzzi 1, 56124, Pisa (Italy); Fienberg, A.T. [University of Washington, Box 351560, Seattle, WA 98195 (United States); Fioretti, A.; Gabbanini, C. [Laboratori Nazionali Frascati dell' INFN, Via E. Fermi 40, 00044 Frascati (Italy); Istituto Nazionale di Ottica del C.N.R., UOS Pisa, via Moruzzi 1, 56124, Pisa (Italy); Gioiosa, A. [INFN, Sezione di Lecce (Italy); Università del Molise, Pesche (Italy); Hampai, D. [Laboratori Nazionali Frascati dell' INFN, Via E. Fermi 40, 00044 Frascati (Italy); Hertzog, D.W. [University of Washington, Box 351560, Seattle, WA 98195 (United States); and others

2017-01-11

We report the test of many of the key elements of the laser-based calibration system for muon g - 2 experiment E989 at Fermilab. The test was performed at the Laboratori Nazionali di Frascati's Beam Test Facility using a 450 MeV electron beam impinging on a small subset of the final g - 2 lead-fluoride crystal calorimeter system. The calibration system was configured as planned for the E989 experiment and uses the same type of laser and most of the final optical elements. We show results regarding the calorimeter's response calibration, the maximum equivalent electron energy which can be provided by the laser and the stability of the calibration system components.

Electron beam test of key elements of the laser-based calibration system for the muon g - 2 experiment

Energy Technology Data Exchange (ETDEWEB)

Anastasi, A.; Basti, A.; Bedeschi, F.; Bartolini, M.; Cantatore, G.; Cauz, D.; Corradi, G.; Dabagov, S.; Di Sciascio, G.; Di Stefano, R.; Driutti, A.; Escalante, O.; Ferrari, C.; Fienberg, A. T.; Fioretti, A.; Gabbanini, C.; Gioiosa, A.; Hampai, D.; Hertzog, D. W.; Iacovacci, M.; Karuza, M.; Kaspar, J.; Liedl, A.; Lusiani, A.; Marignetti, F.; Mastroianni, S.; Moricciani, D.; Pauletta, G.; Piacentino, G. M.; Raha, N.; Rossi, E.; Santi, L.; Venanzoni, G.

2017-01-01

We report the test of many of the key elements of the laser-based calibration system for muon g - 2 experiment E989 at Fermilab. The test was performed at the Laboratori Nazionali di Frascati's Beam Test Facility using a 450 MeV electron beam impinging on a small subset of the final g - 2 lead-fluoride crystal calorimeter system. The calibration system was configured as planned for the E989 experiment and uses the same type of laser and most of the final optical elements. We show results regarding the calorimeter's response calibration, the maximum equivalent electron energy which can be provided by the laser and the stability of the calibration system components.

Graphene devices based on laser scribing technology

Science.gov (United States)

Qiao, Yan-Cong; Wei, Yu-Hong; Pang, Yu; Li, Yu-Xing; Wang, Dan-Yang; Li, Yu-Tao; Deng, Ning-Qin; Wang, Xue-Feng; Zhang, Hai-Nan; Wang, Qian; Yang, Zhen; Tao, Lu-Qi; Tian, He; Yang, Yi; Ren, Tian-Ling

2018-04-01

Graphene with excellent electronic, thermal, optical, and mechanical properties has great potential applications. The current devices based on graphene grown by micromechanical exfoliation, chemical vapor deposition (CVD), and thermal decomposition of silicon carbide are still expensive and inefficient. Laser scribing technology, a low-cost and time-efficient method of fabricating graphene, is introduced in this review. The patterning of graphene can be directly performed on solid and flexible substrates. Therefore, many novel devices such as strain sensors, acoustic devices, memory devices based on laser scribing graphene are fabricated. The outlook and challenges of laser scribing technology have also been discussed. Laser scribing may be a potential way of fabricating wearable and integrated graphene systems in the future.

LabVIEW-based X-ray detection system for laser compton scattering experiment

International Nuclear Information System (INIS)

Luo Wen; Xu Wang; Pan Qiangyan

2010-01-01

A LabVIEW-based X-ray detection system has been developed for laser-Compton scattering (LCS) experiment at the 100 MeV Linac of the Shanghai Institute of Applied Physics (SINAP). It mainly consists of a Si (Li) detector, readout electronics and a LabVIEW-based Data Acquisition (DAQ), and possesses the functions of signal spectrum displaying, acquisition control and simple online data analysis and so on. The performance test shows that energy and time resolutions of the system are 184 eV at 5.9 keV and ≤ 1% respectively and system instability is found to be 0.3‰ within a week. As a result, this X-ray detection system has low-cost and high-performance features and can meet the requirements of LCS experiment. (authors)

Noether's Theorem and its Inverse of Birkhoffian System in Event Space Based on Herglotz Variational Problem

Science.gov (United States)

Tian, X.; Zhang, Y.

2018-03-01

Herglotz variational principle, in which the functional is defined by a differential equation, generalizes the classical ones defining the functional by an integral. The principle gives a variational principle description of nonconservative systems even when the Lagrangian is independent of time. This paper focuses on studying the Noether's theorem and its inverse of a Birkhoffian system in event space based on the Herglotz variational problem. Firstly, according to the Herglotz variational principle of a Birkhoffian system, the principle of a Birkhoffian system in event space is established. Secondly, its parametric equations and two basic formulae for the variation of Pfaff-Herglotz action of a Birkhoffian system in event space are obtained. Furthermore, the definition and criteria of Noether symmetry of the Birkhoffian system in event space based on the Herglotz variational problem are given. Then, according to the relationship between the Noether symmetry and conserved quantity, the Noether's theorem is derived. Under classical conditions, Noether's theorem of a Birkhoffian system in event space based on the Herglotz variational problem reduces to the classical ones. In addition, Noether's inverse theorem of the Birkhoffian system in event space based on the Herglotz variational problem is also obtained. In the end of the paper, an example is given to illustrate the application of the results.

A Laser-Based Diagnostic Suite for Hypersonic Test Facilities, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — In this SBIR effort, Los Gatos Research (LGR) proposes to develop a suite of laser-based diagnostics for the study of reactive and non-reactive hypersonic flows....

Technology Development of a Fiber Optic-Coupled Laser Ignition System for Multi-Combustor Rocket Engines

Science.gov (United States)

Trinh, Huu P.; Early, Jim; Osborne, Robin; Thomas, Matthew E.; Bossard, John A.

2002-01-01

This paper addresses the progress of technology development of a laser ignition system at NASA Marshall Space Flight Center (MSFC). The first two years of the project focus on comprehensive assessments and evaluations of a novel dual-pulse laser concept, flight- qualified laser system, and the technology required to integrate the laser ignition system to a rocket chamber. With collaborations of the Department of Energy/Los Alamos National Laboratory (LANL) and CFD Research Corporation (CFDRC), MSFC has conducted 26 hot fire ignition tests with lab-scale laser systems. These tests demonstrate the concept feasibility of dual-pulse laser ignition to initiate gaseous oxygen (GOX)/liquid kerosene (RP-1) combustion in a rocket chamber. Presently, a fiber optic- coupled miniaturized laser ignition prototype is being implemented at the rocket chamber test rig for future testing. Future work is guided by a technology road map that outlines the work required for maturing a laser ignition system. This road map defines activities for the next six years, with the goal of developing a flight-ready laser ignition system.

Analysis of remote operating systems for space-based servicing operations, volume 1

Science.gov (United States)

1985-01-01

A two phase study was conducted to analyze and develop the requirements for remote operating systems as applied to space based operations for the servicing, maintenance, and repair of satellites. Phase one consisted of the development of servicing requirements to establish design criteria for remote operating systems. Phase two defined preferred system concepts and development plans which met the requirements established in phase one. The specific tasks in phase two were to: (1) identify desirable operational and conceptual approaches for selected mission scenarios; (2) examine the potential impact of remote operating systems incorporated into the design of the space station; (3) address remote operating systems design issues, such as mobility, which are effected by the space station configuration; and (4) define the programmatic approaches for technology development, testing, simulation, and flight demonstration.

The e-Beam Sustained Laser Technology for Space-based Doppler Wind Lidar

Science.gov (United States)

Brown, M. J.; Holman, W.; Robinson, R. J.; Schwarzenberger, P. M.; Smith, I. M.; Wallace, S.; Harris, M. R.; Willetts, D. V.; Kurzius, S. C.

1992-01-01

An overview is presented of GEC Avionics activities relating to the Spaceborne Doppler Wind Lidar. In particular, the results of design studies into the use of an e-beam sustained CO2 laser for spaceborne applications, and experimental work on a test bed system are discussed.

Chaotic dynamics and chaos control in nonlinear laser systems

International Nuclear Information System (INIS)

Fang Jinqing; Yao Weiguang

2001-01-01

Chaotic dynamics and chaos control have become a great challenge in nonlinear laser systems and its advances are reviewed mainly based on the ring cavity laser systems. The principle and stability conditions for time-delay feedback control are analyzed and applied to chaos control in the laser systems. Other advanced methods of chaos control, such as weak spatial perturbation and occasional proportional feedback technique, are discussed. Prospects of chaos control for application (such as improvement of laser power and performance, synchronized chaos secure communication and information processing) are pointed out finally

Mathematical modeling of a photovoltaic-laser energy converter for iodine laser radiation

Science.gov (United States)

Walker, Gilbert H.; Heinbockel, John H.

1987-01-01

Space-based laser power systems will require converters to change laser radiation into electricity. Vertical junction photovoltaic converters are promising devices for this use. A promising laser for the laser power station is the t-C4F9I laser which emits radiation at a wavelength of 1.315 microns. This paper describes the results of mathematical modeling of a photovoltaic-laser energy converter for use with this laser. The material for this photovoltaic converter is Ga(53)In(47)As which has a bandgap energy of 0.94 eV, slightly below the energy of the laser photons (0.943 eV). Results of a study optimizing the converter parameters are presented. Calculated efficiency for a 1000 vertical junction converter is 42.5 percent at a power density of 1 x 10 to the 3d power w/sq cm.

Laser-plasma based electron acceleration studies planned at CAT, Indore

International Nuclear Information System (INIS)

Naik, P.A.; Gupta, P.D.

2005-01-01

The Laser Plasma Division at the Centre for Advanced Technology is engaged in a variety of R and D activities on laser-plasma interaction with special emphasis on laser-matter interaction at ultra-high intensities. An important aspect of our future work is studies in laser-plasma based acceleration using an elaborate infrastructural set-up of ultra-fast laser and plasma diagnostic systems and recently acquired 10 TW, 50 fs Ti: Sapphire laser system. This paper presents outline of the planned studies in this field. (author)

SU-F-J-44: Development of a Room Laser Based Real-Time Alignment Monitoring System Using An Array of Photodiodes

International Nuclear Information System (INIS)

Noh, Y; Kim, T; Kang, S; Kim, D; Cho, M; Kim, K; Shin, D; Suh, T; Kim, S

2016-01-01

Purpose: To develop a real-time alignment monitoring system (RAMS) to compensate for the limitations of the conventional room laser based alignment system, and to verify the feasibility of the RAMS. Methods: The RAMS was composed of a room laser sensing array (RLSA), an analog-todigital converter, and a control PC. In the RLSA, seven photodiodes (each in 1 mm width) are arranged in a pattern that the RAMS provides alignment in 1 mm resolution. It works based on detecting laser light aligned on one of photodiodes. When misaligned, the laser would match with different photodiode(s) giving signal at unexpected location. Thus, how much displaced can be determined. To verify the reproducibility of the system with respect to time as well as repeated set-ups, temporal reproducibility and repeatability test was conducted. The accuracy of the system was tested by obtaining detection signals with varying laser-match positions. Results: The signal of the RAMS was found to be stable with respect to time. The repeatability test resulted in a maximum coefficient of variance of 1.14%, suggesting that the signal of the RAMS was stable over repeated set-ups. In the accuracy test, signals between when the laser was aligned and notaligned with any of sensors could be distinguished by signal intensity. The signals of not-aligned sensors were always below 75% of the signal of the aligned sensor. It was confirmed that the system could detect 1 mm of movement by monitoring the pattern of signals, and could observe the movement of the system in real-time. Conclusion: We developed a room laser based alignment monitoring system. The feasibility test verified that the system is capable of quantitative alignment monitoring in real time. The system is relatively simple, not expensive, and considered to be easily incorporated into conventional room laser systems for real-time alignment monitoring. This research was supported by the Mid-career Researcher Program through NRF funded by the

Analysis of Nd3+:glass, solar-pumped, high-powr laser systems

Science.gov (United States)

Zapata, L. E.; Williams, M. D.

