Design of a picosecond-laser-driven Ni-like Mo x-ray laser near 20 nm

International Nuclear Information System (INIS)

Nilsen, J.

1997-01-01

The gain is predicted for a solid molybdenum target illuminated by several joules of combined energy from a nanosecond laser pulse to create a preplasma followed by a picosecond laser pulse to drive the gain. Gains greater than 300cm -1 are predicted for the Ni-like Mo 4d 1 S 0 →4p 1 P 1 transition at 18.9 nm, which is driven by the monopole collisional excitation. High gain is also predicted for a self-photo-pumped 4f 1 P 1 →4d 1 P 1 transition at 22.0 nm and several other transitions driven by inner shell collisional ionization. copyright 1997 Optical Society of America

Recent developments in laser-driven polarized sources

International Nuclear Information System (INIS)

Young, L.; Coulter, K.P.; Holt, R.J.; Kinney, E.R.; Kowalczyk, R.S.; Potterveld, D.H.; Zghiche, A.

1990-01-01

Recent progress in the performance of laser-driven sources of polarized hydrogen and deuterium is described. The current status of the prototype source, I = 2.5 x 10 17 s -1 , polarization = 0.29 (including atomic fraction), is comparable to classical Stern-Gerlach sources. A scheme to improve source performance by approximately an order of magnitude, using a combination of optical-pumping spin-exchange and RF transitions, is outlined. 8 refs., 2 figs., 1 tab

Laser-driven polarized H/D sources and targets

International Nuclear Information System (INIS)

Clasie, B.; Crawford, C.; Dutta, D.; Gao, H.; Seely, J.; Xu, W.

2005-01-01

Traditionally, Atomic Beam Sources are used to produce targets of nuclear polarized hydrogen (H) or deuterium (D) for experiments using storage rings. Laser-Driven Sources (LDSs) offer a factor of 20-30 gain in the target thickness (however, with lower polarization) and may produce a higher overall figure of merit. The LDS is based on the technique of spin-exchange optical pumping where alkali vapor is polarized by absorbing circularly polarized laser photons. The H or D atoms are nuclear-polarized through spin-exchange collisions with the polarized alkali vapor and through subsequent hyperfine interactions during frequent H-H or D-D collisions

Tunable laser optics

CERN Document Server

Duarte, FJ

2015-01-01

This Second Edition of a bestselling book describes the optics and optical principles needed to build lasers. It also highlights the optics instrumentation necessary to characterize laser emissions and focuses on laser-based optical instrumentation. The book emphasizes practical and utilitarian aspects of relevant optics including the essential theory. This revised, expanded, and improved edition contains new material on tunable lasers and discusses relevant topics in quantum optics.

Proposal of laser-driven automobile

Science.gov (United States)

Yabe, Takashi; Oozono, Hirokazu; Taniguchi, Kazumoto; Ohkubo, Tomomasa; Miyazaki, Sho; Uchida, Shigeaki; Baasandash, Choijil

2004-09-01

We propose an automobile driven by piston motion, which is driven by water-laser coupling. The automobile can load a solar-pumped fiber laser or can be driven by ground-based lasers. The vehicle is much useful for the use in other planet in which usual combustion engine cannot be used. The piston is in a closed system and then the water will not be exhausted into vacuum. In the preliminary experiment, we succeeded to drive the cylindrical piston of 0.2g (6mm in diameter) on top of water placed inside the acrylic pipe of 8 mm in inner diameter and the laser is incident from the bottom and focused onto the upper part of water by the lens (f=8mm) attached to the bottom edge.

Applications of laser-driven particle acceleration

CERN Document Server

Parodi, Katia; Schreiber, Jorg

2018-01-01

The first book of its kind to highlight the unique capabilities of laser-driven acceleration and its diverse potential, Applications of Laser-Driven Particle Acceleration presents the basic understanding of acceleration concepts and envisioned prospects for selected applications. As the main focus, this new book explores exciting and diverse application possibilities, with emphasis on those uniquely enabled by the laser driver that can also be meaningful and realistic for potential users. A key aim of the book is to inform multiple, interdisciplinary research communities of the new possibilities available and to inspire them to engage with laser-driven acceleration, further motivating and advancing this developing field. Material is presented in a thorough yet accessible manner, making it a valuable reference text for general scientific and engineering researchers who are not necessarily subject matter experts. Applications of Laser-Driven Particle Acceleration is edited by Professors Paul R. Bolton, Katia ...

Acumulating regions of winding periodic orbits in optically driven lasers

NARCIS (Netherlands)

Krauskopf, B.; Wieczorek, S.

2002-01-01

We investigate the route to locking in class B lasers subject to optically injected light for injection strengths and detunings near a codimension-two saddle-node Hopf point. This is the parameter region where the Adler approximation is not valid and where Yeung and Strogatz recently reported a

Recent advances in laser-driven neutron sources

Science.gov (United States)

Alejo, A.; Ahmed, H.; Green, A.; Mirfayzi, S. R.; Borghesi, M.; Kar, S.

2016-11-01

Due to the limited number and high cost of large-scale neutron facilities, there has been a growing interest in compact accelerator-driven sources. In this context, several potential schemes of laser-driven neutron sources are being intensively studied employing laser-accelerated electron and ion beams. In addition to the potential of delivering neutron beams with high brilliance, directionality and ultra-short burst duration, a laser-driven neutron source would offer further advantages in terms of cost-effectiveness, compactness and radiation confinement by closed-coupled experiments. Some of the recent advances in this field are discussed, showing improvements in the directionality and flux of the laser-driven neutron beams.

The Argonne laser-driven D target: Recent developments and progress

International Nuclear Information System (INIS)

Fedchak, J.A.; Bailey, K.; Cummings, W.J.

1997-01-01

The first direct measurements of nuclear tensor polarization p zz in a laser-driven polarized D target have been performed at Argonne. We present p zz and electron polarization P e data taken at a magnetic field of 600 G in the optical pumping cell. These results are highly indicative that spin-temperature equilibrium is achieved in the system. To prevent spin relaxation of D and K atoms as well as the molecular recombination of D atoms, the walls of the laser-driven D target are coated with organosilane compounds. We discuss a new coating technique, the open-quotes afterwashclose quotes, developed at Argonne which has yielded stable atomic fraction results when the coating is exposed to K. We also present new coating techniques for glass and Cu substrates

Optically Driven Mobile Integrated Micro-Tools for a Lab-on-a-Chip

Directory of Open Access Journals (Sweden)

Yi-Jui Liu

2013-04-01

Full Text Available This study proposes an optically driven complex micromachine with an Archimedes microscrew as the mechanical power, a sphere as a coupler, and three knives as the mechanical tools. The micromachine is fabricated by two-photon polymerization and is portably driven by optical tweezers. Because the microscrew can be optically trapped and rotates spontaneously, it provides driving power for the complex micro-tools. In other words, when a laser beam focuses on the micromachine, the microscrew is trapped toward the focus point and simultaneously rotates. A demonstration showed that the integrated micromachines are grasped by the optical tweezers and rotated by the Archimedes screw. The rotation efficiencies of the microrotors with and without knives are 1.9 rpm/mW and 13.5 rpm/mW, respectively. The micromachine can also be portably dragged along planed routes. Such Archimedes screw-based optically driven complex mechanical micro-tools enable rotation similar to moving machines or mixers, which could contribute to applications for a biological microfluidic chip or a lab-on-a-chip.

Particle damage sources for fused silica optics and their mitigation on high energy laser systems.

Science.gov (United States)

Bude, J; Carr, C W; Miller, P E; Parham, T; Whitman, P; Monticelli, M; Raman, R; Cross, D; Welday, B; Ravizza, F; Suratwala, T; Davis, J; Fischer, M; Hawley, R; Lee, H; Matthews, M; Norton, M; Nostrand, M; VanBlarcom, D; Sommer, S

2017-05-15

High energy laser systems are ultimately limited by laser-induced damage to their critical components. This is especially true of damage to critical fused silica optics, which grows rapidly upon exposure to additional laser pulses. Much progress has been made in eliminating damage precursors in as-processed fused silica optics (the advanced mitigation process, AMP3), and very high damage resistance has been demonstrated in laboratory studies. However, the full potential of these improvements has not yet been realized in actual laser systems. In this work, we explore the importance of additional damage sources-in particular, particle contamination-for fused silica optics fielded in a high-performance laser environment, the National Ignition Facility (NIF) laser system. We demonstrate that the most dangerous sources of particle contamination in a system-level environment are laser-driven particle sources. In the specific case of the NIF laser, we have identified the two important particle sources which account for nearly all the damage observed on AMP3 optics during full laser operation and present mitigations for these particle sources. Finally, with the elimination of these laser-driven particle sources, we demonstrate essentially damage free operation of AMP3 fused silica for ten large optics (a total of 12,000 cm 2 of beam area) for shots from 8.6 J/cm 2 to 9.5 J/cm 2 of 351 nm light (3 ns Gaussian pulse shapes). Potentially many other pulsed high energy laser systems have similar particle sources, and given the insight provided by this study, their identification and elimination should be possible. The mitigations demonstrated here are currently being employed for all large UV silica optics on the National Ignition Facility.

Comparison of optical transients during the picosecond laser pulse-induced crystallization of GeSbTe and AgInSbTe phase-change thin films: Nucleation-driven versus growth-driven processes

Energy Technology Data Exchange (ETDEWEB)

Liang, Guangfei [Key Laboratory of High Power Laser Materials, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Li, Simian [State Key Laboratory of Optoelectronic Materials and Technology, Department of Physics, Sun Yat-Sen University, Guangzhou 510275 (China); Huang, Huan [Key Laboratory of High Power Laser Materials, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Wang, Yang, E-mail: ywang@siom.ac.cn [Key Laboratory of High Power Laser Materials, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Lai, Tianshu, E-mail: stslts@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technology, Department of Physics, Sun Yat-Sen University, Guangzhou 510275 (China); Wu, Yiqun [Key Laboratory of High Power Laser Materials, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China)

2013-09-01

Direct comparison of the real-time in-situ crystallization behavior of as-deposited amorphous Ge{sub 2}Sb{sub 2}Te{sub 5} (GeSbTe) and Ag{sub 8}In{sub 14}Sb{sub 55}Te{sub 23} (AgInSbTe) phase-change thin films driven by picosecond laser pulses was performed by a time-resolved optical pump-probe technique with nanosecond resolution. Different optical transients showed various crystallization processes because of the dissimilar nucleation- and growth-dominated mechanisms of the two materials. The effects of laser pulse fluence, thermal conductive structure, and successive pulse irradiation on their crystallization dynamics were also discussed. A schematic was then established to describe the different crystallization processes beginning from the as-deposited amorphous state. The results may provide further insight into the phase-change mechanism under extra-non-equilibrium conditions and aid the development of ultrafast phase-change memory materials.

Half-period optical pulse generation using a free-electron laser

International Nuclear Information System (INIS)

Jaroszynski, D.A.; Chaix, P.; Piovella, N.

1995-01-01

Recently there has been growth, in interest in non-equilibrium interaction of half-period long optical pulses with matter. To date the optical pulses have been produced by chopping out a half-period long segment from a longer pulse using a semiconductor switch driven by a femtosecond laser. In this paper we present new methods for producing tunable ultra-short optical pulses as short as half an optical period using a free-electron laser driven by electron bunches with a duration a fraction of an optical period. Two different methods relying on the production of coherent spontaneous emission will be described. In the first method we show that when a train of ultra-short optical pulses as short as one half period. We present calculations which show that the small signal gain is unimportant in the early stages of radiation build up in the cavity when the startup process is dominated by coherent spontaneous emission. To support our proposed method we present encouraging experimental results from the FELIX experiment in the Netherlands which show that interference effects between the coherent spontaneous optical pulses at start-up are very important. The second proposed method relies on the fact that coherent spontaneous emission mimics the undulations of electrons as they pass through the undulator. We show that ultra-short optical pulses are produced by coherent spontaneous emission when ultra-short electron bunches pass through an ultra-short undulator. We discuss the interesting case of such undulator radiation in the presence of an optical cavity and show that the optical pulse can be open-quotes tayloredclose quotes by simply adjusting the optical cavity desynchronism. The proposed methods may be realisable using existing rf driven FELs in the far-infrared

Direct Laser-Driven Quasi-Isentropic Compression on HEAVEN-I Laser

International Nuclear Information System (INIS)

Zhang Pin-Liang; Tang Xiu-Zhang; Li Ye-Jun; Wang Zhao; Tian Bao-Xian; Yin Qian; Lu Ze; Xiang Yi-Huai; Gao Zhi-Xing; Li Jing; Hu Feng-Ming; Gong Zi-Zheng

2015-01-01

The HEAVEN-I laser is used for direct drive quasi-isentropic compression up to ∼18 GPa in samples of aluminum without being temporal pulse shaped. The monotonically increasing loading is with a rise time over 17 ns. The compression history is well reproduced by the 1D radiation hydrodynamics simulation. We find that a small shock precursor where the backward integration method cannot process is formed at the beginning of illumination. We compare the loading process of HEAVEN-I with the typical profile (concave down, prefect pulse shape), the results show that a typical profile can obtain more slowly rising and higher pressure, and the shock precursor has significant effects on temperature and entropy production. However, it is demonstrated that the HEAVEN-I is an excellent optical source for direct laser-driven quasi-isentropic compression, even if it produces more temperature rise and entropy than the typical profile. (paper)

Solitary pulse-on-demand production by optical injection locking of passively Q-switched InGaN diode laser near lasing threshold

Energy Technology Data Exchange (ETDEWEB)

Zeng, X., E-mail: xi.zeng@csem.ch, E-mail: dmitri.boiko@csem.ch; Stadelmann, T.; Grossmann, S.; Hoogerwerf, A. C.; Boïko, D. L., E-mail: xi.zeng@csem.ch, E-mail: dmitri.boiko@csem.ch [Centre Suisse d' Electronique et de Microtechnique SA (CSEM), CH-2002 Neuchâtel (Switzerland); Sulmoni, L.; Lamy, J.-M.; Grandjean, N. [Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

2015-02-16

In this letter, we investigate the behavior of a Q-switched InGaN multi-section laser diode (MSLD) under optical injection from a continuous wave external cavity diode laser. We obtain solitary optical pulse generation when the slave MSLD is driven near free running threshold, and the peak output power is significantly enhanced with respect to free running configuration. When the slave laser is driven well above threshold, optical injection reduces the peak power. Using standard semiconductor laser rate equation model, we find that both power enhancement and suppression effects are the result of partial bleaching of the saturable absorber by externally injected photons.