1989-01-01

The operating characteristics of Nd(3+):glass lasers energized by a solar concentrator were analyzed for the hosts YAG, silicate glass, and phosphate glass. The modeling is based on the slab zigzag laser geometry and assumes that chemical hardening methods for glass are successful in increasing glass hardness by a factor of 4. On this basis, it was found that a realistic 1-MW solar-pumped laser might be constructed from phosphate glass 4 sq m in area and 2 mm thick. If YAG were the host medium, a 1-MW solar-pumped laser need only be 0.5 sq m in area and 0.5 cm thick, which is already possible. In addition, Nd(3+) doped glass fibers were found to be excellent solar-pumped laser candidates. The small diameter of fibers eliminates thermal stress problems, and if their diameter is kept small (10 microns), they propagate a Gaussian single mode which can be expanded and transmitted long distances in space. Fiber lasers could then be used for communications in space or could be bundled and the individual beams summed or phase-matched for high-power operation.

A modular Space Station/Base electrical power system - Requirements and design study.

Science.gov (United States)

Eliason, J. T.; Adkisson, W. B.

1972-01-01

The requirements and procedures necessary for definition and specification of an electrical power system (EPS) for the future space station are discussed herein. The considered space station EPS consists of a replaceable main power module with self-contained auxiliary power, guidance, control, and communication subsystems. This independent power source may 'plug into' a space station module which has its own electrical distribution, control, power conditioning, and auxiliary power subsystems. Integration problems are discussed, and a transmission system selected with local floor-by-floor power conditioning and distribution in the station module. This technique eliminates the need for an immediate long range decision on the ultimate space base power sources by providing capability for almost any currently considered option.

Technology development for laser-cooled clocks on the International Space Station

Science.gov (United States)

Klipstein, W. M.

2003-01-01

The PARCS experiment will use a laser-cooled cesium atomic clock operating in the microgravity environment aboard the International Space Station to provide both advanced tests of gravitational theory to demonstrate a new cold-atom clock technology for space.

Multispectral imaging system based on laser-induced fluorescence for security applications

Science.gov (United States)

Caneve, L.; Colao, F.; Del Franco, M.; Palucci, A.; Pistilli, M.; Spizzichino, V.

2016-10-01

The development of portable sensors for fast screening of crime scenes is required to reduce the number of evidences useful to be collected, optimizing time and resources. Laser based spectroscopic techniques are good candidates to this scope due to their capability to operate in field, in remote and rapid way. In this work, the prototype of a multispectral imaging LIF (Laser Induced Fluorescence) system able to detect evidence of different materials on large very crowded and confusing areas at distances up to some tens of meters will be presented. Data collected as both 2D fluorescence images and LIF spectra are suitable to the identification and the localization of the materials of interest. A reduced scan time, preserving at the same time the accuracy of the results, has been taken into account as a main requirement in the system design. An excimer laser with high energy and repetition rate coupled to a gated high sensitivity ICCD assures very good performances for this purpose. Effort has been devoted to speed up the data processing. The system has been tested in outdoor and indoor real scenarios and some results will be reported. Evidence of the plastics polypropylene (PP) and polyethilene (PE) and polyester have been identified and their localization on the examined scenes has been highlighted through the data processing. By suitable emission bands, the instrument can be used for the rapid detection of other material classes (i.e. textiles, woods, varnishes). The activities of this work have been supported by the EU-FP7 FORLAB project (Forensic Laboratory for in-situ evidence analysis in a post blast scenario).

Power beaming providing a space power infrastructure

International Nuclear Information System (INIS)

Bamberger, J.A.; Coomes, E.P.

1992-01-01

This paper, based on two levels of technology maturity, applied the power beaming concept to four panned satellite constellations. The analysis shows that with currently available technology, power beaming can provide mass savings to constellations in orbits ranging from low-Earth orbit to geosynchronous orbit. Two constellations, space surveillance and tracking system and space-based radar, can be supported with current technology. The other two constellations, space-based laser array and boost surveillance and tracking system, will require power and transmission system improvements before their breakeven specific mass is achieved. A doubling of SP-100 conversion efficiency from 10 to 20% would meet or exceed breakeven for these constellations

A field-deployable compound-specific isotope analyzer based on quantum cascade laser and hollow waveguide

Science.gov (United States)

Wu, Sheng; Deev, Andrei

2013-01-01

A field deployable Compound Specific Isotope Analyzer (CSIA) coupled with capillary chromatogrpahy based on Quantum Cascade (QC) lasers and Hollow Waveguide (HWG) with precision and chemical resolution matching mature Mass Spectroscopy has been achieved in our laboratory. The system could realize 0.3 per mil accuracy for 12C/13C for a Gas Chromatography (GC) peak lasting as short as 5 seconds with carbon molar concentration in the GC peak less than 0.5%. Spectroscopic advantages of HWG when working with QC lasers, i.e. single mode transmission, noiseless measurement and small sample volume, are compared with traditional free space and multipass spectroscopy methods.

Development of portable laser peening systems for nuclear power reactors

International Nuclear Information System (INIS)

Chida, Itaru; Uehara, Takuya; Yoda, Masaki; Miyasaka, Hiroyuki; Kato, Hiromi

2009-01-01

Stress corrosion cracking (SCC) is the major factor to reduce the reliability of aged reactor components. Toshiba has developed various laser-based maintenance and repair technologies and applied them to existing nuclear power plants. Laser-based technology is considered to be the best tool for remote processing in nuclear power plants, and particularly so for the maintenance and repair of reactor core components. Accessibility could be drastically improved by a simple handling system owing to the absence of reactive force against laser irradiation and the flexible optical fiber. For the preventive maintenance, laser peening technology was developed and applied to reactor components in operating BWRs and PWRs. Laser peening is a novel process to improve residual stress from tensile to compressive on material surface layer by irradiating focused high-power laser pulses in water without any surface preparations. Laser peening systems, which deliver laser pulses with mirrors or through an optical fiber, were developed and have been applied to preventive maintenance against SCC in nuclear power reactors since 1999. Each system was composed of laser oscillators, a beam delivery system, a laser irradiation head, remote handling equipment and a monitor/control system. Beam delivery with mirrors was accomplished through alignment/tracking functions with sufficient accuracy. Reliable fiber-delivery was attained by the development of a novel input coupling optics and an irradiation head with auto-focusing. Recently, we have developed portable laser peening (PLP) system which could employ both mirror- and fiber- delivery technologies. Size and weight of the PLP system for BWR bottom was almost 1/25 compared to the previous system. PLP system would be the applicable to both BWRs and PWRs as one of the maintenance technologies. (author)

Comparison of laser-based mitigation of fused silica surface damage using mid- versus far-infrared lasers

Energy Technology Data Exchange (ETDEWEB)

Yang, S T; Matthews, M J; Elhadj, S; Cooke, D; Guss, G M; Draggoo, V G; Wegner, P J

2009-12-16

Laser induced growth of optical damage can limit component lifetime and therefore operating costs of large-aperture fusion-class laser systems. While far-infrared (IR) lasers have been used previously to treat laser damage on fused silica optics and render it benign, little is known about the effectiveness of less-absorbing mid-IR lasers for this purpose. In this study, they quantitatively compare the effectiveness and efficiency of mid-IR (4.6 {micro}m) versus far-IR (10.6 {micro}m) lasers in mitigating damage growth on fused silica surfaces. The non-linear volumetric heating due to mid-IR laser absorption is analyzed by solving the heat equation numerically, taking into account the temperature-dependent absorption coefficient {alpha}(T) at {lambda} = 4.6 {micro}m, while far-IR laser heating is well-described by a linear analytic approximation to the laser-driven temperature rise. In both cases, the predicted results agree well with surface temperature measurements based on infrared radiometry, as well as sub-surface fictive temperature measurements based on confocal Raman microscopy. Damage mitigation efficiency is assessed using a figure of merit (FOM) relating the crack healing depth to laser power required, under minimally-ablative conditions. Based on their FOM, they show that for cracks up to at least 500 {micro}m in depth, mitigation with a 4.6 {micro}m mid-IR laser is more efficient than mitigation with a 10.6 {micro}m far-IR laser. This conclusion is corroborated by direct application of each laser system to the mitigation of pulsed laser-induced damage possessing fractures up to 225 {micro}m in depth.

High energy, single frequency, tunable laser source operating in burst mode for space based lidar applications

Science.gov (United States)

Cosentino, Alberto; Mondello, Alessia; Sapia, Adalberto; D'Ottavi, Alessandro; Brotini, Mauro; Nava, Enzo; Stucchi, Emanuele; Trespidi, Franco; Mariottini, Cristina; Wazen, Paul; Falletto, Nicolas; Fruit, Michel

2017-11-01

This paper describes the laser transmitter assembly used in the ALADIN instrument currently in C/D development phase for the ESA ADM-AEOLUS mission (EADS Astrium as prime contractor for the satellite and the instrument). The Laser Transmitter Assembly (TXA), based on a diode pumped tripled Nd:YAG laser, is used to generate tunable laser pulses of 150 mJ at a nominal wavelength of 355 nm. This laser is operated in burst mode, with a pulse repetition cycle of 100 Hz. The TXA is composed of the following units: a diodepumped CW Nd:YAG Laser named Reference Laser Head (RLH), used to inject a diode-pumped, Q-switched, amplified and frequency tripled Nd:YAG Laser working in the third harmonic referred as Power Laser Head (PLH) and a Transmitter Laser Electronics (TLE) containing all the control and power electronics needed for PLH and RLH operation. The TXA is made by an European consortium under the leadership of Galileo Avionica (It), and including CESI (It), Quantel (Fr), TESAT (Ge) and Thales (Fr).

High-Voltage Power Supply System for Laser Isotope Separation

Energy Technology Data Exchange (ETDEWEB)

Ketaily, E.C.; Buckner, R.P.; Uhrik, R.L.

1979-06-26

This report presents several concepts for Laser High-Voltage Power Supply (HVPS) Systems for a Laser Isotope Separation facility. Selection of equipments and their arrangement into operational systems is based on proven designs and on application concepts now being developed. This report has identified a number of alternative system arrangements and has provided preliminary cost estimates for each. The report includes a recommendation for follow-on studies that will further define the optimum Laser HVPS Systems. Brief descriptions are given of Modulator/Regulator circuit trade-offs, system control interfaces, and their impact on costs.

High-Voltage Power Supply System for Laser Isotope Separation

International Nuclear Information System (INIS)

Ketaily, E.C.; Buckner, R.P.; Uhrik, R.L.

1979-01-01

This report presents several concepts for Laser High-Voltage Power Supply (HVPS) Systems for a Laser Isotope Separation facility. Selection of equipments and their arrangement into operational systems is based on proven designs and on application concepts now being developed. This report has identified a number of alternative system arrangements and has provided preliminary cost estimates for each. The report includes a recommendation for follow-on studies that will further define the optimum Laser HVPS Systems. Brief descriptions are given of Modulator/Regulator circuit trade-offs, system control interfaces, and their impact on costs

885-nm laser diode array pumped ceramic Nd:YAG master oscillator power amplifier system

Science.gov (United States)

Yu, Anthony W.; Li, Steven X.; Stephen, Mark A.; Seas, Antonios; Troupaki, Elisavet; Vasilyev, Aleksey; Conley, Heather; Filemyr, Tim; Kirchner, Cynthia; Rosanova, Alberto

2010-04-01

The objective of this effort is to develop more reliable, higher efficiency diode pumped Nd:YAG laser systems for space applications by leveraging technology investments from the DoD and other commercial industries. Our goal is to design, build, test and demonstrate the effectiveness of combining 885 nm laser pump diodes and the use of ceramic Nd:YAG for future flight missions. The significant reduction in thermal loading on the gain medium by the use of 885 nm pump lasers will improve system efficiency.

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.

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.

A digital intensity stabilization system for HeNe laser

Science.gov (United States)

Wei, Zhimeng; Lu, Guangfeng; Yang, Kaiyong; Long, Xingwu; Huang, Yun

2012-02-01

A digital intensity stabilization system for HeNe laser is developed. Based on a switching power IC to design laser power supply and a general purpose microcontroller to realize digital PID control, the system constructs a closed loop to stabilize the laser intensity by regulating its discharge current. The laser tube is made of glass ceramics and its integrated structure is steady enough to eliminate intensity fluctuations at high frequency and attenuates all intensity fluctuations, and this makes it easy to tune the control loop. The control loop between discharge current and photodiode voltage eliminates the long-term drifts. The intensity stability of the HeNe laser with this system is 0.014% over 12 h.

Powering laser diode systems

CERN Document Server

Trestman, Grigoriy A

2017-01-01

This Tutorial Text discusses the competent design and skilled use of laser diode drivers (LDDs) and power supplies (PSs) for the electrical components of laser diode systems. It is intended to help power-electronic design engineers during the initial design stages: the choice of the best PS topology, the calculation of parameters and components of the PS circuit, and the computer simulation of the circuit. Readers who use laser diode systems for research, production, and other purposes will also benefit. The book will help readers avoid errors when creating laser systems from ready-made blocks, as well as understand the nature of the "mystical failures" of laser diodes (and possibly prevent them).

Pump laser-induced space-charge effects in HHG-driven time- and angle-resolved photoelectron spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Oloff, L.-P., E-mail: oloff@physik.uni-kiel.de; Hanff, K.; Stange, A.; Rohde, G.; Diekmann, F.; Bauer, M.; Rossnagel, K., E-mail: rossnagel@physik.uni-kiel.de [Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel (Germany)

2016-06-14

With the advent of ultrashort-pulsed extreme ultraviolet sources, such as free-electron lasers or high-harmonic-generation (HHG) sources, a new research field for photoelectron spectroscopy has opened up in terms of femtosecond time-resolved pump-probe experiments. The impact of the high peak brilliance of these novel sources on photoemission spectra, so-called vacuum space-charge effects caused by the Coulomb interaction among the photoemitted probe electrons, has been studied extensively. However, possible distortions of the energy and momentum distributions of the probe photoelectrons caused by the low photon energy pump pulse due to the nonlinear emission of electrons have not been studied in detail yet. Here, we systematically investigate these pump laser-induced space-charge effects in a HHG-based experiment for the test case of highly oriented pyrolytic graphite. Specifically, we determine how the key parameters of the pump pulse—the excitation density, wavelength, spot size, and emitted electron energy distribution—affect the measured time-dependent energy and momentum distributions of the probe photoelectrons. The results are well reproduced by a simple mean-field model, which could open a path for the correction of pump laser-induced space-charge effects and thus toward probing ultrafast electron dynamics in strongly excited materials.

Effect of paraelectrode processes on contraction of space charge in periodic-pulse lasers

Science.gov (United States)

Arytyunyan, R. V.; Baranov, V. Yu.; Borisov, V. M.; Vinokhodov, A. Yu.; Kiryukhin, Yu. B.

1986-05-01

A characteristic feature of periodic-pulse electric-discharge CO2-lasers and excimer lasers is contraction of the space charge as the pulse repetition rate increases. The emission energy per pulse decreases as a consequence, with the average laser power first ceasing to increase linearly beyond a certain corner repetition rate and then decreasing beyond a certain critical repetition rate. A study of this phenomenon was made, for the purpose of separating the effect of paracathode processes from the effect of gas dynamics and then evaluating the effect of the former alone. Paraelectrode perturbations were simulated by focusing the radiation from the an XeCl-laser on the cathode surface in an atmosphere of nonabsorbing gases. Laser pulses of up to approximately 0.5 J energy and of approximately 50 ns duration were focused within a spot of 1 mm(2) area on a cathode inside a discharge chamber, with the power density of incident radiation regulated by means of an attenuator. A space charge within a volume of 2.5x4.5x9 cm(3) was generated between this specially shaped cathode and a mesh anode with an approximately 50% optical transmission coefficient. The space charge in helium and in neon was photographed, and the time lag of a discharge pulse behind a contracting laser pulse was measured as a function of the laser pulse energy for these two gases, as well as for a He+C12 gas mixture. The general trend was found to be the same in each case, the time lag increasing with increasing energy first at a slower rate up to a critical energy level and then faster. It has been established that plasma does not build up on the cathode before the laser pulse energy reaches 30 mJ (for a 3 mm(2) surface area), while plasma glow begins as the laser pulse energy reaches 150 mJ. A contracted channel begins to form within the laser-cathode interaction space, with an attendant fast increase of the time lag owing to evaporation of the cathode metal.

Infrared laser scattering system for plasma diagnostics

Energy Technology Data Exchange (ETDEWEB)

Muraoka, K; Hiraki, N; Kawasaki, S [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

1975-05-01

The possibility of observing the collective scattering of infrared laser light from plasmas is discussed in terms of the laser power requirement, the necessary optical system and the detector performance, and is shown to be feasible with the present day techniques to get the ion temperature by means of a CO/sub 2/ laser on theta pinch plasmas. Based on this estimate, the construction of the TEA CO/sub 2/ laser and the preparations of the optical components have been started and some preliminary results of these are described.

Infrared laser scattering system for plasma diagnostics

International Nuclear Information System (INIS)

Muraoka, Katsunori; Hiraki, Naoji; Kawasaki, Shoji

1975-01-01

The possibility of observing the collective scattering of infrared laser light from plasmas is discussed in terms of the laser power requirement, the necessary optical system and the detector performance, and is shown to be feasible with the present day techniques to get the ion temperature by means of a CO 2 laser on theta pinch plasmas. Based on this estimate, the construction of the TEA CO 2 laser and the preparations of the optical components have been started and some preliminary results of these are described. (auth.)

State-space modelling for the ejector-based refrigeration system driven by low grade energy

International Nuclear Information System (INIS)

Xue, Binqiang; Cai, Wenjian; Wang, Xinli

2015-01-01

This paper presents a novel global state-space model to describe the ejector-based refrigeration system, which includes the dynamics of the two heat exchangers and the static properties of ejector, compressor and expansion valve. Different from the existing methods, the proposed method introduces some intermediate variables into the dynamic modelling in developing reduced order models of the heat exchangers (evaporator and condenser) based on the Number of Transfer Units (NTU) method. This global model with fewer dimensions is much simpler and can be more convenient for the real-time control system design, compared with other dynamic models. Finally, the proposed state-space model has been validated by dynamic response experiments on the ejector-based refrigeration cycle with refrigerant R134a.The experimental results indicate that the proposed model can predict well the dynamics of the ejector-based refrigeration system. - Highlights: • A low-order state-space model of ejector-based refrigeration system is presented. • Reduced-order models of heat exchangers are developed based on NTU method. • The variations of mass flow rates are introduced in multiple fluid phase regions. • Experimental results show the proposed model has a good performance

Longitudinal space charge assisted echo seeding of a free-electron laser with laser-spoiler noise suppression

Directory of Open Access Journals (Sweden)

Kirsten Hacker

2014-09-01

Full Text Available Seed lasers are employed to improve the temporal coherence of free-electron laser (FEL light. However, when these seed pulses are short relative to the particle bunch, the noisy, temporally incoherent radiation from the unseeded electrons can overwhelm the coherent, seeded radiation. In this paper, a technique to seed a particle bunch with an external laser is presented in which a new mechanism to improve the contrast between coherent and incoherent free electron laser radiation is employed together with a novel, simplified echo-seeding method. The concept relies on a combination of longitudinal space charge wakes and an echo-seeding technique to make a short, coherent pulse of FEL light together with noise background suppression. Several different simulation codes are used to illustrate the concept with conditions at the soft x-ray free-electron laser in Hamburg, FLASH.

Infrared laser system

International Nuclear Information System (INIS)

Cantrell, C.D.; Carbone, R.J.

1977-01-01

An infrared laser system and method for isotope separation may comprise a molecular gas laser oscillator to produce a laser beam at a first wavelength, Raman spin flip means for shifting the laser to a second wavelength, a molecular gas laser amplifier to amplify said second wavelength laser beam to high power, and optical means for directing the second wavelength, high power laser beam against a desired isotope for selective excitation thereof in a mixture with other isotopes. The optical means may include a medium which shifts the second wavelength high power laser beam to a third wavelength, high power laser beam at a wavelength coincidental with a corresponding vibrational state of said isotope and which is different from vibrational states of other isotopes in the gas mixture

A laser-based eye-tracking system.

Science.gov (United States)

Irie, Kenji; Wilson, Bruce A; Jones, Richard D; Bones, Philip J; Anderson, Tim J

2002-11-01

This paper reports on the development of a new eye-tracking system for noninvasive recording of eye movements. The eye tracker uses a flying-spot laser to selectively image landmarks on the eye and, subsequently, measure horizontal, vertical, and torsional eye movements. Considerable work was required to overcome the adverse effects of specular reflection of the flying-spot from the surface of the eye onto the sensing elements of the eye tracker. These effects have been largely overcome, and the eye-tracker has been used to document eye movement abnormalities, such as abnormal torsional pulsion of saccades, in the clinical setting.

SpaceWire- Based Control System Architecture for the Lightweight Advanced Robotic Arm Demonstrator [LARAD

Science.gov (United States)

Rucinski, Marek; Coates, Adam; Montano, Giuseppe; Allouis, Elie; Jameux, David

2015-09-01

The Lightweight Advanced Robotic Arm Demonstrator (LARAD) is a state-of-the-art, two-meter long robotic arm for planetary surface exploration currently being developed by a UK consortium led by Airbus Defence and Space Ltd under contract to the UK Space Agency (CREST-2 programme). LARAD has a modular design, which allows for experimentation with different electronics and control software. The control system architecture includes the on-board computer, control software and firmware, and the communication infrastructure (e.g. data links, switches) connecting on-board computer(s), sensors, actuators and the end-effector. The purpose of the control system is to operate the arm according to pre-defined performance requirements, monitoring its behaviour in real-time and performing safing/recovery actions in case of faults. This paper reports on the results of a recent study about the feasibility of the development and integration of a novel control system architecture for LARAD fully based on the SpaceWire protocol. The current control system architecture is based on the combination of two communication protocols, Ethernet and CAN. The new SpaceWire-based control system will allow for improved monitoring and telecommanding performance thanks to higher communication data rate, allowing for the adoption of advanced control schemes, potentially based on multiple vision sensors, and for the handling of sophisticated end-effectors that require fine control, such as science payloads or robotic hands.