Generation of Raman lasers from nitrogen molecular ions driven by ultraintense laser fields

Science.gov (United States)

Yao, Jinping; Chu, Wei; Liu, Zhaoxiang; Xu, Bo; Chen, Jinming; Cheng, Ya

2018-03-01

Atmospheric lasing has aroused much interest in the past few years. The ‘air–laser’ opens promising potential for remote chemical sensing of trace gases with high sensitivity and specificity. At present, several approaches have been successfully implemented for generating highly coherent laser beams in atmospheric condition, including both amplified-spontaneous emission, and narrow-bandwidth stimulated emission in the forward direction in the presence of self-generated or externally injected seed pulses. Here, we report on generation of multiple-wavelength Raman lasers from nitrogen molecular ions ({{{N}}}2+), driven by intense mid-infrared laser fields. Intuitively, the approach appears problematic for the small nonlinear susceptibility of {{{N}}}2+ ions, whereas the efficiency of Raman laser can be significantly promoted in near-resonant condition. More surprisingly, a Raman laser consisting of a supercontinuum spanning from ∼310 to ∼392 nm has been observed resulting from a series near-resonant nonlinear processes including four-wave mixing, stimulated Raman scattering and cross phase modulation. To date, extreme nonlinear optics in molecular ions remains largely unexplored, which provides an alternative means for air–laser-based remote sensing applications.

Laser-sheet imaging of HE-driven interfaces

International Nuclear Information System (INIS)

Benjamin, R.F.; Rightley, P.M.; Kinkead, S.; Martin, R.A.; Critchfield, R.; Sandoval, D.L.; Holmes, R.; Gorman, T.

1998-01-01

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The authors made substantial progress in developing the MILSI (Multiple Imaging of Laser-Sheet Illumination) technique for high explosive (HE)-driven fluid interfaces. They observed the instability, but have not yet measured the instability growth rate. They developed suitable sample containers and optical systems for studying the Rightmyer-Meshkov instability of perturbed water/bromoform interfaces and they successfully fielded the new MILSI diagnostic at two firing-site facilities. The problem continues to be of central importance to the inertial confinement fusion (ICF) and weapons physics communities

The ELIMED transport and dosimetry beamline for laser-driven ion beams

Energy Technology Data Exchange (ETDEWEB)

Romano, F., E-mail: francesco.romano@lns.infn.it [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Schillaci, F.; Cirrone, G.A.P.; Cuttone, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Scuderi, V. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); ELI-Beamlines Project, Institute of Physics ASCR, v.v.i. (FZU), 182 21 Prague (Czech Republic); Allegra, L.; Amato, A.; Amico, A.; Candiano, G.; De Luca, G.; Gallo, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Giordanengo, S.; Guarachi, L. Fanola [Istituto Nazionale di Fisica Nucleare, Sezione di Torino, Via P. Giuria 1, Torino (Italy); Universita' di Torino, Dipartimento di Fisica, Via P. Giuria 1, Torino (Italy); Korn, G. [ELI-Beamlines Project, Institute of Physics ASCR, v.v.i. (FZU), 182 21 Prague (Czech Republic); Larosa, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Leanza, R. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Universita' di Catania, Dipartimento di Fisica e Astronomia, Via S. Sofia 64, Catania (Italy); Manna, R.; Marchese, V. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Marchetto, F. [Istituto Nazionale di Fisica Nucleare, Sezione di Torino, Via P. Giuria 1, Torino (Italy); Margarone, D. [ELI-Beamlines Project, Institute of Physics ASCR, v.v.i. (FZU), 182 21 Prague (Czech Republic); and others

2016-09-01

A growing interest of the scientific community towards multidisciplinary applications of laser-driven beams has led to the development of several projects aiming to demonstrate the possible use of these beams for therapeutic purposes. Nevertheless, laser-accelerated particles differ from the conventional beams typically used for multiscipilinary and medical applications, due to the wide energy spread, the angular divergence and the extremely intense pulses. The peculiarities of optically accelerated beams led to develop new strategies and advanced techniques for transport, diagnostics and dosimetry of the accelerated particles. In this framework, the realization of the ELIMED (ELI-Beamlines MEDical and multidisciplinary applications) beamline, developed by INFN-LNS (Catania, Italy) and that will be installed in 2017 as a part of the ELIMAIA beamline at the ELI-Beamlines (Extreme Light Infrastructure Beamlines) facility in Prague, has the aim to investigate the feasibility of using laser-driven ion beams for multidisciplinary applications. In this contribution, an overview of the beamline along with a detailed description of the main transport elements as well as the detectors composing the final section of the beamline will be presented.

Development of Z-pinch optical guiding for laser-plasma accelerator

International Nuclear Information System (INIS)

Hosokai, Tomonao; Kando, Masaki; Dewa, Hideki; Kotaki, Hideyuki; Kondo, Shuji; Kanazawa, Shuhei; Nakajima, Kazuhisa; Horioka, Kazuhiko

2000-01-01

We have proposed optical guiding of intense laser pulse by fast Z-pinch for channel guided laser wakefield acceleration (LWFA). It has been developed based on capillary discharge-pumped X-ray laser technique. The discharge driven by current of 4.8 kA with a rise time of 15 ns through preionized helium gas could produce an uniform guiding channel with good reproducibility. With this new guiding method an intense Ti-Sapphire laser pulse (λ=790 nm, 2.2 TW, 90 fs, 1 x 10 17 W/cm 2 ) was transported through the channel over a distance of 2 cm corresponding to 12.5 times the Rayleigh length. (author)

All-optical spinor Bose-Einstein condensation and the spinor dynamics-driven atom laser

Science.gov (United States)

Lundblad, Nathan Eric

Optical trapping as a viable means of exploring the physics of ultracold dilute atomic gases has revealed a new spectrum of physical phenomena. In particular, macroscopic and sudden occupation of the ground state below a critical temperature---a phenomenon known as Bose-Einstein condensation---has become an even richer system for the study of quantum mechanics, ultracold collisions, and many-body physics in general. Optical trapping liberates the spin degree of the BEC, making the order parameter vectorial ('spinor BEC'), as opposed to the scalar order of traditional magnetically trapped condensates. The work described within is divided into two main efforts. The first encompasses the all-optical creation of a Bose-Einstein condensate in rubidium vapor. An all-optical path to spinor BEC (as opposed to transfer to an optical trap from a magnetic trap condensate) was desired both for the simplicity of the experimental setup and also for the potential gains in speed of creation; evaporative cooling, the only known path to dilute-gas condensation, works only as efficiently as the rate of elastic collisions in the gas, a rate that starts out much higher in optical traps. The first all-optical BEC was formed elsewhere in 2001; the years following saw many groups worldwide seeking to create their own version. Our own all-optical spinor BEC, made with a single-beam dipole trap formed by a focused CO2 laser, is described here, with particular attention paid to trap loading, measurement of trap parameters, and the use of a novel 780 nm high-power laser system. The second part describes initial experiments performed with the nascent condensate. The spinor properties of the condensate are documented, and a measurement is made of the density-dependent rate of spin mixing in the condensate. In addition, we demonstrate a novel dual-beam atom laser formed by outcoupling oppositely polarized components of the condensate, whose populations have been coherently evolved through spin

Laser-driven acceleration with Bessel beam

International Nuclear Information System (INIS)

Imasaki, Kazuo; Li, Dazhi

2005-01-01

A new approach of laser-driven acceleration with Bessel beam is described. Bessel beam, in contrast to the Gaussian beam, shows diffraction-free'' characteristics in its propagation, which implies potential in laser-driven acceleration. But a normal laser, even if the Bessel beam, laser can not accelerate charged particle efficiently because the difference of velocity between the particle and photon makes cyclic acceleration and deceleration phase. We proposed a Bessel beam truncated by a set of annular slits those makes several special regions in its travelling path, where the laser field becomes very weak and the accelerated particles are possible to receive no deceleration as they undergo decelerating phase. Thus, multistage acceleration is realizable with high gradient. In a numerical computation, we have shown the potential of multistage acceleration based on a three-stage model. (author)

Optical and plasma smoothing of laser imprinting in targets driven by lasers with SSD bandwidths up to 1 THz

International Nuclear Information System (INIS)

Boehly, T.R.; Goncharov, V.N.; Gotchev, O.; Knauer, J.P.; Meyerhofer, D.D.; Oron, D.; Regan, S.P.; Srebro, Y.; Seka, W.; Shvarts, D.; Skupsky, S.; Smalyuk, V.A.

2001-01-01

The creation of a plasma atmosphere in laser-target interactions increases the distance between the regions of laser absorption and hydrodynamic instability (ablation front), thus allowing thermal smoothing and a reduction of laser-imprinted modulations that reach the unstable ablation region. The total laser imprinting is reduced with pulse shapes that produce a plasma atmosphere more rapidly and by the implementation of temporal beam smoothing. These effects are measured and found to be consistent with models for the hydrodynamics and optical smoothing by spectral dispersion (SSD). Imprinting is reduced as the laser bandwidth is increased from 0.2 to 1.0 THz

Laser driven source of spin polarized atomic deuterium and hydrogen

International Nuclear Information System (INIS)

Poelker, M.; Coulter, K.P.; Holt, R.J.

1993-01-01

Optical pumping of potassium atoms in the presence of a high magnetic field followed by spin exchange collisions with deuterium (hydrogen) is shown to yield a high flux of spin polarized atomic deuterium (hydrogen). The performance of the laser driven source has been characterized as a function of deuterium (hydrogen) flow rate, potassium density, pump laser power, and magnetic field. Under appropriate conditions, the authors have observed deuterium atomic polarization as high as 75% at a flow rate 4.2x10 17 atoms/second. Preliminary results suggest that high nuclear polarizations are obtained in the absence of weak field rf transitions as a result of a spin temperature distribution that evolves through frequent H-H (D-D) collisions

Targeted femtosecond laser driven drug delivery within HIV-1 infected cells: In-vitro studies [conference paper

CSIR Research Space (South Africa)

Maphanga, Charles

2017-01-01

Full Text Available of SPIE 10062, Optical Interactions with Tissue and Cells XXVIIISan Francisco, California, USA, 26 January - 03 February 2017 Targeted femtosecond laser driven drug delivery within HIV-1 infected cells: In-vitro studies Charles Maphanga 1, 2...

Time of Flight based diagnostics for high energy laser driven ion beams

Science.gov (United States)

Scuderi, V.; Milluzzo, G.; Alejo, A.; Amico, A. G.; Booth, N.; Cirrone, G. A. P.; Doria, D.; Green, J.; Kar, S.; Larosa, G.; Leanza, R.; Margarone, D.; McKenna, P.; Padda, H.; Petringa, G.; Pipek, J.; Romagnani, L.; Romano, F.; Schillaci, F.; Borghesi, M.; Cuttone, G.; Korn, G.