Burr formation detector for fiber laser cutting based on a photodiode sensor system

Science.gov (United States)

Schleier, Max; Adelmann, Benedikt; Neumeier, Benedikt; Hellmann, Ralf

2017-11-01

We report a unique sensor system based on a InGaAs photodiode to detect the formation of burr during near infrared fiber laser cutting. The sensor approach encompasses the measurement of the thermal radiation form the process zone, optical filtering, digitalized sampling at 20 kHz, digital filtering using an elliptical band-pass filter 12th order and calculation of the standard deviation. We find a linear correlation between the deduced sensor signal and the generated burr height with this functionality being experimentally confirmed for laser cutting of mild and stainless steel of different thicknesses. The underlying mechanism of this transducer concept is attributed to the melt flow dynamics inside the cut kerf.

Energy storage and power conditioning system for the Shiva laser

International Nuclear Information System (INIS)

Allen, G.R.; Gagnon, W.L.; Rupert, P.R.; Trenholme, J.B.

1975-01-01

An optimal energy delivery system for the world's largest glass laser system has been designed based on computer modeling and operation of laser hardware. Components of the system have been tested on operating lasers at LLL. The Shiva system is now under construction and will be completed in 1977. The energy supply described here will provide cost-effective, reliable power and facilitate the gathering of data in pursuit of controlled thermonuclear reactions

System performances of optical space code-division multiple-access-based fiber-optic two-dimensional parallel data link.

Science.gov (United States)

Nakamura, M; Kitayama, K

1998-05-10

Optical space code-division multiple access is a scheme to multiplex and link data between two-dimensional processors such as smart pixels and spatial light modulators or arrays of optical sources like vertical-cavity surface-emitting lasers. We examine the multiplexing characteristics of optical space code-division multiple access by using optical orthogonal signature patterns. The probability density function of interference noise in interfering optical orthogonal signature patterns is calculated. The bit-error rate is derived from the result and plotted as a function of receiver threshold, code length, code weight, and number of users. Furthermore, we propose a prethresholding method to suppress the interference noise, and we experimentally verify that the method works effectively in improving system performance.

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.

A LabVIEW-Based Virtual Instrument System for Laser-Induced Fluorescence Spectroscopy.

Science.gov (United States)

Wu, Qijun; Wang, Lufei; Zu, Lily

2011-01-01

We report the design and operation of a Virtual Instrument (VI) system based on LabVIEW 2009 for laser-induced fluorescence experiments. This system achieves synchronous control of equipment and acquisition of real-time fluorescence data communicating with a single computer via GPIB, USB, RS232, and parallel ports. The reported VI system can also accomplish data display, saving, and analysis, and printing the results. The VI system performs sequences of operations automatically, and this system has been successfully applied to obtain the excitation and dispersion spectra of α-methylnaphthalene. The reported VI system opens up new possibilities for researchers and increases the efficiency and precision of experiments. The design and operation of the VI system are described in detail in this paper, and the advantages that this system can provide are highlighted.

Recent results in mirror based high power laser cutting

DEFF Research Database (Denmark)

Olsen, Flemming Ove; Nielsen, Jakob Skov; Elvang, Mads

2004-01-01

In this paper, recent results in high power laser cutting, obtained in reseach and development projects are presented. Two types of mirror based focussing systems for laser cutting have been developed and applied in laser cutting studies on CO2-lasers up to 12 kW. In shipyard environment cutting...... speed increase relative to state-of-the-art cutting of over 100 % has been achieved....

Performance of a high repetition pulse rate laser system for in-gas-jet laser ionization studies with the Leuven laser ion source LISOL

International Nuclear Information System (INIS)

Ferrer, R.; Sonnenschein, V.T.; Bastin, B.; Franchoo, S.; Huyse, M.; Kudryavtsev, Yu.; Kron, T.; Lecesne, N.; Moore, I.D.; Osmond, B.; Pauwels, D.; Radulov, D.; Raeder, S.; Rens, L.

2012-01-01

The laser ionization efficiency of the Leuven gas cell-based laser ion source was investigated under on- and off-line conditions using two distinctly different laser setups: a low-repetition rate dye laser system and a high-repetition rate Ti:sapphire laser system. A systematic study of the ion signal dependence on repetition rate and laser pulse energy was performed in off-line tests using stable cobalt and copper isotopes. These studies also included in-gas-jet laser spectroscopy measurements on the hyperfine structure of 63 Cu. A final run under on-line conditions in which the radioactive isotope 59 Cu (T 1/2 = 81.5 s) was produced, showed a comparable yield of the two laser systems for in-gas-cell ionization. However, a significantly improved time overlap by using the high-repetition rate laser system for in-gas-jet ionization was demonstrated by an increase of the overall duty cycle, and at the same time, pointed to the need for a better shaped atomic jet to reach higher ionization efficiencies.

A Unique Photon Bombardment System for Space Applications

Science.gov (United States)

Klein, E. J.

1993-01-01

The innovative Electromagnetic Radiation Collection and Concentration System (EMRCCS) described is the foundation for the development of a multiplicity of space and terrestrial system formats. The system capability allows its use in the visual, infrared, and ultraviolet ranges of the spectrum for EM collection, concentration, source/receptor tracking, and targeting. The nonimaging modular optical system uses a physically static position aperture for EM radiation collection. Folded optics provide the concentration of the radiation and source autotracking. The collected and concentrated electromagnetic radiation is utilized in many applications, e.g., solar spectrum in thermal and associative photon bombardment applications for hazardous waste management, water purification, metal hardening, hydrogen generation, photovoltaics, etc., in both space and terrestrial segment utilization. Additionally, at the high end of the concentration capability range, i.e., 60,000+, a solar-pulsed laser system is possible.

Synchronised laser chaos communication: statistical investigation of an experimental system

OpenAIRE

Lawrance, Anthony J.; Papamarkou, Theodore; Uchida, Atsushi

2017-01-01

The paper is concerned with analyzing data from an experimental antipodal laser-based chaos shift-keying communication system. Binary messages are embedded in a chaotically behaving laser wave which is transmitted through a fiber-optic cable and are decoded at the receiver using a second laser synchronized with the emitter laser. Instrumentation in the experimental system makes it particularly interesting to be able to empirically analyze both optical noise and synchronization error as well a...

Value-centric design architecture based on analysis of space system characteristics

Science.gov (United States)

Xu, Q.; Hollingsworth, P.; Smith, K.

2018-03-01

Emerging design concepts such as miniaturisation, modularity, and standardisation, have contributed to the rapid development of small and inexpensive platforms, particularly cubesats. This has been stimulating an upcoming revolution in space design and development, leading satellites into the era of "smaller, faster, and cheaper". However, the current requirement-centric design philosophy, focused on bespoke monolithic systems, along with the associated development and production process does not inherently fit with the innovative modular, standardised, and mass-produced technologies. This paper presents a new categorisation, characterisation, and value-centric design architecture to address this need for both traditional and novel system designs. Based on the categorisation of system configurations, a characterisation of space systems, comprised of duplication, fractionation, and derivation, is proposed to capture the overall system configuration characteristics and promote potential hybrid designs. Complying with the definitions of the system characterisation, mathematical mapping relations between the system characterisation and the system properties are described to establish the mathematical foundation of the proposed value-centric design methodology. To illustrate the methodology, subsystem reliability relationships are therefore analysed to explore potential system configurations in the design space. The results of the applications of system characteristic analysis clearly show that the effects of different configuration characteristics on the system properties can be effectively analysed and evaluated, enabling the optimization of system configurations.

Web-based Weather Expert System (WES) for Space Shuttle Launch

Science.gov (United States)

Bardina, Jorge E.; Rajkumar, T.

2003-01-01

The Web-based Weather Expert System (WES) is a critical module of the Virtual Test Bed development to support 'go/no go' decisions for Space Shuttle operations in the Intelligent Launch and Range Operations program of NASA. The weather rules characterize certain aspects of the environment related to the launching or landing site, the time of the day or night, the pad or runway conditions, the mission durations, the runway equipment and landing type. Expert system rules are derived from weather contingency rules, which were developed over years by NASA. Backward chaining, a goal-directed inference method is adopted, because a particular consequence or goal clause is evaluated first, and then chained backward through the rules. Once a rule is satisfied or true, then that particular rule is fired and the decision is expressed. The expert system is continuously verifying the rules against the past one-hour weather conditions and the decisions are made. The normal procedure of operations requires a formal pre-launch weather briefing held on Launch minus 1 day, which is a specific weather briefing for all areas of Space Shuttle launch operations. In this paper, the Web-based Weather Expert System of the Intelligent Launch and range Operations program is presented.

Research on propane leak detection system and device based on mid infrared laser

Science.gov (United States)

Jiang, Meng; Wang, Xuefeng; Wang, Junlong; Wang, Yizhao; Li, Pan; Feng, Qiaoling

2017-10-01

Propane is a key component of liquefied petroleum gas (LPG) and crude oil volatile. This issue summarizes the recent progress of propane detection technology. Meanwhile, base on the development trend, our latest progress is also provided. We demonstrated a mid infrared propane sensor system, which is based on wavelength modulation spectroscopy (WMS) technique with a CW interband cascade laser (ICL) emitting at 3370.4nm. The ICL laser scanned over a sharp feature in the broader spectrum of propane, and harmonic signals are obtained by lock-in amplifier for gas concentration deduction. The surrounding gas is extracted into the fine optical absorption cell through the pump to realize online detection. The absorption cell is designed in mid infrared windows range. An example experimental setup is shown. The second harmonic signals 2f and first harmonic signals1f are obtained. We present the sensor performance test data including dynamic precision and temperature stability. The propane detection sensor system and device is portable can carried on the mobile inspection vehicle platforms or intelligent robot inspection platform to realize the leakage monitoring of whole oil gas tank area.

Quantum cascade lasers as metrological tools for space optics

Science.gov (United States)

Bartalini, S.; Borri, S.; Galli, I.; Mazzotti, D.; Cancio Pastor, P.; Giusfredi, G.; De Natale, P.

2017-11-01

A distributed-feedback quantum-cascade laser working in the 4.3÷4.4 mm range has been frequency stabilized to the Lamb-dip center of a CO2 ro-vibrational transition by means of first-derivative locking to the saturated absorption signal, and its absolute frequency counted with a kHz-level precision and an overall uncertainty of 75 kHz. This has been made possible by an optical link between the QCL and a near-IR Optical Frequency Comb Synthesizer, thanks to a non-linear sum-frequency generation process with a fiber-amplified Nd:YAG laser. The implementation of a new spectroscopic technique, known as polarization spectroscopy, provides an improved signal for the locking loop, and will lead to a narrower laser emission and a drastic improvement in the frequency stability, that in principle is limited only by the stability of the optical frequency comb synthesizer (few parts in 1013). These results confirm quantum cascade lasers as reliable sources not only for high-sensitivity, but also for highprecision measurements, ranking them as optimal laser sources for space applications.