2017-03-01

Nowadays the innovative high power laser-based ion acceleration technique is one of the most interesting challenges in particle acceleration field, showing attractive characteristics for future multidisciplinary applications, including medical ones. Nevertheless, peculiarities of optically accelerated ion beams make mandatory the development of proper transport, selection and diagnostics devices in order to deliver stable and controlled ion beams for multidisciplinary applications. This is the main purpose of the ELIMAIA (ELI Multidisciplinary Applications of laser-Ion Acceleration) beamline that will be realized and installed within 2018 at the ELI-Beamlines research center in the Czech Republic, where laser driven high energy ions, up to 60 MeV/n, will be available for users. In particular, a crucial role will be played by the on-line diagnostics system, recently developed in collaboration with INFN-LNS (Italy), consisting of TOF detectors, placed along the beamline (at different detection distances) to provide online monitoring of key characteristics of delivered beams, such as energy, fluence and ion species. In this contribution an overview on the ELIMAIA available ion diagnostics will be briefly given along with the preliminary results obtained during a test performed with high energy laser-driven proton beams accelerated at the VULCAN PW-laser available at RAL facility (U.K.).

Time of Flight based diagnostics for high energy laser driven ion beams

International Nuclear Information System (INIS)

Scuderi, V.; Margarone, D.; Schillaci, F.; Milluzzo, G.; Amico, A.G.; Cirrone, G.A.P.; Larosa, G.; Leanza, R.; Petringa, G.; Pipek, J.; Romano, F.; Alejo, A.; Doria, D.; Kar, S.; Borghesi, M.; Booth, N.; Green, J.; McKenna, P.; Padda, H.; Romagnani, L.

2017-01-01

Nowadays the innovative high power laser-based ion acceleration technique is one of the most interesting challenges in particle acceleration field, showing attractive characteristics for future multidisciplinary applications, including medical ones. Nevertheless, peculiarities of optically accelerated ion beams make mandatory the development of proper transport, selection and diagnostics devices in order to deliver stable and controlled ion beams for multidisciplinary applications. This is the main purpose of the ELIMAIA (ELI Multidisciplinary Applications of laser-Ion Acceleration) beamline that will be realized and installed within 2018 at the ELI-Beamlines research center in the Czech Republic, where laser driven high energy ions, up to 60 MeV/n, will be available for users. In particular, a crucial role will be played by the on-line diagnostics system, recently developed in collaboration with INFN-LNS (Italy), consisting of TOF detectors, placed along the beamline (at different detection distances) to provide online monitoring of key characteristics of delivered beams, such as energy, fluence and ion species. In this contribution an overview on the ELIMAIA available ion diagnostics will be briefly given along with the preliminary results obtained during a test performed with high energy laser-driven proton beams accelerated at the VULCAN PW-laser available at RAL facility (U.K.).

Polydopamine-Coated Main-Chain Liquid Crystal Elastomer as Optically Driven Artificial Muscle.

Science.gov (United States)

Tian, Hongmiao; Wang, Zhijian; Chen, Yilong; Shao, Jinyou; Gao, Tong; Cai, Shengqiang

2018-03-07

Optically driven active materials have received much attention because their deformation and motion can be controlled remotely, instantly, and precisely in a contactless way. In this study, we investigated an optically actuated elastomer with rapid response: polydopamine (PDA)-coated liquid crystal elastomer (LCE). Because of the photothermal effect of PDA coating and thermal responsiveness of LCE, the elastomer film contracted significantly with near-infrared (NIR) irradiation. With a fixed strain, light-induced actuating stress in the film could be as large as 1.5 MPa, significantly higher than the maximum stress generated by most mammalian skeletal muscle (0.35 MPa). The PDA-coated LCE films could also bend or roll up by surface scanning of an NIR laser. The response time of the film to light exposure could be as short as 1/10 of a second, comparable to or even faster than that of mammalian skeletal muscle. Using the PDA-coated LCE film, we designed and fabricated a prototype of robotic swimmer that was able to swim near the water-air interface by performing "swimming strokes" through reversible bending and unbending motions induced and controlled by an NIR laser. The results presented in this study clearly demonstrated that PDA-coated LCE is a promising optically driven artificial muscle, which may have great potential for applications of soft robotics and optomechanical coupling devices.

Controllable optical bistability in photonic-crystal one-atom laser

International Nuclear Information System (INIS)

Guo Xiaoyong; Lue Shuchen

2009-01-01

We investigate the property of optical bistability in a photonic-crystal one-atom laser when nonlinear microcavity is present. The physical system consists of a coherently driven two-level light emitter strongly coupled to a high-quality microcavity which is embedded within a photonic crystal and another coherent probing field which has incident into the microcavity. In our case, the microcavity is fabricated by nonlinear material and placed as an impurity in photonic crystal. This study reveals that such a system can exhibit optical bistability. The dependence of threshold value and hysteresis loop on the photonic band gap of the photonic crystal, driving field Rabi frequency and dephasing processes, are studied. Our results clearly illustrate the ability to control optical bistability through suitable photonic-crystal architectures and external coherent driving field, and this study suggests that in a photonic-crystal nonlinear microcavity, the one-atom laser acts as an effective controllable bistable device in the design of all-light digital computing systems in the near future.

Laser-Driven Mini-Thrusters

International Nuclear Information System (INIS)

Sterling, Enrique; Lin Jun; Sinko, John; Kodgis, Lisa; Porter, Simon; Pakhomov, Andrew V.; Larson, C. William; Mead, Franklin B. Jr.

2006-01-01

Laser-driven mini-thrusters were studied using Delrin registered and PVC (Delrin registered is a registered trademark of DuPont) as propellants. TEA CO2 laser (λ = 10.6 μm) was used as a driving laser. Coupling coefficients were deduced from two independent techniques: force-time curves measured with a piezoelectric sensor and ballistic pendulum. Time-resolved ICCD images of the expanding plasma and combustion products were analyzed in order to determine the main process that generates the thrust. The measurements were also performed in a nitrogen atmosphere in order to test the combustion effects on thrust. A pinhole transmission experiment was performed for the study of the cut-off time when the ablation/air breakdown plasma becomes opaque to the incoming laser pulse

Laser-Driven Mini-Thrusters

Science.gov (United States)

Sterling, Enrique; Lin, Jun; Sinko, John; Kodgis, Lisa; Porter, Simon; Pakhomov, Andrew V.; Larson, C. William; Mead, Franklin B.

2006-05-01

Laser-driven mini-thrusters were studied using Delrin® and PVC (Delrin® is a registered trademark of DuPont) as propellants. TEA CO2 laser (λ = 10.6 μm) was used as a driving laser. Coupling coefficients were deduced from two independent techniques: force-time curves measured with a piezoelectric sensor and ballistic pendulum. Time-resolved ICCD images of the expanding plasma and combustion products were analyzed in order to determine the main process that generates the thrust. The measurements were also performed in a nitrogen atmosphere in order to test the combustion effects on thrust. A pinhole transmission experiment was performed for the study of the cut-off time when the ablation/air breakdown plasma becomes opaque to the incoming laser pulse.

Optical pulse generation using fiber lasers and integrated optics

International Nuclear Information System (INIS)

Wilcox, R.B.; Browning, D.F.; Burkhart, S.C.; VanWonterghem, B.W.

1995-01-01

We have demonstrated an optical pulse forming system using fiber and integrated optics, and have designed a multiple-output system for a proposed fusion laser facility. Our approach is an advancement over previous designs for fusion lasers, and an unusual application of fiber lasers and integrated optics

Progress of Laser-Driven Plasma Accelerators

International Nuclear Information System (INIS)

Nakajima, Kazuhisa

2007-01-01

There is a great interest worldwide in plasma accelerators driven by ultra-intense lasers which make it possible to generate ultra-high gradient acceleration and high quality particle beams in a much more compact size compared with conventional accelerators. A frontier research on laser and plasma accelerators is focused on high energy electron acceleration and ultra-short X-ray and Tera Hertz radiations as their applications. These achievements will provide not only a wide range of sciences with benefits of a table-top accelerator but also a basic science with a tool of ultrahigh energy accelerators probing an unknown extremely microscopic world.Harnessing the recent advance of ultra-intense ultra-short pulse lasers, the worldwide research has made a tremendous breakthrough in demonstrating high-energy high-quality particle beams in a compact scale, so called ''dream beams on a table top'', which represents monoenergetic electron beams from laser wakefield accelerators and GeV acceleration by capillary plasma-channel laser wakefield accelerators. This lecture reviews recent progress of results on laser-driven plasma based accelerator experiments to quest for particle acceleration physics in intense laser-plasma interactions and to present new outlook for the GeV-range high-energy laser plasma accelerators

Laser-driven ion acceleration: methods, challenges and prospects

Science.gov (United States)

Badziak, J.

2018-01-01

The recent development of laser technology has resulted in the construction of short-pulse lasers capable of generating fs light pulses with PW powers and intensities exceeding 1021 W/cm2, and has laid the basis for the multi-PW lasers, just being built in Europe, that will produce fs pulses of ultra-relativistic intensities ~ 1023 - 1024 W/cm2. The interaction of such an intense laser pulse with a dense target can result in the generation of collimated beams of ions of multi-MeV to GeV energies of sub-ps time durations and of extremely high beam intensities and ion fluencies, barely attainable with conventional RF-driven accelerators. Ion beams with such unique features have the potential for application in various fields of scientific research as well as in medical and technological developments. This paper provides a brief review of state-of-the art in laser-driven ion acceleration, with a focus on basic ion acceleration mechanisms and the production of ultra-intense ion beams. The challenges facing laser-driven ion acceleration studies, in particular those connected with potential applications of laser-accelerated ion beams, are also discussed.

Ionization and bound-state relativistic quantum dynamics in laser-driven multiply charged ions

International Nuclear Information System (INIS)

Hetzheim, Henrik

2009-01-01

The interaction of ultra-strong laser fields with multiply charged hydrogen-like ions can be distinguished in an ionization and a bound dynamics regime. Both are investigated by means of numerically solving the Dirac equation in two dimensions and by a classical relativistic Monte-Carlo simulation. For a better understanding of highly nonlinear physical processes the development of a well characterized ultra-intense relativistic laser field strength has been driven forward, capable of studying e.g. the magnetic field effects of the laser resulting in an additional electron motion in the laser propagation direction. A novel method to sensitively measure these ultra-strong laser intensities is developed and employed from the optical via the UV towards the XUV frequency regime. In the bound dynamics field, the determination of multiphoton transition matrixelements has been investigated between different bound states via Rabi oscillations. (orig.)

Ionization and bound-state relativistic quantum dynamics in laser-driven multiply charged ions

Energy Technology Data Exchange (ETDEWEB)

Hetzheim, Henrik

2009-01-14

The interaction of ultra-strong laser fields with multiply charged hydrogen-like ions can be distinguished in an ionization and a bound dynamics regime. Both are investigated by means of numerically solving the Dirac equation in two dimensions and by a classical relativistic Monte-Carlo simulation. For a better understanding of highly nonlinear physical processes the development of a well characterized ultra-intense relativistic laser field strength has been driven forward, capable of studying e.g. the magnetic field effects of the laser resulting in an additional electron motion in the laser propagation direction. A novel method to sensitively measure these ultra-strong laser intensities is developed and employed from the optical via the UV towards the XUV frequency regime. In the bound dynamics field, the determination of multiphoton transition matrixelements has been investigated between different bound states via Rabi oscillations. (orig.)

Photonic Crystal Laser-Driven Accelerator Structures

International Nuclear Information System (INIS)

Cowan, Benjamin M.

2007-01-01

Laser-driven acceleration holds great promise for significantly improving accelerating gradient. However, scaling the conventional process of structure-based acceleration in vacuum down to optical wavelengths requires a substantially different kind of structure. We require an optical waveguide that (1) is constructed out of dielectric materials, (2) has transverse size on the order of a wavelength, and (3) supports a mode with speed-of-light phase velocity in vacuum. Photonic crystals---structures whose electromagnetic properties are spatially periodic---can meet these requirements. We discuss simulated photonic crystal accelerator structures and describe their properties. We begin with a class of two-dimensional structures which serves to illustrate the design considerations and trade-offs involved. We then present a three-dimensional structure, and describe its performance in terms of accelerating gradient and efficiency. We discuss particle beam dynamics in this structure, demonstrating a method for keeping a beam confined to the waveguide. We also discuss material and fabrication considerations. Since accelerating gradient is limited by optical damage to the structure, the damage threshold of the dielectric is a critical parameter. We experimentally measure the damage threshold of silicon for picosecond pulses in the infrared, and determine that our structure is capable of sustaining an accelerating gradient of 300 MV/m at 1550 nm. Finally, we discuss possibilities for manufacturing these structures using common microfabrication techniques

Femtosecond laser direct-write of optofluidics in polymer-coated optical fiber

Science.gov (United States)

Joseph, Kevin A. J.; Haque, Moez; Ho, Stephen; Aitchison, J. Stewart; Herman, Peter R.