Demonstration of Laser Cutting System for Tube Specimen

Energy Technology Data Exchange (ETDEWEB)

Jin, Y. G.; Kim, G. S.; Heo, G. S.; Baik, S. J.; Kim, H. M.; Ahn, S. B. [KAERI, Daejeon (Korea, Republic of)

2016-05-15

The oxide layer removal system was also developed because the oxide layer on the surface of the irradiated fuel cladding and components interrupted the applying the electric current during the processing. However, it was found that the mechanical testing data of the irradiated specimens with removal of oxide layer was less reliable than the specimens with oxide layer . The laser cutting system using Nd:YAG with fiber optic beam delivery has great potential in material processing applications of the irradiated fuel cladding and components due to non-contact process. Thus, the oxide layer doesn't interrupt the fabrication process during the laser cutting system. In the present study, the laser cutting system was designed to fabricate the mechanical testing specimens from the unirradiated fuel cladding with and without oxide. The feasibility of the laser cutting system was demonstrated for the fabrication of various types of unirradiated specimens. The effect of surface oxide layer was also investigated for machining process of the zirlo fuel cladding and it was found that laser beam machining could be a useful tool to fabricate the specimens with surface oxide layer. Based on the feasibility studies and demonstration, the design of the laser cutting machine for fully or partially automatic and remotely operable system will be proposed and made.

Method of high precision interval measurement in pulse laser ranging system

Science.gov (United States)

Wang, Zhen; Lv, Xin-yuan; Mao, Jin-jin; Liu, Wei; Yang, Dong

2013-09-01

Laser ranging is suitable for laser system, for it has the advantage of high measuring precision, fast measuring speed,no cooperative targets and strong resistance to electromagnetic interference,the measuremen of laser ranging is the key paremeters affecting the performance of the whole system.The precision of the pulsed laser ranging system was decided by the precision of the time interval measurement, the principle structure of laser ranging system was introduced, and a method of high precision time interval measurement in pulse laser ranging system was established in this paper.Based on the analysis of the factors which affected the precision of range measure,the pulse rising edges discriminator was adopted to produce timing mark for the start-stop time discrimination,and the TDC-GP2 high precision interval measurement system based on TMS320F2812 DSP was designed to improve the measurement precision.Experimental results indicate that the time interval measurement method in this paper can obtain higher range accuracy. Compared with the traditional time interval measurement system,the method simplifies the system design and reduce the influence of bad weather conditions,furthermore,it satisfies the requirements of low costs and miniaturization.

A Simulation Base Investigation of High Latency Space Systems Operations

Science.gov (United States)

Li, Zu Qun; Crues, Edwin Z.; Bielski, Paul; Moore, Michael

2017-01-01

NASA's human space program has developed considerable experience with near Earth space operations. Although NASA has experience with deep space robotic missions, NASA has little substantive experience with human deep space operations. Even in the Apollo program, the missions lasted only a few weeks and the communication latencies were on the order of seconds. Human missions beyond the relatively close confines of the Earth-Moon system will involve missions with durations measured in months and communications latencies measured in minutes. To minimize crew risk and to maximize mission success, NASA needs to develop a better understanding of the implications of these types of mission durations and communication latencies on vehicle design, mission design and flight controller interaction with the crew. To begin to address these needs, NASA performed a study using a physics-based subsystem simulation to investigate the interactions between spacecraft crew and a ground-based mission control center for vehicle subsystem operations across long communication delays. The simulation, built with a subsystem modeling tool developed at NASA's Johnson Space Center, models the life support system of a Mars transit vehicle. The simulation contains models of the cabin atmosphere and pressure control system, electrical power system, drinking and waste water systems, internal and external thermal control systems, and crew metabolic functions. The simulation has three interfaces: 1) a real-time crew interface that can be use to monitor and control the vehicle subsystems; 2) a mission control center interface with data transport delays up to 15 minutes each way; 3) a real-time simulation test conductor interface that can be use to insert subsystem malfunctions and observe the interactions between the crew, ground, and simulated vehicle. The study was conducted at the 21st NASA Extreme Environment Mission Operations (NEEMO) mission between July 18th and Aug 3rd of year 2016. The NEEMO

Full-Duplex Digital Communication on a Single Laser Beam

Science.gov (United States)

Hazzard, D. A.; MacCannell, J. A.; Lee, G.; Selves, E. R.; Moore, D.; Payne, J. A.; Garrett, C. D.; Dahlstrom, N.; Shay, T. M.

2006-01-01

A proposed free-space optical communication system would operate in a full-duplex mode, using a single constant-power laser beam for transmission and reception of binary signals at both ends of the free-space optical path. The system was conceived for two-way data communication between a ground station and a spacecraft in a low orbit around the Earth. It has been estimated that in this application, a data rate of 10 kb/s could be achieved at a ground-station-to-spacecraft distance of 320 km, using a laser power of only 100 mW. The basic system concept is also applicable to terrestrial free-space optical communications. The system (see figure) would include a diode laser at one end of the link (originally, the ground station) and a liquid-crystal- based retroreflecting modulator at the other end of the link (originally, the spacecraft). At the laser end, the beam to be transmitted would be made to pass through a quarter-wave plate, which would convert its linear polarization to right circular polarization. For transmission of data from the laser end to the retroreflector end, the laser beam would be modulated with subcarrier phase-shift keying (SC-PSK). The transmitted beam would then pass through an aperture- sharing element (ASE) - basically, a mirror with a hole in it, used to separate the paths of the transmitted and received light beams. The transmitted beam would continue outward through a telescope (which, in the original application, would be equipped with a spacecraft-tracking system) that would launch the transmitted beam along the free-space optical path to the retroreflector end.

Laser based stripping system for measurement of the transverse emittance of H-beams at the CERN Linac4

CERN Document Server

Hofmann, T; Raich, U; Roncarolo, F; Cheymol, B

2013-01-01

The new LINAC4 at CERN will accelerate H- particles to 160 MeV and allow high brightness proton beam transfers to the Proton Synchrotron Booster, via a charge-exchange injection scheme. This paper describes the conceptual design of a laser system proposed for transverse profile and emittance measurements based on photon detachment of electrons from the H- ions. The binding energy of the outer electron is only 0.75 eV and can easily be stripped with a laser beam. Measuring the electron signal as function of the laser position allows the transverse beam profile to be reconstructed. A downstream dipole can also be used to separate the laser neutralized H0 atoms from the main H- beam. By imaging these H0 atoms as a function of laser position the transverse emittance can be reconstructed in the same way as in traditional slit-and-grid systems. By properly dimensioning the laser power and spot size, this method results in negligible beam losses and is therefore non-destructive. In addition, the absence of material ...

Safeguard Application Options for the Laser-Based Item Monitoring System (LBIMS)

International Nuclear Information System (INIS)

Laughter, Mark D

2008-01-01

Researchers at Oak Ridge National Laboratory (ORNL) are developing a Laser-Based Item Monitoring System (LBIMS) for advanced safeguards at nuclear facilities. LBIMS uses a low-power laser transceiver to monitor the presence and position of items with retroreflective tags. The primary advantages of LBIMS are its scalability to continuously monitor a wide range of items, its ability to operate unattended, its low cost of implementation, and its inherent information security due to its line-of-sight and non-broadcasting operation. The primary proposed safeguard application of LBIMS is described in its name: item monitoring. LBIMS could be implemented in a storage area to continuously monitor containers of nuclear material and the area in which they are stored. The system could be configured to provide off-site notification if any of the containers are moved or removed or if the area is accessed. Individual tags would be used to monitor storage containers, and additional tags could be used to record information regarding secondary storage units and room access. The capability to register small changes in tag position opens up the possibility of several other uses. These include continuously monitoring piping arrangements for design information verification or recording equipment positions for other safeguards systems, such as tracking the opening and closing of autoclaves as part of a cylinder tracking system or opening and closing valves on a sample or product take-off line. Combined with attribute tags, which transmit information from any kind of sensor by modulating the laser signal, LBIMS provides the capability to wirelessly and securely collect safeguards data, even in areas where radio-frequency or other wireless communication methods are not practicable. Four application types are described in this report: static item monitoring, in-process item monitoring with trigger tags, multi-layered integration with trigger tags, and line-of-sight data transfer with

Transmission media appropriate laser-microwave solar power satellite system

Science.gov (United States)

Schäfer, C. A.; Gray, D.

2012-10-01

As a solution to the most critical problems with Solar power Satellite (SPS) development, a system is proposed which uses laser power transmission in space to a receiver high in the atmosphere that relays the power to Earth by either cable or microwave power transmission. It has been shown in the past that such hybrid systems have the advantages of a reduction in the mass of equipment required in geostationary orbit and avoidance of radio frequency interference with other satellites and terrestrial communications systems. The advantage over a purely laser power beam SPS is that atmospheric absorption is avoided and outages due to clouds and precipitation will not occur, allowing for deployment in the equatorial zone and guaranteeing year round operation. This proposal is supported by brief literature surveys and theoretical calculations to estimate crucial parameters in this paper. In relation to this concept, we build on a recently proposed method to collect solar energy by a tethered balloon at high altitude because it enables a low-cost start for bringing the first Watt of power to Earth giving some quick return on investment, which is desperately missing in the traditional SPS concept. To tackle the significant problem of GW-class SPSs of high launch cost per kg mass brought to space, this paper introduces a concept which aims to achieve a superior power over mass ratio compared to traditional satellite designs by the use of thin-film solar cells combined with optical fibres for power delivery. To minimise the aperture sizes and cost of the transmitting and receiving components of the satellite and high altitude receiver, closed-loop laser beam pointing and target tracking is crucial for pointing a laser beam onto a target area that is of similar size to the beam's diameter. A recently developed technique based on optical phase conjugation is introduced and its applicability for maintaining power transmission between the satellite and high altitude receiver is

A novel weld seam detection method for space weld seam of narrow butt joint in laser welding

Science.gov (United States)

Shao, Wen Jun; Huang, Yu; Zhang, Yong

2018-02-01

Structured light measurement is widely used for weld seam detection owing to its high measurement precision and robust. However, there is nearly no geometrical deformation of the stripe projected onto weld face, whose seam width is less than 0.1 mm and without misalignment. So, it's very difficult to ensure an exact retrieval of the seam feature. This issue is raised as laser welding for butt joint of thin metal plate is widely applied. Moreover, measurement for the seam width, seam center and the normal vector of the weld face at the same time during welding process is of great importance to the welding quality but rarely reported. Consequently, a seam measurement method based on vision sensor for space weld seam of narrow butt joint is proposed in this article. Three laser stripes with different wave length are project on the weldment, in which two red laser stripes are designed and used to measure the three dimensional profile of the weld face by the principle of optical triangulation, and the third green laser stripe is used as light source to measure the edge and the centerline of the seam by the principle of passive vision sensor. The corresponding image process algorithm is proposed to extract the centerline of the red laser stripes as well as the seam feature. All these three laser stripes are captured and processed in a single image so that the three dimensional position of the space weld seam can be obtained simultaneously. Finally, the result of experiment reveals that the proposed method can meet the precision demand of space narrow butt joint.

Laser systems for on-line laser ion sources

International Nuclear Information System (INIS)

Geppert, Christopher

2008-01-01

Since its initiation in the middle of the 1980s, the resonant ionization laser ion source has been established as a reliable and efficient on-line ion source for radioactive ion beams. In comparison to other on-line ion sources it comprises the advantages of high versatility for the elements to be ionized and of high selectivity and purity for the ion beam generated by resonant laser radiation. Dye laser systems have been the predominant and pioneering working horses for laser ion source applications up to recently, but the development of all-solid-state titanium:sapphire laser systems has nowadays initiated a significant evolution within this field. In this paper an overview of the ongoing developments will be given, which have contributed to the establishment of a number of new laser ion source facilities worldwide during the last five years.

Navigated Pattern Laser System versus Single-Spot Laser System for Postoperative 360-Degree Laser Retinopexy.