2017-03-01

Multifunctional lab in fiber technology seeks to translate the accomplishments of optofluidic, lab on chip devices into silica fibers. a robust, flexible, and ubiquitous optical communication platform that can underpin the `Internet of Things' with distributed sensors, or enable lab on chip functions deep inside our bodies. Femtosecond lasers have driven significant advances in three-dimensional processing, enabling optical circuits, microfluidics, and micro-mechanical structures to be formed around the core of the fiber. However, such processing typically requires the stripping and recoating of the polymer buffer or jacket, increasing processing time and mechanically weakening the device. This paper reports on a comprehensive assessment of laser damage in urethane-acrylate-coated fiber. The results show a sufficient processing window is available for femtosecond laser processing of the fiber without damaging the polymer jacket. The fiber core, cladding, and buffer could be simultaneously processed without removal of the buffer jacket. Three-dimensional lab in fiber devices were successfully fabricated by distortion-free immersionlens focusing, presenting fiber-cladding optical circuits and progress towards chemically-etched channels, microfluidic cavities, and MEMS structure inside buffer-coated fiber.

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.

Optics assembly for high power laser tools

Science.gov (United States)

Fraze, Jason D.; Faircloth, Brian O.; Zediker, Mark S.

2016-06-07

There is provided a high power laser rotational optical assembly for use with, or in high power laser tools for performing high power laser operations. In particular, the optical assembly finds applications in performing high power laser operations on, and in, remote and difficult to access locations. The optical assembly has rotational seals and bearing configurations to avoid contamination of the laser beam path and optics.

Optically driven self-oscillations of a silica nanospike at low gas pressures

Science.gov (United States)

Xie, Shangran; Pennetta, Riccardo; Noskov, Roman E.; Russell, Philip St. J.

2016-09-01

We report light-driven instability and optomechanical self-oscillation of a fused silica "nanospike" at low gas pressures. The nanospike (tip diameter 400 nm), fabricated by thermally tapering and HF-etching a single mode fiber (SMF), was set pointing at the endface of a hollow-core photonic crystal fiber (HC-PCF) into the field created by the fundamental optical mode emerging from the HC-PCF. At low pressures, the nanospike became unstable and began to self-oscillate for optical powers above a certain threshold, acting like a phonon laser or "phaser". Because the nanospike is robustly connected to the base, direct measurement of the temporal dynamics of the instability is possible. The experiment sheds light on why particles escape from optical traps at low pressures.

Investigation toward laser driven IFE power plant

International Nuclear Information System (INIS)

Nakai, S.; Kozaki, Y.; Izawa, Y.

2001-01-01

Inertial fusion energy (IFE) is becoming feasible due to the increasing understanding of implosion physics. Reactor technology issues have begun to be developed. Based on the conceptual design of Laser Driven IFE Power Plant, the technical and physical issues have been examined. R and D on key issues that affect the feasibility of power plant have been proceeded taking into account the collaboration in the field of laser driver, fuel pellet, reaction chamber and system design. It is concluded that the technical feasibility of IFE power plant seems to be reasonably high. Coordination and collaboration scheme of reactor technology experts in Japan on Laser Driven IFE Power Plant is being proceeded. (author)

CO2 laser and plasma microjet process for improving laser optics

Science.gov (United States)

Brusasco, Raymond M.; Penetrante, Bernardino M.; Butler, James A.; Grundler, Walter; Governo, George K.

2003-09-16

A optic is produced for operation at the fundamental Nd:YAG laser wavelength of 1.06 micrometers through the tripled Nd:YAG laser wavelength of 355 nanometers by the method of reducing or eliminating the growth of laser damage sites in the optics by processing the optics to stop damage in the optics from growing to a predetermined critical size. A system is provided of mitigating the growth of laser-induced damage in optics by virtue of very localized removal of glass and absorbing material.

Optimization of torque on an optically driven micromotor by manipulation of the index of refraction

Science.gov (United States)

Wing, Frank M., III; Mahajan, Satish; Collett, Walter

2004-12-01

Since the 1970"s, the focused laser beam has become a familiar tool to manipulate neutral, dielectric micro-objects. A number of authors, including Higurashi and Gauthier, have described the effects of radiation pressure from laser light on microrotors. Collett, et al. developed a wave, rather than a ray optic, approach in the calculation of such forces on a microrotor for the first time. This paper describes a modification to the design of a laser driven, radiation pressure microrotor, intended to improve the optically generated torque. Employing the wave approach, the electric and magnetic fields in the vicinity of the rotor are calculated using the finite difference time domain (FDTD) method, which takes into account the wave nature of the incident light. Forces are calculated from the application of Maxwell"s stress tensor over the surfaces of the rotor. Results indicate a significant increase in torque when the index of refraction of the microrotor is changed from a single value to an inhomogeneous profile. The optical fiber industry has successfully employed a variation in the index of refraction across the cross section of a fiber for the purpose of increasing the efficiency of light transmission. Therefore, it is hoped that various fabrication methods can be utilized for causing desired changes in the index of refraction of an optically driven microrotor. Various profiles of the index of refraction inside a microrotor are considered for optimization of torque. Simulation methodology and results of torque on a microrotor for various profiles of the index of refraction are presented. Guidelines for improvised fabrication of efficient microrotors may then be obtained from these profiles.

Investigations of collisionally pumped optical field ionization soft x-ray lasers

Czech Academy of Sciences Publication Activity Database

Sebban, S.; Upcraft, L. M.; Balcou, P.; Pittman, M.; Haroutunian, R.; Grillon, G.; Valentin, C.; Rousse, A.; Rousseau, J. P.; Notebaert, L.; Hulin, D.; Mocek, Tomáš; Rus, Bedřich; Ros, D.; Klisnick, A.; Carillon, A.; Jamelot, G.

2003-01-01

Roč. 20, č. 1 (2003), s. 195-202 ISSN 0740-3224 R&D Projects: GA MŠk LN00A100; GA AV ČR IAA1010014 Grant - others:HPRI(XE) CT-1999-000053 Institutional research plan: CEZ:AV0Z1010921 Keywords : femtosecond-pulse-driven * gases * recombination * amplification * generation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.122, year: 2003

Optics, light and lasers

CERN Document Server

Meschede, Dieter

2008-01-01

Starting from the concepts of classical optics, Optics, Light and Lasers introduces in detail the phenomena of linear and nonlinear light matter interaction, the properties of modern laser sources, and the concepts of quantum optics. Several examples taken from the scope of modern research are provided to emphasize the relevance of optics in current developments within science and technology. The text has been written for newcomers to the topic and benefits from the author's ability to explain difficult sequences and effects in a straightforward and easily comprehensible way. To this second, c

Gigashot Optical Laser Demonstrator

Energy Technology Data Exchange (ETDEWEB)

Deri, R. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2015-10-13

The Gigashot Optical Laser Demonstrator (GOLD) project has demonstrated a novel optical amplifier for high energy pulsed lasers operating at high repetition rates. The amplifier stores enough pump energy to support >10 J of laser output, and employs conduction cooling for thermal management to avoid the need for expensive and bulky high-pressure helium subsystems. A prototype amplifier was fabricated, pumped with diode light at 885 nm, and characterized. Experimental results show that the amplifier provides sufficient small-signal gain and sufficiently low wavefront and birefringence impairments to prove useful in laser systems, at repetition rates up to 60 Hz.

Optical fibre laser velocimetry: a review

International Nuclear Information System (INIS)

Charrett, Thomas O H; James, Stephen W; Tatam, Ralph P

2012-01-01

The applications of optical fibre technology to laser velocimetry are diverse and often critical to their successful implementation, particularly in harsh environments. Applications range from the use of optical fibres for beam delivery and scattered light collection, aiding the miniaturization of instrument probes, to the use of imaging fibre bundles for imaging the flow field in planar velocimetry systems. Optical fibre techniques have also been used in signal processing, for example fibre frequency shifters, and optical fibre devices such as amplifiers and lasers have been exploited. This paper will review the use of optical fibres in point-wise laser velocimetry techniques such as laser Doppler velocimetry and laser transit anemometry, as well as in planar measurement techniques such as particle imaging velocimetry and planar Doppler velocimetry. (topical review)

Electro-optic diffraction grating tuned laser

International Nuclear Information System (INIS)

Hughes, R.S.

1975-01-01

An electro-optic diffraction grating tuned laser comprising a laser medium, output mirror, retro-reflective grating and an electro-optic diffraction grating beam deflector positioned between the laser medium and the reflective diffraction grating is described. An optional angle multiplier may be used between the electro-optic diffraction grating and the reflective grating. (auth)

Measurement of the Rayleigh-Taylor instability in targets driven by optically smoothed laser beams

International Nuclear Information System (INIS)

Desselberger, M.; Willi, O.; Savage, M.; Lamb, M.J.

1990-01-01

Growth rates of the Rayleigh-Taylor instability were measured in targets with imposed sinusoidal modulations irradiated by optically smoothed 0.53-μm laser beams. A hybrid optical smoothing technique utilizing induced-spatial-incoherence and random-phase-plate technology was used for the first time. The wave-number dependence and the nonlinear behavior of Rayleigh-Taylor growth were investigated by using targets with a range of modulation periodicities and depths. The results are compared to 2D hydrodynamic-code simulations

Bistability and low-frequency fluctuations in semiconductor lasers with optical feedback: a theoretical analysis

DEFF Research Database (Denmark)

Mørk, Jesper; Tromborg, Bjarne; Christiansen, Peter Leth

1988-01-01

Near-threshold operation of a semiconductor laser exposed to moderate optical feedback may lead to low-frequency fluctuations. In the same region, a kink is observed in the light-current characteristic. Here it is demonstrated that these nonlinear phenomena are predicted by a noise driven multimode...

Spatial dynamics of picosecond CO2 laser pulses produced by optical switching in Ge

International Nuclear Information System (INIS)

Pogorelsky, I.; Fisher, A.S.; Veligdan, J.; Russell, P.

1991-01-01

The design, test and optimization of a picosecond CO 2 pulse-forming system are presented. The system switches a semiconductor's optical characteristics at 10 μm under the control of a synchronized 1.06-μm Nd:YAG picosecond laser pulse. An energy-efficient version of such a system using collimated beams is described. A simple, semi-empirical approach is used to simulate the switching process, specifically including the spatial distributions of the laser energy and phase, which are relevant for experiments in laser-driven electron acceleration. 11 refs., 7 figs

2.5 TW, two-cycle IR laser pulses via frequency domain optical parametric amplification.

Science.gov (United States)

Gruson, V; Ernotte, G; Lassonde, P; Laramée, A; Bionta, M R; Chaker, M; Di Mauro, L; Corkum, P B; Ibrahim, H; Schmidt, B E; Legaré, F

2017-10-30

Broadband optical parametric amplification in the IR region has reached a new milestone through the use of a non-collinear Frequency domain Optical Parametric Amplification system. We report a laser source delivering 11.6 fs pulses with 30 mJ of energy at a central wavelength of 1.8 μm at 10 Hz repetition rate corresponding to a peak power of 2.5 TW. The peak power scaling is accompanied by a pulse shortening of about 20% upon amplification due to the spectral reshaping with higher gain in the spectral wings. This source paves the way for high flux soft X-ray pulses and IR-driven laser wakefield acceleration.

Laser-driven ion acceleration with hollow laser beams

International Nuclear Information System (INIS)

Brabetz, C.; Kester, O.; Busold, S.; Bagnoud, V.; Cowan, T.; Deppert, O.; Jahn, D.; Roth, M.; Schumacher, D.

2015-01-01

The laser-driven acceleration of protons from thin foils irradiated by hollow high-intensity laser beams in the regime of target normal sheath acceleration (TNSA) is reported for the first time. The use of hollow beams aims at reducing the initial emission solid angle of the TNSA source, due to a flattening of the electron sheath at the target rear side. The experiments were conducted at the PHELIX laser facility at the GSI Helmholtzzentrum für Schwerionenforschung GmbH with laser intensities in the range from 10 18  W cm −2 to 10 20  W cm −2 . We observed an average reduction of the half opening angle by (3.07±0.42)° or (13.2±2.0)% when the targets have a thickness between 12 μm and 14 μm. In addition, the highest proton energies were achieved with the hollow laser beam in comparison to the typical Gaussian focal spot

Laser-driven ion acceleration with hollow laser beams

Energy Technology Data Exchange (ETDEWEB)

Brabetz, C., E-mail: c.brabetz@gsi.de; Kester, O. [Goethe-Universität Frankfurt am Main, 60323 Frankfurt (Germany); GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Busold, S.; Bagnoud, V. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany); Helmholtz-Institut Jena, 07743 Jena (Germany); Cowan, T. [Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden (Germany); Technische Universität Dresden, 01069 Dresden (Germany); Deppert, O.; Jahn, D.; Roth, M. [Technische Universität Darmstadt, 64277 Darmstadt (Germany); Schumacher, D. [GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany)

2015-01-15

The laser-driven acceleration of protons from thin foils irradiated by hollow high-intensity laser beams in the regime of target normal sheath acceleration (TNSA) is reported for the first time. The use of hollow beams aims at reducing the initial emission solid angle of the TNSA source, due to a flattening of the electron sheath at the target rear side. The experiments were conducted at the PHELIX laser facility at the GSI Helmholtzzentrum für Schwerionenforschung GmbH with laser intensities in the range from 10{sup 18} W cm{sup −2} to 10{sup 20} W cm{sup −2}. We observed an average reduction of the half opening angle by (3.07±0.42)° or (13.2±2.0)% when the targets have a thickness between 12 μm and 14 μm. In addition, the highest proton energies were achieved with the hollow laser beam in comparison to the typical Gaussian focal spot.