Science.gov (United States)

Kulikov, Alexei N; Maltsev, Dmitrii S; Boiko, Ernest V

2016-01-01

Purpose . To compare three 360°-laser retinopexy (LRP) approaches (using navigated pattern laser system, single-spot slit-lamp (SL) laser delivery, and single-spot indirect ophthalmoscope (IO) laser delivery) in regard to procedure duration, procedural pain score, technical difficulties, and the ability to achieve surgical goals. Material and Methods . Eighty-six rhegmatogenous retinal detachment patients (86 eyes) were included in this prospective randomized study. The mean procedural time, procedural pain score (using 4-point Verbal Rating Scale), number of laser burns, and achievement of the surgical goals were compared between three groups (pattern LRP (Navilas® laser system), 36 patients; SL-LRP, 28 patients; and IO-LRP, 22 patients). Results . In the pattern LRP group, the amount of time needed for LRP and pain level were statistically significantly lower, whereas the number of applied laser burns was higher compared to those in the SL-LRP group and in the IO-LRP group. In the pattern LRP, SL-LRP, and IO-LRP groups, surgical goals were fully achieved in 28 (77.8%), 17 (60.7%), and 13 patients (59.1%), respectively ( p > 0.05). Conclusion . The navigated pattern approach allows improving the treatment time and pain in postoperative 360° LRP. Moreover, 360° pattern LRP is at least as effective in achieving the surgical goal as the conventional (slit-lamp or indirect ophthalmoscope) approaches with a single-spot laser.

Laser Ranging in Solar System: Technology Developments and New Science Measurement Capabilities

Science.gov (United States)

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

2015-12-01

Laser Ranging has played a major role in geodetic studies of the Earth over the past 40 years. The technique can potentially be used in between planets and spacecrafts within the solar system to advance planetary science. For example, a direct measurement of distances between planets, such as Mars and Venus would make significant improvements in understanding the dynamics of the whole solar system, including the masses of the planets and moons, asteroids and their perturbing interactions, and the gravity field of the Sun. Compared to the conventional radio frequency (RF) tracking systems, laser ranging is potentially more accurate because it is much less sensitive to the transmission media. It is also more efficient because the laser beams are much better focused onto the targets than RF beams. However, existing laser ranging systems are all Earth centric, that is, from ground stations on Earth to orbiting satellites in near Earth orbits or lunar orbit, and to the lunar retro-reflector arrays deployed by the astronauts in the early days of lunar explorations. Several long distance laser ranging experiments have been conducted with the lidar in space, including a two-way laser ranging demonstration between Earth and the Mercury Laser Altimeter (MLA) on the MESSENGER spacecraft over 24 million km, and a one way laser transmission and detection experiment over 80 million km between Earth and the Mars Orbiting Laser Altimeter (MOLA) on the MGS spacecraft in Mars orbit. A one-way laser ranging operation has been carried out continuously from 2009 to 2014 between multiple ground stations to LRO spacecraft in lunar orbit. The Lunar Laser Communication Demonstration (LLCD) on the LADEE mission has demonstrated that a two way laser ranging measurements, including both the Doppler frequency and the phase shift, can be obtained from the subcarrier or the data clocks of a high speed duplex laser communication system. Plans and concepts presently being studied suggest we may be

Research on Measurement Accuracy of Laser Tracking System Based on Spherical Mirror with Rotation Errors of Gimbal Mount Axes

Science.gov (United States)

Shi, Zhaoyao; Song, Huixu; Chen, Hongfang; Sun, Yanqiang

2018-02-01

This paper presents a novel experimental approach for confirming that spherical mirror of a laser tracking system can reduce the influences of rotation errors of gimbal mount axes on the measurement accuracy. By simplifying the optical system model of laser tracking system based on spherical mirror, we can easily extract the laser ranging measurement error caused by rotation errors of gimbal mount axes with the positions of spherical mirror, biconvex lens, cat's eye reflector, and measuring beam. The motions of polarization beam splitter and biconvex lens along the optical axis and vertical direction of optical axis are driven by error motions of gimbal mount axes. In order to simplify the experimental process, the motion of biconvex lens is substituted by the motion of spherical mirror according to the principle of relative motion. The laser ranging measurement error caused by the rotation errors of gimbal mount axes could be recorded in the readings of laser interferometer. The experimental results showed that the laser ranging measurement error caused by rotation errors was less than 0.1 μm if radial error motion and axial error motion were within ±10 μm. The experimental method simplified the experimental procedure and the spherical mirror could reduce the influences of rotation errors of gimbal mount axes on the measurement accuracy of the laser tracking system.

Temporal characteristic analysis of laser-modulated pulsed X-ray source for space X-ray communication

Science.gov (United States)

Hang, Shuang; Liu, Yunpeng; Li, Huan; Tang, Xiaobin; Chen, Da

2018-04-01

X-ray communication (XCOM) is a new communication type and is expected to realize high-speed data transmission in some special communication scenarios, such as deep space communication and blackout communication. This study proposes a high-speed modulated X-ray source scheme based on the laser-to-X-ray conversion. The temporal characteristics of the essential components of the proposed laser-modulated pulsed X-ray source (LMPXS) were analyzed to evaluate its pulse emission performance. Results show that the LMPXS can provide a maximum modulation rate up to 100 Mbps which is expected to significantly improve the data rate of XCOM.

Rf and space-charge induced emittances in laser-driven rf guns

International Nuclear Information System (INIS)

Kim, Kwang-Je; Chen, Yu-Jiuan.

1988-10-01

Laser-driven rf electron guns are potential sources of high-current, low-emittance, short bunch-length electron beams, which are required for many advanced accelerator applications, such as free-electron lasers and injectors for high-energy machines. In such guns the design of which was pioneered at Los Alamos National Laboratory and which is currently being developed at several other laboratories, a high-power laser beam illuminates a photo-cathode surface placed on an end wall of an rf cavity. The main advantages of this type of gun are that the time structure of the electron beam is controlled by the laser, eliminating the need for bunchers, and that the electric field in rf cavities can be made very strong, so that the effects due to space-charge repulsion can be minimized. In this paper, we present an approximate but simple analysis for the transverse and longitudinal emittances in rf guns that takes into account both the time variation of the rf field and the space-charge effect. The results are compared and found to agree well with those from simulation. 7 refs., 6 figs

Development and application of an automatic system for measuring the laser camera

International Nuclear Information System (INIS)

Feng Shuli; Peng Mingchen; Li Kuncheng

2004-01-01

Objective: To provide an automatic system for measuring imaging quality of laser camera, and to make an automatic measurement and analysis system. Methods: On the special imaging workstation (SGI 540), the procedure was written by using Matlab language. An automatic measurement and analysis system of imaging quality for laser camera was developed and made according to the imaging quality measurement standard of laser camera of International Engineer Commission (IEC). The measurement system used the theories of digital signal processing, and was based on the characteristics of digital images, as well as put the automatic measurement and analysis of laser camera into practice by the affiliated sample pictures of the laser camera. Results: All the parameters of imaging quality of laser camera, including H-D and MTF curve, low and middle and high resolution of optical density, all kinds of geometry distort, maximum and minimum density, as well as the dynamic range of gray scale, could be measured by this system. The system was applied for measuring the laser cameras in 20 hospitals in Beijing. The measuring results showed that the system could provide objective and quantitative data, and could accurately evaluate the imaging quality of laser camera, as well as correct the results made by manual measurement based on the affiliated sample pictures of the laser camera. Conclusion: The automatic measuring system of laser camera is an effective and objective tool for testing the quality of the laser camera, and the system makes a foundation for the future research

A Framework Based on Reference Data with Superordinate Accuracy for the Quality Analysis of Terrestrial Laser Scanning-Based Multi-Sensor-Systems.

Science.gov (United States)

Stenz, Ulrich; Hartmann, Jens; Paffenholz, Jens-André; Neumann, Ingo

2017-08-16

Terrestrial laser scanning (TLS) is an efficient solution to collect large-scale data. The efficiency can be increased by combining TLS with additional sensors in a TLS-based multi-sensor-system (MSS). The uncertainty of scanned points is not homogenous and depends on many different influencing factors. These include the sensor properties, referencing, scan geometry (e.g., distance and angle of incidence), environmental conditions (e.g., atmospheric conditions) and the scanned object (e.g., material, color and reflectance, etc.). The paper presents methods, infrastructure and results for the validation of the suitability of TLS and TLS-based MSS. Main aspects are the backward modelling of the uncertainty on the basis of reference data (e.g., point clouds) with superordinate accuracy and the appropriation of a suitable environment/infrastructure (e.g., the calibration process of the targets for the registration of laser scanner and laser tracker data in a common coordinate system with high accuracy) In this context superordinate accuracy means that the accuracy of the acquired reference data is better by a factor of 10 than the data of the validated TLS and TLS-based MSS. These aspects play an important role in engineering geodesy, where the aimed accuracy lies in a range of a few mm or less.

Laser system for testing radiation imaging detector circuits

Science.gov (United States)

Zubrzycka, Weronika; Kasinski, Krzysztof

2015-09-01

Performance and functionality of radiation imaging detector circuits in charge and position measurement systems need to meet tight requirements. It is therefore necessary to thoroughly test sensors as well as read-out electronics. The major disadvantages of using radioactive sources or particle beams for testing are high financial expenses and limited accessibility. As an alternative short pulses of well-focused laser beam are often used for preliminary tests. There are number of laser-based devices available on the market, but very often their applicability in this field is limited. This paper describes concept, design and validation of laser system for testing silicon sensor based radiation imaging detector circuits. The emphasis is put on keeping overall costs low while achieving all required goals: mobility, flexible parameters, remote control and possibility of carrying out automated tests. The main part of the developed device is an optical pick-up unit (OPU) used in optical disc drives. The hardware includes FPGA-controlled circuits for laser positioning in 2 dimensions (horizontal and vertical), precision timing (frequency and number) and amplitude (diode current) of short ns-scale (3.2 ns) light pulses. The system is controlled via USB interface by a dedicated LabVIEW-based application enabling full manual or semi-automated test procedures.

Mid-IR laser system for advanced neurosurgery

Science.gov (United States)

Klosner, M.; Wu, C.; Heller, D. F.

2014-03-01

We present work on a laser system operating in the near- and mid-IR spectral regions, having output characteristics designed to be optimal for cutting various tissue types. We provide a brief overview of laser-tissue interactions and the importance of controlling certain properties of the light beam. We describe the principle of operation of the laser system, which is generally based on a wavelength-tunable alexandrite laser oscillator/amplifier, and multiple Raman conversion stages. This configuration provides robust access to the mid-IR spectral region at wavelengths, pulse energies, pulse durations, and repetition rates that are attractive for neurosurgical applications. We summarize results for ultra-precise selective cutting of nerve sheaths and retinas with little collateral damage; this has applications in procedures such as optic-nerve-sheath fenestration and possible spinal repair. We also report results for cutting cornea, and dermal tissues.

Model-based system-of-systems engineering for space-based command, control, communication, and information architecture design

Science.gov (United States)

Sindiy, Oleg V.