Laser-induced damage in optical materials

CERN Document Server

Ristau, Detlev

2014-01-01

Dedicated to users and developers of high-powered systems, Laser-Induced Damage in Optical Materials focuses on the research field of laser-induced damage and explores the significant and steady growth of applications for high-power lasers in the academic, industrial, and military arenas. Written by renowned experts in the field, this book concentrates on the major topics of laser-induced damage in optical materials and most specifically addresses research in laser damage that occurs in the bulk and on the surface or the coating of optical components. It considers key issues in the field of hi

Semiconductor lasers driven by self-sustained chaotic electronic oscillators and applications to optical chaos cryptography.

Science.gov (United States)

Kingni, Sifeu Takougang; Mbé, Jimmi Hervé Talla; Woafo, Paul

2012-09-01

In this work, we numerically study the dynamics of vertical cavity surface emitting laser (VCSEL) firstly when it is driven by Chua's oscillator, secondly in case where it is driven by a broad frequency spectral bandwidth chaotic oscillator developed by Nana et al. [Commun. Nonlinear Sci. Numer. Simul. 14, 2266 (2009)]. We demonstrated that the VCSEL generated robust chaotic dynamics compared to the ones found in VCSEL subject to a sinusoidally modulated current and therefore it is more suitable for chaos encryption techniques. The synchronization characteristics and the communication performances of unidirectional coupled VCSEL driven by the broad frequency spectral bandwidth chaotic oscillators are investigated numerically. The results show that high-quality synchronization and transmission of messages can be realized for suitable system parameters. Chaos shift keying method is successfully applied to encrypt a message at a high bitrate.

A laser-driven source of polarized hydrogen and deuterium

International Nuclear Information System (INIS)

Young, L.; Holt, R.J.; Gilman, R.A.; Kowalczyk, R.; Coulter, K.

1989-01-01

A novel laser-driven polarized source of hydrogen and deuterium which operates on the principle of spin-exchange optical pumping is being developed. This source is designed to operate as an internal target in an electron storage ring for fundamental studies of spin-dependent structure of nuclei. It has the potential to exceed the flux from existing conventional sources (3 times 10 16/ s) by an order of magnitude. Currently, the source delivers hydrogen at a flux of 8 times 10 16 atoms/s with an atomic polarization of 24% and deuterium at 6 times 10 16 atoms/s with a polarization of 29%. Technical obstacles which have been overcome, with varying degrees of success are complete Doppler-coverage in the optical-pumping stage without the use of a buffer gas, wall-induced depolarization and radiation-trapping. Future improvements should allow achievement of the design goals of 4 times 10 17 atoms/s with a polarization of 50%. 8 refs., 2 figs

Characterization of the ELIMED Permanent Magnets Quadrupole system prototype with laser-driven proton beams

Science.gov (United States)

Schillaci, F.; Pommarel, L.; Romano, F.; Cuttone, G.; Costa, M.; Giove, D.; Maggiore, M.; Russo, A. D.; Scuderi, V.; Malka, V.; Vauzour, B.; Flacco, A.; Cirrone, G. A. P.

2016-07-01

Laser-based accelerators are gaining interest in recent years as an alternative to conventional machines [1]. In the actual ion acceleration scheme, energy and angular spread of the laser-driven beams are the main limiting factors for beam applications and different solutions for dedicated beam-transport lines have been proposed [2,3]. In this context a system of Permanent Magnet Quadrupoles (PMQs) has been realized [2] by INFN-LNS (Laboratori Nazionali del Sud of the Instituto Nazionale di Fisica Nucleare) researchers, in collaboration with SIGMAPHI company in France, to be used as a collection and pre-selection system for laser driven proton beams. This system is meant to be a prototype to a more performing one [3] to be installed at ELI-Beamlines for the collection of ions. The final system is designed for protons and carbons up to 60 MeV/u. In order to validate the design and the performances of this large bore, compact, high gradient magnetic system prototype an experimental campaign have been carried out, in collaboration with the group of the SAPHIR experimental facility at LOA (Laboratoire d'Optique Appliquée) in Paris using a 200 TW Ti:Sapphire laser system. During this campaign a deep study of the quadrupole system optics has been performed, comparing the results with the simulation codes used to determine the setup of the PMQ system and to track protons with realistic TNSA-like divergence and spectrum. Experimental and simulation results are good agreement, demonstrating the possibility to have a good control on the magnet optics. The procedure used during the experimental campaign and the most relevant results are reported here.

A study of optical design and optimization of laser optics

Science.gov (United States)

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

2013-09-01

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

Optical improvement for laser material processing

Energy Technology Data Exchange (ETDEWEB)

Bosman, J.; De Keijzer, M.A.; De Kok, C.J.G.M. [ECN Engineering and Services, Petten (Netherlands); Molenaar, R.; Kettelarij, H.

2010-05-15

The use of laser technology enables flexibility and new concepts for example solar cell production but also optical moulds. The reason why laser technology is used in these cases is not the laser system itself but the ability to tailor this type of energy to the demands of the production processes. To ensure the full potential of the laser technology it can be improved by adding optical elements like polarizer, cameras, lenses and sensors. Two of these extra optical elements are presented here. First laser pulse energy attenuation. This is used to increase the controllability of laser processes. And second a new camera optic that enables integrated alignment with respect to features on the product. This last option enables marking on existing features and automated compensation of scanner drift. These camera systems can be used for micro welding of polymers and repair of existing markings in moulds.

Laser-based terahertz-field-driven streak camera for the temporal characterization of ultrashort processes

Energy Technology Data Exchange (ETDEWEB)

Schuette, Bernd

2011-09-15

In this work, a novel laser-based terahertz-field-driven streak camera is presented. It allows for a pulse length characterization of femtosecond (fs) extreme ultraviolet (XUV) pulses by a cross-correlation with terahertz (THz) pulses generated with a Ti:sapphire laser. The XUV pulses are emitted by a source of high-order harmonic generation (HHG) in which an intense near-infrared (NIR) fs laser pulse is focused into a gaseous medium. The design and characterization of a high-intensity THz source needed for the streak camera is also part of this thesis. The source is based on optical rectification of the same NIR laser pulse in a lithium niobate crystal. For this purpose, the pulse front of the NIR beam is tilted via a diffraction grating to achieve velocity matching between NIR and THz beams within the crystal. For the temporal characterization of the XUV pulses, both HHG and THz beams are focused onto a gas target. The harmonic radiation creates photoelectron wavepackets which are then accelerated by the THz field depending on its phase at the time of ionization. This principle adopted from a conventional streak camera and now widely used in attosecond metrology. The streak camera presented here is an advancement of a terahertz-field-driven streak camera implemented at the Free Electron Laser in Hamburg (FLASH). The advantages of the laser-based streak camera lie in its compactness, cost efficiency and accessibility, while providing the same good quality of measurements as obtained at FLASH. In addition, its flexibility allows for a systematic investigation of streaked Auger spectra which is presented in this thesis. With its fs time resolution, the terahertz-field-driven streak camera thereby bridges the gap between attosecond and conventional cameras. (orig.)

Laser-based terahertz-field-driven streak camera for the temporal characterization of ultrashort processes

International Nuclear Information System (INIS)

Schuette, Bernd

2011-09-01

In this work, a novel laser-based terahertz-field-driven streak camera is presented. It allows for a pulse length characterization of femtosecond (fs) extreme ultraviolet (XUV) pulses by a cross-correlation with terahertz (THz) pulses generated with a Ti:sapphire laser. The XUV pulses are emitted by a source of high-order harmonic generation (HHG) in which an intense near-infrared (NIR) fs laser pulse is focused into a gaseous medium. The design and characterization of a high-intensity THz source needed for the streak camera is also part of this thesis. The source is based on optical rectification of the same NIR laser pulse in a lithium niobate crystal. For this purpose, the pulse front of the NIR beam is tilted via a diffraction grating to achieve velocity matching between NIR and THz beams within the crystal. For the temporal characterization of the XUV pulses, both HHG and THz beams are focused onto a gas target. The harmonic radiation creates photoelectron wavepackets which are then accelerated by the THz field depending on its phase at the time of ionization. This principle adopted from a conventional streak camera and now widely used in attosecond metrology. The streak camera presented here is an advancement of a terahertz-field-driven streak camera implemented at the Free Electron Laser in Hamburg (FLASH). The advantages of the laser-based streak camera lie in its compactness, cost efficiency and accessibility, while providing the same good quality of measurements as obtained at FLASH. In addition, its flexibility allows for a systematic investigation of streaked Auger spectra which is presented in this thesis. With its fs time resolution, the terahertz-field-driven streak camera thereby bridges the gap between attosecond and conventional cameras. (orig.)

Present status of laser driven fusion--fission energy systems

International Nuclear Information System (INIS)

Maniscalco, J.A.; Hansen, L.F.

1978-01-01

The potential of laser fusion driven hybrids to produce fissile fuel and/or electricity has been investigated in the laser program at the Lawrence Livermore Laboratory (LLL) for several years. Our earlier studies used neutronic methods of analysis to estimate hybrid performance. The results were encouraging, but it was apparent that a more accurate assessment of the hybrid's potential would require studies which treat the engineering, environmental, and economic issues as well as the neutronic aspects. More recently, we have collaborated with Bechtel and Westinghouse Corporations in two engineering design studies of laser fusion driven hybrid power plants. With Bechtel, we have been engaged in a joint effort to design a laser fusion driven hybrid which emphasizes fissile fuel production while the primary objective of our joint effort with Westinghouse has been to design a hybrid which emphasizes power production. The hybrid designs which have resulted from these two studies are briefly described and analyzed by considering their most important operational parameters

Optical double-locked semiconductor lasers

Science.gov (United States)

AlMulla, Mohammad

2018-06-01

Self-sustained period-one (P1) nonlinear dynamics of a semiconductor laser are investigated when both optical injection and modulation are applied for stable microwave frequency generation. Locking the P1 oscillation through modulation on the bias current, injection strength, or detuning frequency stabilizes the P1 oscillation. Through the phase noise variance, the different modulation types are compared. It is demonstrated that locking the P1 oscillation through optical modulation on the output of the master laser outperforms bias-current modulation of the slave laser. Master laser modulation shows wider P1-oscillation locking range and lower phase noise variance. The locking characteristics of the P1 oscillation also depend on the operating conditions of the optical injection system

Investigation toward laser driven IFE (inertial fusion energy) power plant

International Nuclear Information System (INIS)

Nakai, S.; Kozaki, Y.; Izawa, Y.; Yamanaka, M.; Kanabe, T.; Kato, Y.; Norimatsu, T.; Nagai, K.; Nakatsuka, M.; Jitsuno, T.; Yamanaka, T.

2000-01-01

Based on the conceptual design of Laser Driven IFE Power Plant, the technical and physical issues have been examined. R and D on key issues which affect the feasibility of power plant has been performed taking into account the collaboration in the field of laser driver, fuel pellet, reaction chamber and system design. The coordination and collaboration organization of reactor technology experts in Japan on Laser Driven IFE Power Plant are reviewed. (authors)

Springer handbook of lasers and optics

CERN Document Server

2012-01-01

The Springer Handbook of Lasers and Optics provides fast, up-to-date, comprehensive and authoritative coverage of the wide fields of optics and lasers. It is written for daily use in the office or laboratory and offers explanatory text, data, and references needed for anyone working with lasers and optical instruments. This second edition features numerous updates and additions. Especially four new chapters on Fiber Optics, Integrated Optics, Frequency Combs, and Interferometry reflect the major changes. In addition, chapters Optical Materials and Their Properties, Optical Detectors, Nanooptics, and Optics far Beyond the Diffraction Limit have been thoroughly revised and updated. The now 25 chapters are grouped into four parts which cover basic principles and materials, fabrication and properties of optical components, coherent and incoherent light sources, and, finally, selected applications and special fields such as terahertz photonics, x-ray optics and holography. Each chapter is authored by respected exp...

Optical engineering for high power laser applications

International Nuclear Information System (INIS)

Novaro, M.