This dissertation presents a model-based system-of-systems engineering (SoSE) approach as a design philosophy for architecting in system-of-systems (SoS) problems. SoS refers to a special class of systems in which numerous systems with operational and managerial independence interact to generate new capabilities that satisfy societal needs. Design decisions are more complicated in a SoS setting. A revised Process Model for SoSE is presented to support three phases in SoS architecting: defining the scope of the design problem, abstracting key descriptors and their interrelations in a conceptual model, and implementing computer-based simulations for architectural analyses. The Process Model enables improved decision support considering multiple SoS features and develops computational models capable of highlighting configurations of organizational, policy, financial, operational, and/or technical features. Further, processes for verification and validation of SoS models and simulations are also important due to potential impact on critical decision-making and, thus, are addressed. Two research questions frame the research efforts described in this dissertation. The first concerns how the four key sources of SoS complexity---heterogeneity of systems, connectivity structure, multi-layer interactions, and the evolutionary nature---influence the formulation of SoS models and simulations, trade space, and solution performance and structure evaluation metrics. The second question pertains to the implementation of SoSE architecting processes to inform decision-making for a subset of SoS problems concerning the design of information exchange services in space-based operations domain. These questions motivate and guide the dissertation's contributions. A formal methodology for drawing relationships within a multi-dimensional trade space, forming simulation case studies from applications of candidate architecture solutions to a campaign of notional mission use cases, and

Laser Materials Processing for NASA's Aerospace Structural Materials

Science.gov (United States)

Nagarathnam, Karthik; Hunyady, Thomas A.

2001-01-01

Lasers are useful for performing operations such as joining, machining, built-up freeform fabrication, and surface treatment. Due to the multifunctional nature of a single tool and the variety of materials that can be processed, these attributes are attractive in order to support long-term missions in space. However, current laser technology also has drawbacks for space-based applications. Specifically, size, power efficiency, lack of robustness, and problems processing highly reflective materials are all concerns. With the advent of recent breakthroughs in solidstate laser (e.g., diode-pumped lasers) and fiber optic technologies, the potential to perform multiple processing techniques in space has increased significantly. A review of the historical development of lasers from their infancy to the present will be used to show how these issues may be addressed. The review will also indicate where further development is necessary to realize a laser-based materials processing capability in space. The broad utility of laser beams in synthesizing various classes of engineering materials will be illustrated using state-of-the art processing maps for select lightweight alloys typically found on spacecraft. Both short- and long-term space missions will benefit from the development of a universal laser-based tool with low power consumption, improved process flexibility, compactness (e.g., miniaturization), robustness, and automation for maximum utility with a minimum of human interaction. The potential advantages of using lasers with suitable wavelength and beam properties for future space missions to the moon, Mars and beyond will be discussed. The laser processing experiments in the present report were performed using a diode pumped, pulsed/continuous wave Nd:YAG laser (50 W max average laser power), with a 1064 nm wavelength. The processed materials included Ti-6AI-4V, Al-2219 and Al-2090. For Phase I of this project, the laser process conditions were varied and optimized

Computer graphics testbed to simulate and test vision systems for space applications

Science.gov (United States)

Cheatham, John B.

1991-01-01

Artificial intelligence concepts are applied to robotics. Artificial neural networks, expert systems and laser imaging techniques for autonomous space robots are being studied. A computer graphics laser range finder simulator developed by Wu has been used by Weiland and Norwood to study use of artificial neural networks for path planning and obstacle avoidance. Interest is expressed in applications of CLIPS, NETS, and Fuzzy Control. These applications are applied to robot navigation.

Higher order sliding mode control of laser pointing for orbital debris mitigation

Science.gov (United States)

Palosz, Arthur

This thesis explores the use of a space-based laser to clean up small orbital debris from near Earth space. This system's challenge is to quickly and precisely aim the laser beam at very small (laser beam onto the orbital debris. A Kalman Filter (KF) is designed to accurately track the orbital debris and generate a command signal for the controller. A second order Super Twisting Sliding Mode Controller (2-SMC) is designed to follow the command signal generated by the KF and to overcome the parametric uncertainties and external disturbances. The performance of the system is validated with a computer simulation created in MATLAB and Simulink.

Effective Data-Driven Calibration for a Galvanometric Laser Scanning System Using Binocular Stereo Vision.

Science.gov (United States)

Tu, Junchao; Zhang, Liyan

2018-01-12

A new solution to the problem of galvanometric laser scanning (GLS) system calibration is presented. Under the machine learning framework, we build a single-hidden layer feedforward neural network (SLFN）to represent the GLS system, which takes the digital control signal at the drives of the GLS system as input and the space vector of the corresponding outgoing laser beam as output. The training data set is obtained with the aid of a moving mechanism and a binocular stereo system. The parameters of the SLFN are efficiently solved in a closed form by using extreme learning machine (ELM). By quantitatively analyzing the regression precision with respective to the number of hidden neurons in the SLFN, we demonstrate that the proper number of hidden neurons can be safely chosen from a broad interval to guarantee good generalization performance. Compared to the traditional model-driven calibration, the proposed calibration method does not need a complex modeling process and is more accurate and stable. As the output of the network is the space vectors of the outgoing laser beams, it costs much less training time and can provide a uniform solution to both laser projection and 3D-reconstruction, in contrast with the existing data-driven calibration method which only works for the laser triangulation problem. Calibration experiment, projection experiment and 3D reconstruction experiment are respectively conducted to test the proposed method, and good results are obtained.

Effective Data-Driven Calibration for a Galvanometric Laser Scanning System Using Binocular Stereo Vision

Directory of Open Access Journals (Sweden)

Junchao Tu

2018-01-01

Full Text Available A new solution to the problem of galvanometric laser scanning (GLS system calibration is presented. Under the machine learning framework, we build a single-hidden layer feedforward neural network (SLFN）to represent the GLS system, which takes the digital control signal at the drives of the GLS system as input and the space vector of the corresponding outgoing laser beam as output. The training data set is obtained with the aid of a moving mechanism and a binocular stereo system. The parameters of the SLFN are efficiently solved in a closed form by using extreme learning machine (ELM. By quantitatively analyzing the regression precision with respective to the number of hidden neurons in the SLFN, we demonstrate that the proper number of hidden neurons can be safely chosen from a broad interval to guarantee good generalization performance. Compared to the traditional model-driven calibration, the proposed calibration method does not need a complex modeling process and is more accurate and stable. As the output of the network is the space vectors of the outgoing laser beams, it costs much less training time and can provide a uniform solution to both laser projection and 3D-reconstruction, in contrast with the existing data-driven calibration method which only works for the laser triangulation problem. Calibration experiment, projection experiment and 3D reconstruction experiment are respectively conducted to test the proposed method, and good results are obtained.

Laser-Based Surface Modification of Microstructure for Carbon Fiber-Reinforced Plastics

Science.gov (United States)

Yang, Wenfeng; Sun, Ting; Cao, Yu; Li, Shaolong; Liu, Chang; Tang, Qingru

2018-05-01

Bonding repair is a powerful feature of carbon fiber-reinforced plastics (CFRP). Based on the theory of interface bonding, the interface adhesion strength and reliability of the CFRP structure will be directly affected by the microscopic features of the CFRP surface, including the microstructure, physical, and chemical characteristics. In this paper, laser-based surface modification was compared to Peel-ply, grinding, and polishing to comparatively evaluate the surface microstructure of CFRP. The surface microstructure, morphology, fiber damage, height and space parameters were investigated by scanning electron microscopy (SEM) and laser confocal microscopy (LCM). Relative to the conventional grinding process, laser modification of the CFRP surface can result in more uniform resin removal and better processing control and repeatability. This decreases the adverse impact of surface fiber fractures and secondary damage. The surface properties were significantly optimized, which has been reflected such things as the obvious improvement of surface roughness, microstructure uniformity, and actual area. The improved surface microstructure based on laser modification is more conducive to interface bonding of CFRP structure repair. This can enhance the interfacial adhesion strength and reliability of repair.

Research on laser detonation pulse circuit with low-power based on super capacitor

Science.gov (United States)

Wang, Hao-yu; Hong, Jin; He, Aifeng; Jing, Bo; Cao, Chun-qiang; Ma, Yue; Chu, En-yi; Hu, Ya-dong

2018-03-01

According to the demand of laser initiating device miniaturization and low power consumption of weapon system, research on the low power pulse laser detonation circuit with super capacitor. Established a dynamic model of laser output based on super capacitance storage capacity, discharge voltage and programmable output pulse width. The output performance of the super capacitor under different energy storage capacity and discharge voltage is obtained by simulation. The experimental test system was set up, and the laser diode of low power pulsed laser detonation circuit was tested and the laser output waveform of laser diode in different energy storage capacity and discharge voltage was collected. Experiments show that low power pulse laser detonation based on super capacitor energy storage circuit discharge with high efficiency, good transient performance, for a low power consumption requirement, for laser detonation system and low power consumption and provide reference light miniaturization of engineering practice.

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

Reachable Distance Space: Efficient Sampling-Based Planning for Spatially Constrained Systems

KAUST Repository

Xinyu Tang,

2010-01-25

Motion planning for spatially constrained robots is difficult due to additional constraints placed on the robot, such as closure constraints for closed chains or requirements on end-effector placement for articulated linkages. It is usually computationally too expensive to apply sampling-based planners to these problems since it is difficult to generate valid configurations. We overcome this challenge by redefining the robot\\'s degrees of freedom and constraints into a new set of parameters, called reachable distance space (RD-space), in which all configurations lie in the set of constraint-satisfying subspaces. This enables us to directly sample the constrained subspaces with complexity linear in the number of the robot\\'s degrees of freedom. In addition to supporting efficient sampling of configurations, we show that the RD-space formulation naturally supports planning and, in particular, we design a local planner suitable for use by sampling-based planners. We demonstrate the effectiveness and efficiency of our approach for several systems including closed chain planning with multiple loops, restricted end-effector sampling, and on-line planning for drawing/sculpting. We can sample single-loop closed chain systems with 1,000 links in time comparable to open chain sampling, and we can generate samples for 1,000-link multi-loop systems of varying topologies in less than a second. © 2010 The Author(s).

Laser power beaming: an emerging technology for power transmission and propulsion in space

Science.gov (United States)

Bennett, Harold E.

1997-05-01

A ground based laser beam transmitted to space can be used as an electric utility for satellites. It can significantly increase the electric power available to operate a satellite or to transport it from low earth orbit (LEO) to mid earth or geosynchronous orbits. The increase in electrical power compared to that obtainable from the sun is as much as 1000% for the same size solar panels. An increase in satellite electric power is needed to meet the increasing demands for power caused by the advent of 'direct to home TV,' for increased telecommunications, or for other demands made by the burgeoning 'space highway.' Monetary savings as compared to putting up multiple satellites in the same 'slot' can be over half a billion dollars. To obtain propulsion, the laser power can be beamed through the atmosphere to an 'orbit transfer vehicle' (OTV) satellite which travels back and forth between LEO and higher earth orbits. The OTV will transport the satellite into orbit as does a rocket but does not require the heavy fuel load needed if rocket propulsion is used. Monetary savings of 300% or more in launch costs are predicted. Key elements in the proposed concept are a 100 to 200 kW free- electron laser operating at 0.84 m in the photographic infrared region of the spectrum and a novel adaptive optic telescope.

Space inhomogeneity and detuning effects in a laser with a saturable absorber: a first-order approximation

Energy Technology Data Exchange (ETDEWEB)

Garcia-Fernandez, P.; Velarde, M.G.

1988-05-01

To a first approximation the effects of detuning and/or space inhomogeneity on the stability domain of a model for a laser with a saturable absorber are presented. It appears that the space dependence increases the domain of the emissionless state, thus delaying the laser action.

Study and development of a laser based alignment system for the compact linear collider

CERN Document Server

AUTHOR|(CDS)2083149

The first objective of the PhD thesis is to develop a new type of positioning sensor to align components at micrometre level over 200 m with respect to a laser beam as straight line reference. The second objective is to estimate the measurement accuracy of the total alignment system over 200 m. The context of the PhD thesis is the Compact Linear Collider project, which is a study for a future particle accelerator. The proposed positioning sensor is made of a camera and an open/close shutter. The sensor can measure the position of the laser beam with respect to its own coordinate system. To do a measurement, the shutter closes, a laser spot appears on it, the camera captures a picture of the laser spot and the coordinates of the laser spot centre are reconstructed in the sensor coordinate system with image processing. Such a measurement requires reference targets on the positioning sensor. To reach the rst objective of the PhD thesis, we used laser theory...

1.9 W yellow, CW, high-brightness light from a high efficiency semiconductor laser-based system

Science.gov (United States)

Hansen, A. K.; Christensen, M.; Noordegraaf, D.; Heist, P.; Papastathopoulos, E.; Loyo-Maldonado, V.; Jensen, O. B.; Stock, M. L.; Skovgaard, P. M. W.

2017-02-01

Semiconductor lasers are ideal sources for efficient electrical-to-optical power conversion and for many applications where their small size and potential for low cost are required to meet market demands. Yellow lasers find use in a variety of bio-related applications, such as photocoagulation, imaging, flow cytometry, and cancer treatment. However, direct generation of yellow light from semiconductors with sufficient beam quality and power has so far eluded researchers. Meanwhile, tapered semiconductor lasers at near-infrared wavelengths have recently become able to provide neardiffraction- limited, single frequency operation with output powers up to 8 W near 1120 nm. We present a 1.9 W single frequency laser system at 562 nm, based on single pass cascaded frequency doubling of such a tapered laser diode. The laser diode is a monolithic device consisting of two sections: a ridge waveguide with a distributed Bragg reflector, and a tapered amplifier. Using single-pass cascaded frequency doubling in two periodically poled lithium niobate crystals, 1.93 W of diffraction-limited light at 562 nm is generated from 5.8 W continuous-wave infrared light. When turned on from cold, the laser system reaches full power in just 60 seconds. An advantage of using a single pass configuration, rather than an external cavity configuration, is increased stability towards external perturbations. For example, stability to fluctuating case temperature over a 30 K temperature span has been demonstrated. The combination of high stability, compactness and watt-level power range means this technology is of great interest for a wide range of biological and biomedical applications.

Space and energy. [space systems for energy generation, distribution and control

Science.gov (United States)

Bekey, I.

1976-01-01

Potential contributions of space to energy-related activities are discussed. Advanced concepts presented include worldwide energy distribution to substation-sized users using low-altitude space reflectors; powering large numbers of large aircraft worldwide using laser beams reflected from space mirror complexes; providing night illumination via sunlight-reflecting space mirrors; fine-scale power programming and monitoring in transmission networks by monitoring millions of network points from space; prevention of undetected hijacking of nuclear reactor fuels by space tracking of signals from tagging transmitters on all such materials; and disposal of nuclear power plant radioactive wastes in space.

Spatial beam shaping using a micro-structured optical fiber and all-fiber laser amplification system for large-scale laser facilities seeding

International Nuclear Information System (INIS)

Calvet, Pierre

2014-01-01

Spatial beam shaping is an important topic for the lasers applications. For various industrial areas (marking, drilling, laser-matter interaction, high-power laser seeding...) the optical beam has to be flattened. Currently, the state of the art of the beam shaping: 'free-space' solutions or highly multimode fibers, are not fully suitable. The first ones are very sensitive to any perturbations and the maintenance is challenging, the second ones cannot deliver a coherent beam. For this reason, we present in this manuscript a micro-structured optical single-mode fiber delivering a spatially flattened beam. This 'Top-Hat' fiber can shape any beam in a spatially coherent beam what is a progress with respect to the highly multimode fibers used in the state of the art. The optical fibers are easy to use and very robust, what is a strong benefit with respect to the 'free-space' solutions. Thanks to this fiber, we could realize an all-fiber multi-stage laser chain to amplify a 10 ns pulse to 100 μJ. Moreover the temporal, spectral and spatial properties were preserved. We adapted this 'Top-Hat' fiber to this multi-stage laser chain, we proved the capability and the interest of this fiber for the spatial beam shaping of the laser beams in highly performing and robust laser systems. (author) [fr

Architectural design of a ground-based deep-space optical reception antenna

Science.gov (United States)

Kerr, E. L.

1989-01-01

An architectural design of a ground-based antenna (telescope) for receiving optical communications from deep space is presented. Physical and optical parameters, and their effect on the performance and cost considerations, are described. The channel capacity of the antenna is 100 kbits/s from Saturn and 5 Mbits/s from Mars. A novel sunshade is designed to permit optical communication even when the deep-space laser source is as close to the sun as 12 deg. Inserts in the tubes of the sunshade permit operations at solar elongations as small as 6 or 3 deg. The Nd:YAG source laser and the Fraunhofer filter (a narrow-band predetection optical filter) are tuned to match the Doppler shifts of the source and background. A typical Saturn-to-earth data link can reduce its source power requirement from 8.2 W to 2 W of laser output by employing a Fraunhofer filter instead of a conventional multilayer dielectric filter.

Investigation into the Use of the Concept Laser QM System as an In-Situ Research and Evaluation Tool

Science.gov (United States)

Bagg, Stacey

2014-01-01

The NASA Marshall Space Flight Center (MSFC) is using a Concept Laser Fusing (Cusing) M2 powder bed additive manufacturing system for the build of space flight prototypes and hardware. NASA MSFC is collecting and analyzing data from the M2 QM Meltpool and QM Coating systems for builds. This data is intended to aide in understanding of the powder-bed additive manufacturing process, and in the development of a thermal model for the process. The QM systems are marketed by Concept Laser GmbH as in-situ quality management modules. The QM Meltpool system uses both a high-speed near-IR camera and a photodiode to monitor the melt pool generated by the laser. The software determines from the camera images the size of the melt pool. The camera also measures the integrated intensity of the IR radiation, and the photodiode gives an intensity value based on the brightness of the melt pool. The QM coating system uses a high resolution optical camera to image the surface after each layer has been formed. The objective of this investigation was to determine the adequacy of the QM Meltpool system as a research instrument for in-situ measurement of melt pool size and temperature and its applicability to NASA's objectives in (1) Developing a process thermal model and (2) Quantifying feedback measurements with the intent of meeting quality requirements or specifications. Note that Concept Laser markets the system only as capable of giving an indication of changes between builds, not as an in-situ research and evaluation tool. A secondary objective of the investigation is to determine the adequacy of the QM Coating system as an in-situ layer-wise geometry and layer quality evaluation tool.

Two Micron Laser Technology Advancements at NASA Langley Research Center

Science.gov (United States)

Singh, Upendra N.

2010-01-01

An Independent Laser Review Panel set up to examine NASA s space-based lidar missions and the technology readiness of lasers appropriate for space-based lidars indicated a critical need for an integrated research and development strategy to move laser transmitter technology from low technical readiness levels to the higher levels required for space missions. Based on the review, a multiyear Laser Risk Reduction Program (LRRP) was initiated by NASA in 2002 to develop technologies that ensure the successful development of the broad range of lidar missions envisioned by NASA. This presentation will provide an overview of the development of pulsed 2-micron solid-state laser technologies at NASA Langley Research Center for enabling space-based measurement of wind and carbon dioxide.

Development of automatic laser welding system

International Nuclear Information System (INIS)

Ohwaki, Katsura

2002-01-01

Laser are a new production tool for high speed and low distortion welding and applications to automatic welding lines are increasing. IHI has long experience of laser processing for the preservation of nuclear power plants, welding of airplane engines and so on. Moreover, YAG laser oscillators and various kinds of hardware have been developed for laser welding and automation. Combining these welding technologies and laser hardware technologies produce the automatic laser welding system. In this paper, the component technologies are described, including combined optics intended to improve welding stability, laser oscillators, monitoring system, seam tracking system and so on. (author)

A Ground-Based Validation System of Teleoperation for a Space Robot

Directory of Open Access Journals (Sweden)

Xueqian Wang

2012-10-01

Full Text Available Teleoperation of space robots is very important for future on-orbit service. In order to assure the task is accomplished successfully, ground experiments are required to verify the function and validity of the teleoperation system before a space robot is launched. In this paper, a ground-based validation subsystem is developed as a part of a teleoperation system. The subsystem is mainly composed of four parts: the input verification module, the onboard verification module, the dynamic and image workstation, and the communication simulator. The input verification module, consisting of hardware and software of the master, is used to verify the input ability. The onboard verification module, consisting of the same hardware and software as the onboard processor, is used to verify the processor's computing ability and execution schedule. In addition, the dynamic and image workstation calculates the dynamic response of the space robot and target, and generates emulated camera images, including the hand-eye cameras, global-vision camera and rendezvous camera. The communication simulator provides fidelity communication conditions, i.e., time delays and communication bandwidth. Lastly, we integrated a teleoperation system and conducted many experiments on the system. Experiment results show that the ground system is very useful for verified teleoperation technology.

Next generation laser-based standoff spectroscopy techniques for Mars exploration.

Science.gov (United States)

Gasda, Patrick J; Acosta-Maeda, Tayro E; Lucey, Paul G; Misra, Anupam K; Sharma, Shiv K; Taylor, G Jeffrey

2015-01-01

In the recent Mars 2020 Rover Science Definition Team Report, the National Aeronautics and Space Administration (NASA) has sought the capability to detect and identify elements, minerals, and most importantly, biosignatures, at fine scales for the preparation of a retrievable cache of samples. The current Mars rover, the Mars Science Laboratory Curiosity, has a remote laser-induced breakdown spectroscopy (LIBS) instrument, a type of quantitative elemental analysis, called the Chemistry Camera (ChemCam) that has shown that laser-induced spectroscopy instruments are not only feasible for space exploration, but are reliable and complementary to traditional elemental analysis instruments such as the Alpha Particle X-Ray Spectrometer. The superb track record of ChemCam has paved the way for other laser-induced spectroscopy instruments, such as Raman and fluorescence spectroscopy. We have developed a prototype remote LIBS-Raman-fluorescence instrument, Q-switched laser-induced time-resolved spectroscopy (QuaLITy), which is approximately 70 000 times more efficient at recording signals than a commercially available LIBS instrument. The increase in detection limits and sensitivity is due to our development of a directly coupled system, the use of an intensified charge-coupled device image detector, and a pulsed laser that allows for time-resolved measurements. We compare the LIBS capabilities of our system with an Ocean Optics spectrometer instrument at 7 m and 5 m distance. An increase in signal-to-noise ratio of at least an order of magnitude allows for greater quantitative analysis of the elements in a LIBS spectrum with 200-300 μm spatial resolution at 7 m, a Raman instrument capable of 1 mm spatial resolution at 3 m, and bioorganic fluorescence detection at longer distances. Thus, the new QuaLITy instrument fulfills all of the NASA expectations for proposed instruments.

CO2-laser micromachining and back-end processing for rapid production of PMMA-based microfluidic systems

DEFF Research Database (Denmark)

Klank, Henning; Kutter, Jörg Peter; Geschke, Oliver

2002-01-01

, a three-layer polymer microstructure with included optical fibers was fabricated within two days. The use of CO2-laser systems to produce microfluidic systems has not been published before. These systems provide a cost effective alternative to UV-laser systems and they are especially useful......In this article, we focus on the enormous potential of a CO2-laser system for rapidly producing polymer microfluidic structures. The dependence was assessed of the depth and width of laser-cut channels on the laser beam power and on the number of passes of the beam along the same channel...... for microstructured PMMA [poly( methyl methacrylate)] parts were investigated, such as solvent-assisted glueing, melting, laminating and surface activation using a plasma asher. A solvent-assisted thermal bonding method proved to be the most time-efficient one. Using laser micromachining together with bonding...

Development of a component centered fault monitoring and diagnosis knowledge based system for space power system