1993-01-01

Laser facilities for Inertial Confinement Fusion (I.C.F.) experiments require laser and X ray optics able to withstand short pulse conditions. After a brief recall of high power laser system arrangements and of the characteristics of their optics, the authors will present some X ray optical developments

Laser-driven particle and photon beams and some applications

International Nuclear Information System (INIS)

Ledingham, K W D; Galster, W

2010-01-01

Outstanding progress has been made in high-power laser technology in the last 10 years with laser powers reaching petawatt (PW) values. At present, there are 15 PW lasers built or being built around the world and plans are afoot for new, even higher power, lasers reaching values of exawatt (EW) or even zetawatt (ZW) powers. Petawatt lasers generate electric fields of 10 12 V m -1 with a large fraction of the total pulse energy being converted to relativistic electrons with energies reaching in excess of 1 GeV. In turn these electrons result in the generation of beams of protons, heavy ions, neutrons and high-energy photons. These laser-driven particle beams have encouraged many to think of carrying out experiments normally associated with conventional nuclear accelerators and reactors. To this end a number of introductory articles have been written under a trial name 'Laser Nuclear Physics' (Ledingham and Norreys 1999 Contemp. Phys. 40 367, Ledingham et al 2002 Europhys. News. 33 120, Ledingham et al 2003 Science 300 1107, Takabe et al 2001 J. Plasma Fusion Res. 77 1094). However, even greater strides have been made in the last 3 or 4 years in laser technology and it is timely to reassess the potential of laser-driven particle and photon beams. It must be acknowledged right from the outset that to date laser-driven particle beams have yet to compete favourably with conventional nuclear accelerator-generated beams in any way and so this is not a paper comparing laser and conventional accelerators. However, occasionally throughout the paper as a reality check, it will be mentioned what conventional nuclear accelerators can do.

Laser-driven particle and photon beams and some applications

Energy Technology Data Exchange (ETDEWEB)

Ledingham, K W D; Galster, W, E-mail: K.Ledingham@phys.strath.ac.u [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

2010-04-15

Outstanding progress has been made in high-power laser technology in the last 10 years with laser powers reaching petawatt (PW) values. At present, there are 15 PW lasers built or being built around the world and plans are afoot for new, even higher power, lasers reaching values of exawatt (EW) or even zetawatt (ZW) powers. Petawatt lasers generate electric fields of 10{sup 12} V m{sup -1} with a large fraction of the total pulse energy being converted to relativistic electrons with energies reaching in excess of 1 GeV. In turn these electrons result in the generation of beams of protons, heavy ions, neutrons and high-energy photons. These laser-driven particle beams have encouraged many to think of carrying out experiments normally associated with conventional nuclear accelerators and reactors. To this end a number of introductory articles have been written under a trial name 'Laser Nuclear Physics' (Ledingham and Norreys 1999 Contemp. Phys. 40 367, Ledingham et al 2002 Europhys. News. 33 120, Ledingham et al 2003 Science 300 1107, Takabe et al 2001 J. Plasma Fusion Res. 77 1094). However, even greater strides have been made in the last 3 or 4 years in laser technology and it is timely to reassess the potential of laser-driven particle and photon beams. It must be acknowledged right from the outset that to date laser-driven particle beams have yet to compete favourably with conventional nuclear accelerator-generated beams in any way and so this is not a paper comparing laser and conventional accelerators. However, occasionally throughout the paper as a reality check, it will be mentioned what conventional nuclear accelerators can do.

High-Mach number, laser-driven magnetized collisionless shocks

International Nuclear Information System (INIS)

Schaeffer, Derek B.; Fox, W.; Haberberger, D.; Fiksel, G.; Bhattacharjee, A.

2017-01-01

Collisionless shocks are ubiquitous in space and astrophysical systems, and the class of supercritical shocks is of particular importance due to their role in accelerating particles to high energies. While these shocks have been traditionally studied by spacecraft and remote sensing observations, laboratory experiments can provide reproducible and multi-dimensional datasets that provide complementary understanding of the underlying microphysics. We present experiments undertaken on the OMEGA and OMEGA EP laser facilities that show the formation and evolution of high-Mach number collisionless shocks created through the interaction of a laser-driven magnetic piston and magnetized ambient plasma. Through time-resolved, 2-D imaging we observe large density and magnetic compressions that propagate at super-Alfvenic speeds and that occur over ion kinetic length scales. Electron density and temperature of the initial ambient plasma are characterized using optical Thomson scattering. Measurements of the piston laser-plasma are modeled with 2-D radiation-hydrodynamic simulations, which are used to initialize 2-D particle-in-cell simulations of the interaction between the piston and ambient plasmas. The numerical results show the formation of collisionless shocks, including the separate dynamics of the carbon and hydrogen ions that constitute the ambient plasma and their effect on the shock structure. Furthermore, the simulations also show the shock separating from the piston, which we observe in the data at late experimental times.

Photonic laser-driven accelerator for GALAXIE

Energy Technology Data Exchange (ETDEWEB)

Naranjo, B.; Ho, M.; Hoang, P.; Putterman, S.; Valloni, A.; Rosenzweig, J. B. [UCLA Dept. of Physics and Astronomy Los Angeles, CA 90095-1547 (United States)

2012-12-21

We report on the design and development of an all-dielectric laser-driven accelerator to be used in the GALAXIE (GV-per-meter Acce Lerator And X-ray-source Integrated Experiment) project's compact free-electron laser. The approach of our working design is to construct eigenmodes, borrowing from the field of photonics, which yield the appropriate, highly demanding dynamics in a high-field, short wavelength accelerator. Topics discussed include transverse focusing, power coupling, bunching, and fabrication.

Optical simulations of laser focusing for optimization of laser betatron

Czech Academy of Sciences Publication Activity Database

Stanke, Ladislav; Thakur, Anita; Šmíd, Michal; Gu, Yanjun; Falk, Kateřina

2017-01-01

Roč. 12, May (2017), 1-14, č. článku P05004. ISSN 1748-0221 R&D Projects: GA MŠk EF15_008/0000162; GA MŠk LQ1606 Grant - others:ELI Beamlines(XE) CZ.02.1.01/0.0/0.0/15_008/0000162 Institutional support: RVO:68378271 Keywords : matter * accelerator modelling and simulations * multi-particle dynamics * single-particle dynamics * Beam Optics Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 1.220, year: 2016

Laser driven detonation waves above a solid target

International Nuclear Information System (INIS)

Emmony, D.C.

1975-01-01

The interaction of a TEA CO 2 laser pulse with a carbon target in an argon atmosphere (p approximately mmHg) is shown to produce a double detonation wave system. The laser driven detonation wave becomes the most important as the gas pressure is increased. Calculation of the energy in the detonation waves is in good agreement with the incident laser energy at different times during the main laser pulse and the long tail. The observation of the incident laser detonation wave accounts for the anomalous energies reported previously. (Auth.)

Laser-driven nuclear-polarized hydrogen internal gas target

International Nuclear Information System (INIS)

Seely, J.; Crawford, C.; Clasie, B.; Xu, W.; Dutta, D.; Gao, H.

2006-01-01

We report the performance of a laser-driven polarized internal hydrogen gas target (LDT) in a configuration similar to that used in scattering experiments. This target used the technique of spin-exchange optical pumping to produce nuclear spin polarized hydrogen gas that was fed into a cylindrical storage (target) cell. We present in this paper the performance of the target, methods that were tried to improve the figure-of-merit (FOM) of the target, and a Monte Carlo simulation of spin-exchange optical pumping. The dimensions of the apparatus were optimized using the simulation and the experimental results were in good agreement with the results from the simulation. The best experimental result achieved was at a hydrogen flow rate of 1.1x10 18 atoms/s, where the sample beam exiting the storage cell had 58.2% degree of dissociation and 50.5% polarization. Based on this measurement, the atomic fraction in the storage cell was 49.6% and the density averaged nuclear polarization was 25.0%. This represents the highest FOM for hydrogen from an LDT and is higher than the best FOM reported by atomic beam sources that used storage cells

Free-electron laser driven by the LBNL laser-plasma accelerator

International Nuclear Information System (INIS)

Schroeder, C.B.; Fawley, W.M.; Gruner, F.; Bakeman, M.; Nakamura, K.; Robinson, K.E.; Toth, Cs.; Esarey, E.; Leemans, W.P.

2008-01-01

A design of a compact free-electron laser (FEL), generating ultra-fast, high-peak flux, XUV pulses is presented. The FEL is driven by ahigh-current, 0.5 GeV electron beam from the Lawrence Berkeley National Laboratory (LBNL) laser-plasma accelerator, whose active acceleration length is only a few centimeters. The proposed ultra-fast source (∼10 fs) would be intrinsically temporally synchronized to the drive laser pulse, enabling pump-probe studies in ultra-fast science. Owing to the high current (>10 kA) of the laser-plasma-accelerated electron beams, saturated output fluxes are potentially greater than 10 13 photons/pulse. Devices based both on self-amplified spontaneous emission and high-harmonic generated input seeds, to reduce undulator length and fluctuations, are considered.

Laser driven white light source for BRDF measurement

DEFF Research Database (Denmark)

Amdemeskel, Mekbib Wubishet; Thorseth, Anders; Dam-Hansen, Carsten

2017-01-01

In this paper, we will present a setup with laser driven light source (LDLS) for measuring a 2D bidirectional reflectance distribution function (BRDF). We have carried out measurements to acquire the BRDF of different samples based on our setup: which consists of a new laser driven broadband light...... source (UV-VIS-NIR), spectroradiometer and sample holder stepper motor in a dark UV-protected environment. Here, we introduced a special kind of light source which has a bright, stable, broad spectral range and well collimated light output to give a very good angular resolution. The experimental results...

Use of a reflective semiconductor optical amplifier and dual-ring architecture design to produce a stable multi-wavelength fiber laser

International Nuclear Information System (INIS)

Yeh, Chien-Hung; Chow, Chi-Wai; Lu, Shao-Sheng

2014-01-01

In this work, we propose and demonstrate a multi-wavelength laser source produced by utilizing a C-band reflective semiconductor optical amplifier (RSOA) with a dual-ring fiber cavity. Here, the laser cavity consists of an RSOA, a 1 × 2 optical coupler, a 2 × 2 optical coupler and a polarization controller. As a result, thirteen to eighteen wavelengths around the L band could be generated simultaneously when the bias current of the C-band RSOA was driven at 30–70 mA. In addition, the output stabilities of the power and wavelength are also discussed. (paper)

Use of a reflective semiconductor optical amplifier and dual-ring architecture design to produce a stable multi-wavelength fiber laser

Science.gov (United States)

Yeh, Chien-Hung; Chow, Chi-Wai; Lu, Shao-Sheng

2014-05-01

In this work, we propose and demonstrate a multi-wavelength laser source produced by utilizing a C-band reflective semiconductor optical amplifier (RSOA) with a dual-ring fiber cavity. Here, the laser cavity consists of an RSOA, a 1 × 2 optical coupler, a 2 × 2 optical coupler and a polarization controller. As a result, thirteen to eighteen wavelengths around the L band could be generated simultaneously when the bias current of the C-band RSOA was driven at 30-70 mA. In addition, the output stabilities of the power and wavelength are also discussed.

Optical Axis Identification Technique for Free Space Optics Transmission

Directory of Open Access Journals (Sweden)

Yuki Tashiro

2017-07-01

Full Text Available This paper describes optical axis adjustment technique for an active free space optics transmission system. This system precisely controls the direction of a collimated thin laser beam using a motor driven laser emitting mechanism and positioning photodiodes. Before beginning laser beam feedback control, it is required to guide the laser beam within the range of the positioning photodiodes for initial laser beam alignment. This paper proposes an arrival position presumption method of laser beam traveling along the long distance from transmitter. A positioning sensor containing several photodiodes measures laser luminescence distribution, and analytically calculates the optical axis of laser beam according to the modified Gaussian beam optics based on four or five distributed local intensity of laser luminescence. Experiments are conducted to evaluate the accuracy of the presumption, and results reveal that the method is effective in leading the laser beam onto a distant receiver.

Adaptive optics and laser guide stars at Lick observatory

Energy Technology Data Exchange (ETDEWEB)

Brase, J.M. [Lawrence Livermore National Lab., CA (United States)

1994-11-15

For the past several years LLNL has been developing adaptive optics systems for correction of both atmospheric turbulence effects and thermal distortions in optics for high-power lasers. Our early work focused on adaptive optics for beam control in laser isotope separation and ground-based free electron lasers. We are currently developing innovative adaptive optics and laser systems for sodium laser guide star applications at the University of California`s Lick and Keck Observeratories. This talk will describe our adaptive optics technology and some of its applications in high-resolution imaging and beam control.

ELIMAIA: A Laser-Driven Ion Accelerator for Multidisciplinary Applications

Directory of Open Access Journals (Sweden)

Daniele Margarone

2018-04-01

Full Text Available The main direction proposed by the community of experts in the field of laser-driven ion acceleration is to improve particle beam features (maximum energy, charge, emittance, divergence, monochromaticity, shot-to-shot stability in order to demonstrate reliable and compact approaches to be used for multidisciplinary applications, thus, in principle, reducing the overall cost of a laser-based facility compared to a conventional accelerator one and, at the same time, demonstrating innovative and more effective sample irradiation geometries. The mission of the laser-driven ion target area at ELI-Beamlines (Extreme Light Infrastructure in Dolní Břežany, Czech Republic, called ELI Multidisciplinary Applications of laser-Ion Acceleration (ELIMAIA , is to provide stable, fully characterized and tuneable beams of particles accelerated by Petawatt-class lasers and to offer them to the user community for multidisciplinary applications. The ELIMAIA beamline has been designed and developed at the Institute of Physics of the Academy of Science of the Czech Republic (IoP-ASCR in Prague and at the National Laboratories of Southern Italy of the National Institute for Nuclear Physics (LNS-INFN in Catania (Italy. An international scientific network particularly interested in future applications of laser driven ions for hadrontherapy, ELI MEDical applications (ELIMED, has been established around the implementation of the ELIMAIA experimental system. The basic technology used for ELIMAIA research and development, along with envisioned parameters of such user beamline will be described and discussed.

Cost reduction study for the LANL KrF laser-driven LMF design

International Nuclear Information System (INIS)

1989-01-01

This report is in fulfillment of the deliverable requirements for the optical components portions of the LANL-KrF Laser-Driven LMF Design Cost Reduction Study. This report examines the future cost reductions that may accrue through the use of mass production, innovative manufacturing techniques, and new materials. Results are based on data collection and survey of optical component manufacturers, BDM experience, and existing cost models. These data provide a good representation of current methods and technologies from which future estimates can be made. From these data, a series of scaling relationships were developed to project future costs for a selected set of technologies. The scaling relationships are sensitive to cost driving parameters such as size and surface figure requirements as well as quantity requirements, production rate, materials, and manufacturing processes. In addition to the scaling relationships, descriptions of the selected processes were developed along with graphical representations of the processes. This report provides a useful tool in projecting the costs of advanced laser concepts at the component level of detail. A mix of the most diverse yet comparable technologies was chosen for this study. This yielded a useful, yet manageable number of variables to examine. The study has resulted in a first-order cost model which predicts the relative cost behavior of optical components within different variable constraints

Optics with an Atom Laser Beam

International Nuclear Information System (INIS)

Bloch, Immanuel; Koehl, Michael; Greiner, Markus; Haensch, Theodor W.; Esslinger, Tilman

2001-01-01

We report on the atom optical manipulation of an atom laser beam. Reflection, focusing, and its storage in a resonator are demonstrated. Precise and versatile mechanical control over an atom laser beam propagating in an inhomogeneous magnetic field is achieved by optically inducing spin flips between atomic ground states with different magnetic moment. The magnetic force acting on the atoms can thereby be effectively switched on and off. The surface of the atom optical element is determined by the resonance condition for the spin flip in the inhomogeneous magnetic field. More than 98% of the incident atom laser beam is reflected specularly

Evaluation of laser-driven ion energies for fusion fast-ignition research

Science.gov (United States)

Tosaki, S.; Yogo, A.; Koga, K.; Okamoto, K.; Shokita, S.; Morace, A.; Arikawa, Y.; Fujioka, S.; Nakai, M.; Shiraga, H.; Azechi, H.; Nishimura, H.

2017-10-01

We investigate laser-driven ion acceleration using kJ-class picosecond (ps) laser pulses as a fundamental study for ion-assisted fusion fast ignition, using a newly developed Thomson-parabola ion spectrometer (TPIS). The TPIS has a space- and weight-saving design, considering its use in an laser-irradiation chamber in which 12 beams of fuel implosion laser are incident, and, at the same time, demonstrates sufficient performance with its detectable range and resolution of the ion energy required for fast-ignition research. As a fundamental study on laser-ion acceleration using a ps pulse laser, we show proton acceleration up to 40 MeV at 1 × 10^{19} W cm^{-2}. The energy conversion efficiency from the incident laser into protons higher than 6 MeV is 4.6%, which encourages the realization of fusion fast ignition by laser-driven ions.

Laser-driven particle acceleration towards radiobiology and medicine

CERN Document Server

2016-01-01

This book deals with the new method of laser-driven acceleration for application to radiation biophysics and medicine. It provides multidisciplinary contributions from world leading scientist in order to assess the state of the art of innovative tools for radiation biology research and medical applications of ionizing radiation. The book contains insightful contributions on highly topical aspects of spatio-temporal radiation biophysics, evolving over several orders of magnitude, typically from femtosecond and sub-micrometer scales. Particular attention is devoted to the emerging technology of laser-driven particle accelerators and their applicatio to spatio-temporal radiation biology and medical physics, customization of non-conventional and selective radiotherapy and optimized radioprotection protocols.

Phase locking of optically coupled lasers

International Nuclear Information System (INIS)

Glova, A F

2003-01-01

A review of studies of the properties of radiation from optically coupled lasers is presented. The methods for phase locking the fields in optically coupled lasers of different types are considered and the methods for supermode selection and correction of the radiation pattern are discussed. (review)

Laser systems with diamond optical elements

International Nuclear Information System (INIS)

Seitz, J.R.

1975-01-01

High power laser systems with optical elements of diamond having a thermal conductivity of at least 10 W/cm. 0 K at 300 0 K and an optical absorption at the laser beam wavelength of no more than 10 to 20 percent are described. (U.S.)

LASNEX simulations of the classical and laser-driven Rayleigh-Taylor instability

International Nuclear Information System (INIS)

Mikaelian, K.O.

1990-01-01

We present the results of two-dimensional LASNEX simulations of the classical and laser-driven Rayleigh-Taylor instability. Our growth rates and eigenmodes for classical two- and three-fluid problems agree closely with the exact analytic expressions. We illustrate in several examples how perturbations feed through from one interface to another. For targets driven by a 1/4-μm laser at I=2x10 14 W/cm 2 our growth rates are 40--80 % of the classical case rates for wavelengths between 5 and 100 μm. We find that radiation transport has a stabilizing effect on the Rayleigh-Taylor instability, particularly at high intensities. A brief comparison with a laser-driven experiment is also presented

Handbook of optical and laser scanning

CERN Document Server

Marshall, Gerald F

2011-01-01

From its initial publication titled Laser Beam Scanning in 1985 to Handbook of Optical and Laser Scanning, now in its second edition, this reference has kept professionals and students at the forefront of optical scanning technology. Carefully and meticulously updated in each iteration, the book continues to be the most comprehensive scanning resource on the market. It examines the breadth and depth of subtopics in the field from a variety of perspectives. The Second Edition covers: Technologies such as piezoelectric devices Applications of laser scanning such as Ladar (laser radar) Underwater

Supersonic Ionization Wave Driven by Radiation Transport in a Short-Pulse Laser-Produced Plasma

International Nuclear Information System (INIS)

Ditmire, T.; Gumbrell, E.T.; Smith, R.A.; Mountford, L.; Hutchinson, M.H.

1996-01-01

Through the use of an ultrashort (2ps) optical probe, we have time resolved the propagation of an ionization wave into solid fused silica. This ionization wave results when a plasma is created by the intense irradiation of a solid target with a 2ps laser pulse. We find that the velocity of the ionization wave is consistent with radiation driven thermal transport, exceeding the velocity expected from simple electron thermal conduction by nearly an order of magnitude. copyright 1996 The American Physical Society

Laser optical pumping of sodium and lithium atom beams

International Nuclear Information System (INIS)

Cusma, J.T.

1983-01-01

The method of optical pumping with a continuous wave dye laser has been used to produce beams of polarized 23 Na atoms and polarized 6 Li atoms. Optical pumping of a 23 Na atom beam using either a multimode dye laser or a single frequency dye laser with a double passed acousto-optic modulator results in electron spin polarizations of 0.70-0.90 and nuclear spin polarizations of 0.75-0.90. Optical pumping of a 6 Li atom beam using a single frequency dye laser either with an acousto-optic modulator or with Doppler shift pumping results in electron spin polarizations of 0.77-0.95 and nuclear spin polarizations greater than 0.90. The polarization of the atom beam is measured using either the laser induced fluorescence in an intermediate magnetic field or a 6-pole magnet to determine the occupation probabilities of the ground hyperfine sublevels following optical pumping. The results of the laser optical pumping experiments agree with the results of a rate equation analysis of the optical pumping process which predicts that nearly all atoms are transferred into a single sublevel for our values of laser intensity and interaction time. The use of laser optical pumping in a polarized ion source for nuclear scattering experiments is discussed. The laser optical pumping method provides a means of constructing an intense source of polarized Li and Na ions

Laser - driven high - energy ions and their application to inertial confinement fusion

International Nuclear Information System (INIS)

Borghesi, M.

2007-01-01

The acceleration of high-energy ion beams (up to several tens of MeV per nucleon) following the interaction of short and intense laser pulses with solid targets has been one of the most important results of recent laser-plasma research [1]. The acceleration is driven by relativistic electrons, which acquire energy directly from the laser pulse and set up extremely large (∼TV/m) space charge fields at the target interfaces. The properties of laser-driven ion beams (high brightness and laminarity, high-energy cut-off, ultrashort burst duration) distinguish them from lower energy ions accelerated in earlier experiments at moderate laser intensities, and compare favourably with those of 'conventional' accelerator beams. In view of these properties, laser-driven ion beams can be employed in a number of innovative applications in the scientific, technological and medical areas. We will discuss in particular aspects of interest to their application in an Inertial Confinement Fusion context. Laser-driven protons are indeed being considered as a possible trigger for Fast Ignition of a precompressed fuel.[2] Recent results relating to the optimization of beam energy and focusing will be presented. These include the use of laser-driven impulsive fields for proton beam collimation and focusing [3], and the investigation of acceleration in presence of finite-scale plasma gradient. Proposed target developments enabling proton production at high repetition rate will also be discussed. Another important area of application of proton beams is diagnostic use in a particle probing arrangement for detection of density non-homogeneities [4] and electric/magnetic fields [5]. We will discuss the use of laser-driven proton beams for the diagnosis of magnetic and electric fields in planar and hohlraum targets and for the detection of fields associated to relativistic electron propagation through dense matter, an issue of high relevance for electron driven Fast Ignition. [1] M

Improving fiber-optic laser beam delivery by incorporating GRADIUM optics

International Nuclear Information System (INIS)

Hunter, B.V.; Leong, K.H.

1997-01-01

The performance of a fiber-optic laser beam delivery system strongly depends on the fiber and the optics used to image the fiber face on the workpiece. We have compared off-the-shelf homogenous (BK7) and GRADIUM (axial-gradient) singlets to determine what improvement the GRADIUM offers in practice to the typical laser user. The realized benefit for this application, although significant, is much smaller than would be realized by a conventional imaging application. The figure of merit for laser-based materials processing is the 86% energy-enclosure radius, which is not directly supported by commerical ray-tracing software. Therefore empirical rules of thumb are presented to understand when GRADIUM (or any other well-corrected optics) will yield meaningful improvement to the beam delivery system. copyright 1997 Optical Society of America

International Conference on Laser Physics and Quantum Optics

CERN Document Server

Xie, Shengwu; Zhu, Shi-Yao; Scully, Marlan

2000-01-01

Since the advent of the laser about 40 years ago, the field of laser physics and quantum optics have evolved into a major discipline. The early studies included the optical coherence theory and the semiclassical and quantum mechanical theories of the laser. More recently many new and interesting effects have been predicted. These include the role of coherent atomic effects in lasing without inversion and electromagnetically induced transparency, atom optics, laser cooling and trapping, teleportation, the single-atom micromaser and its role in quantum measurement theory, to name a few. The International Conference on Laser Physics and Quantum Optics was held in Shanghai from August 25 to August 28, 1999, to discuss these and many other exciting developments in laser physics and quantum optics. The international character of the conference was manifested by the fact that scientists from over 13 countries participated and lectured at the conference. There were four keynote lectures delivered by Nobel laureate Wi...

Editorial: Focus on Laser- and Beam-Driven Plasma Accelerators

Science.gov (United States)

Joshi, Chan; Malka, Victor

2010-04-01

, S Mangles, L O Silva, R Fonseca and P A Norreys Electro-optic shocks from blowout laser wakefields D F Gordon, A Ting, M H Helle, D Kaganovich and B Hafizi Onset of self-steepening of intense laser pulses in plasmas J Vieira, F Fiúza, L O Silva, M Tzoufras and W B Mori Analysis of laser wakefield dynamics in capillary tubes N E Andreev, K Cassou, F Wojda, G Genoud, M Burza, O Lundh, A Persson, B Cros, V E Fortov and C-G Wahlstrom Characterization of the beam loading effects in a laser plasma accelerator C Rechatin, J Faure, X Davoine, O Lundh, J Lim, A Ben-Ismaïl, F Burgy, A Tafzi, A Lifschitz, E Lefebvre and V Malka Energy gain scaling with plasma length and density in the plasma wakefield accelerator P Muggli, I Blumenfeld, C E Clayton, F J Decker, M J Hogan, C Huang, R Ischebeck, R H Iverson, C Joshi, T Katsouleas, N Kirby, W Lu, K A Marsh, W B Mori, E Oz, R H Siemann, D R Walz and M Zhou Generation of tens of GeV quasi-monoenergetic proton beams from a moving double layer formed by ultraintense lasers at intensity 1021-1023Wcm-2 Lu-Le Yu, Han Xu, Wei-Min Wang, Zheng-Ming Sheng, Bai-Fei Shen, Wei Yu and Jie Zhang Carbon ion acceleration from thin foil targets irradiated by ultrahigh-contrast, ultraintense laser pulses D C Carroll, O Tresca, R Prasad, L Romagnani, P S Foster, P Gallegos, S Ter-Avetisyan, J S Green, M J V Streeter, N Dover, C A J Palmer, C M Brenner, F H Cameron, K E Quinn, J Schreiber, A P L Robinson, T Baeva, M N Quinn, X H Yuan, Z Najmudin, M Zepf, D Neely, M Borghesi and P McKenna Numerical modelling of a 10-cm-long multi-GeV laser wakefield accelerator driven by a self-guided petawatt pulse S Y Kalmykov, S A Yi, A Beck, A F Lifschitz, X Davoine, E Lefebvre, A Pukhov, V Khudik, G Shvets, S A Reed, P Dong, X Wang, D Du, S Bedacht, R Zgadzaj, W Henderson, A Bernstein, G Dyer, M Martinez, E Gaul, T Ditmire and M C Downer Effects of laser prepulses on laser-induced proton generation D Batani, R Jafer, M Veltcheva, R Dezulian, O Lundh, F Lindau, A

Intense laser driven collision-less shock and ion acceleration in magnetized plasmas

Science.gov (United States)

Mima, K.; Jia, Q.; Cai, H. B.; Taguchi, T.; Nagatomo, H.; Sanz, J. R.; Honrubia, J.

2016-05-01

The generation of strong magnetic field with a laser driven coil has been demonstrated by many experiments. It is applicable to the magnetized fast ignition (MFI), the collision-less shock in the astrophysics and the ion shock acceleration. In this paper, the longitudinal magnetic field effect on the shock wave driven by the radiation pressure of an intense short pulse laser is investigated by theory and simulations. The transition of a laminar shock (electro static shock) to the turbulent shock (electromagnetic shock) occurs, when the external magnetic field is applied in near relativistic cut-off density plasmas. This transition leads to the enhancement of conversion of the laser energy into high energy ions. The enhancement of the conversion efficiency is important for the ion driven fast ignition and the laser driven neutron source. It is found that the total number of ions reflected by the shock increases by six time when the magnetic field is applied.

A Large Aperture, High Energy Laser System for Optics and Optical Component Testing

International Nuclear Information System (INIS)

Nostrand, M.C.; Weiland, T.L.; Luthi, R.L.; Vickers, J.L.; Sell, W.D.; Stanley, J.A.; Honig, J.; Auerbach, J.; Hackel, R.P.; Wegner, P.J.

2003-01-01

A large aperture, kJ-class, multi-wavelength Nd-glass laser system has been constructed at Lawrence Livermore National Lab which has unique capabilities for studying a wide variety of optical phenomena. The master-oscillator, power-amplifier (MOPA) configuration of this ''Optical Sciences Laser'' (OSL) produces 1053 nm radiation with shaped pulse lengths which are variable from 0.1-100 ns. The output can be frequency doubled or tripled with high conversion efficiency with a resultant 100 cm 2 high quality output beam. This facility can accommodate prototype hardware for large-scale inertial confinement fusion lasers allowing for investigation of integrated system issues such as optical lifetime at high fluence, optics contamination, compatibility of non-optical materials, and laser diagnostics

Characterisation of electron beams from laser-driven particle accelerators

Energy Technology Data Exchange (ETDEWEB)

Brunetti, E.; Manahan, G. G.; Shanks, R. P.; Islam, M. R.; Ersfeld, B.; Anania, M. P.; Cipiccia, S.; Issac, R. C.; Vieux, G.; Welsh, G. H.; Wiggins, S. M.; Jaroszynski, D. A. [Physics Department, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

2012-12-21

The development, understanding and application of laser-driven particle accelerators require accurate measurements of the beam properties, in particular emittance, energy spread and bunch length. Here we report measurements and simulations showing that laser wakefield accelerators can produce beams of quality comparable to conventional linear accelerators.

Lasing by driven atoms-cavity system in collective strong coupling regime.

Science.gov (United States)

Sawant, Rahul; Rangwala, S A

2017-09-12

The interaction of laser cooled atoms with resonant light is determined by the natural linewidth of the excited state. An optical cavity is another optically resonant system where the loss from the cavity determines the resonant optical response of the system. The near resonant combination of an optical Fabry-Pérot cavity with laser cooled and trapped atoms couples two distinct optical resonators via light and has great potential for precision measurements and the creation of versatile quantum optics systems. Here we show how driven magneto-optically trapped atoms in collective strong coupling regime with the cavity leads to lasing at a frequency red detuned from the atomic transition. Lasing is demonstrated experimentally by the observation of a lasing threshold accompanied by polarization and spatial mode purity, and line-narrowing in the outcoupled light. Spontaneous emission into the cavity mode by the driven atoms stimulates lasing action, which is capable of operating as a continuous wave laser in steady state, without a seed laser. The system is modeled theoretically, and qualitative agreement with experimentally observed lasing is seen. Our result opens up a range of new measurement possibilities with this system.

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...

Dynamics of Laser-Driven Shock Waves in Solid Targets

Science.gov (United States)

Aglitskiy, Y.; Karasik, M.; Velikovich, A. L.; Serlin, V.; Weaver, J.; Schmitt, A. J.; Obenschain, S. P.; Grun, J.; Metzler, N.; Zalesak, S. T.; Gardner, J. H.; Oh, J.; Harding, E. C.

2009-11-01

Accurate shock timing is a key issue of both indirect- and direct-drive laser fusions. The experiments on the Nike laser at NRL presented here were made possible by improvements in the imaging capability of our monochromatic x-ray diagnostics based on Bragg reflection from spherically curved crystals. Side-on imaging implemented on Nike makes it possible to observe dynamics of the shock wave and ablation front in laser-driven solid targets. We can choose to observe a sequence of 2D images or a continuous time evolution of an image resolved in one spatial dimension. A sequence of 300 ps snapshots taken using vanadium backlighter at 5.2 keV reveals propagation of a shock wave in a solid plastic target. The shape of the shock wave reflects the intensity distribution in the Nike beam. The streak records with continuous time resolution show the x-t trajectory of a laser-driven shock wave in a 10% solid density DVB foam.

Electro-Optical Laser Technology. Curriculum Utilization. Final Report.

Science.gov (United States)

Nawn, John H.

This report describes a program to prepare students for employment as laser technicians and laser operators and to ensure that they have the necessary skills required by the industry. The objectives are to prepare a curriculum and syllabus for an associate degree program in Electro-Optical Laser Technology. The 2-year Electro-Optical Laser program…

Cost Effective, Scalable Optically Pumped Molecular Laser

National Research Council Canada - National Science Library

Nicholson, Jeff

2001-01-01

An optically pumped, For laser was demonstrated operating at 4.0 micrometers. This is the first demonstration of an HBr laser by direct optical pumping of the 0 right arrow 3 vibrational overtone band at 1.34 micrometers...

Laser-driven ultrafast antiproton beam

Science.gov (United States)

Li, Shun; Pei, Zhikun; Shen, Baifei; Xu, Jiancai; Zhang, Lingang; Zhang, Xiaomei; Xu, Tongjun; Yu, Yong; Bu, Zhigang

2018-02-01

Antiproton beam generation is investigated based on the ultra-intense femtosecond laser pulse by using two-dimensional particle-in-cell and Geant4 simulations. A high-flux proton beam with an energy of tens of GeV is generated in sequential radiation pressure and bubble regime and then shoots into a high-Z target for producing antiprotons. Both yield and energy of the antiproton beam increase almost linearly with the laser intensity. The generated antiproton beam has a short pulse duration of about 5 ps and its flux reaches 2 × 10 20 s - 1 at the laser intensity of 2.14 × 10 23 W / cm 2 . Compared to conventional methods, this new method based on the ultra-intense laser pulse is able to provide a compact, tunable, and ultrafast antiproton source, which is potentially useful for quark-gluon plasma study, all-optical antihydrogen generation, and so on.

Modeling of laser-driven hydrodynamics experiments

Science.gov (United States)

di Stefano, Carlos; Doss, Forrest; Rasmus, Alex; Flippo, Kirk; Desjardins, Tiffany; Merritt, Elizabeth; Kline, John; Hager, Jon; Bradley, Paul

2017-10-01

Correct interpretation of hydrodynamics experiments driven by a laser-produced shock depends strongly on an understanding of the time-dependent effect of the irradiation conditions on the flow. In this talk, we discuss the modeling of such experiments using the RAGE radiation-hydrodynamics code. The focus is an instability experiment consisting of a period of relatively-steady shock conditions in which the Richtmyer-Meshkov process dominates, followed by a period of decaying flow conditions, in which the dominant growth process changes to Rayleigh-Taylor instability. The use of a laser model is essential for capturing the transition. also University of Michigan.

Optical pumping of Rb by Ti:Sa laser and high-power laser diode

Czech Academy of Sciences Publication Activity Database

Buchta, Zdeněk; Rychnovský, Jan; Lazar, Josef

2006-01-01

Roč. 8, č. 1 (2006), s. 350-354 ISSN 1454-4164 R&D Projects: GA AV ČR IAA1065303; GA ČR GA102/04/2109 Institutional research plan: CEZ:AV0Z20650511 Keywords : optical pumping * Ti:Sa laser * laser diode * emission linewidth * spectroscopy * laser frequency stabilization Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.106, year: 2006

Detrimental Effect Elimination of Laser Frequency Instability in Brillouin Optical Time Domain Reflectometer by Using Self-Heterodyne Detection

Directory of Open Access Journals (Sweden)

Yongqian Li

2017-03-01

Full Text Available A useful method for eliminating the detrimental effect of laser frequency instability on Brillouin signals by employing the self-heterodyne detection of Rayleigh and Brillouin scattering is presented. From the analysis of Brillouin scattering spectra from fibers with different lengths measured by heterodyne detection, the maximum usable pulse width immune to laser frequency instability is obtained to be about 4 µs in a self-heterodyne detection Brillouin optical time domain reflectometer (BOTDR system using a broad-band laser with low frequency stability. Applying the self-heterodyne detection of Rayleigh and Brillouin scattering in BOTDR system, we successfully demonstrate that the detrimental effect of laser frequency instability on Brillouin signals can be eliminated effectively. Employing the broad-band laser modulated by a 130-ns wide pulse driven electro-optic modulator, the observed maximum errors in temperatures measured by the local heterodyne and self-heterodyne detection BOTDR systems are 7.9 °C and 1.2 °C, respectively.

Optical system for laser triggering of PBFA II

International Nuclear Information System (INIS)

Hamil, R.A.; Seamons, L.O.; Schanwald, L.P.; Gerber, R.A.

1985-01-01

The PBFA II laser triggering optical system consists of nearly 300 optical components. These optics must be sufficiently precise to preserve the laser beam quality, as well as to equally distribute the energy of the UV laser beam to the 36, 5.5 MV gas-filled switches at precisely the same instant. Both index variation and cleanliness of the air long the laser path must be controlled. The manual alignment system is capable of alignment to better than the acceptable error of 200 microradians (laser to switches). A technique has been devised to ease the alignment procedure by using a special high gain video camera and a tool alignment telescope to view retroreflective tape targets having optical brightness gains over white surfaces of 10/sup 3/. The camera is a charge-coupled detector intensified by a double microchannel plate having an optical gain of between 10/sup 4/ and 10/sup 5/

Weibel instability mediated collisionless shocks using intense laser-driven plasmas

Science.gov (United States)

Palaniyappan, Sasikumar; Fiuza, Federico; Huang, Chengkun; Gautier, Donald; Ma, Wenjun; Schreiber, Jorg; Raymer, Abel; Fernandez, Juan; Shimada, Tom; Johnson, Randall

2017-10-01

The origin of cosmic rays remains a long-standing challenge in astrophysics and continues to fascinate physicists. It is believed that ``collisionless shocks'' - where the particle Coulomb mean free path is much larger that the shock transition - are a dominant source of energetic cosmic rays. These shocks are ubiquitous in astrophysical environments such as gamma-ray bursts, supernova remnants, pulsar wind nebula and coronal mass ejections from the sun. A particular type of electromagnetic plasma instability known as Weibel instability is believed to be the dominant mechanism behind the formation of these collisionless shocks in the cosmos. The understanding of the microphysics behind collisionless shocks and their particle acceleration is tightly related with nonlinear basic plasma processes and remains a grand challenge. In this poster, we will present results from recent experiments at the LANL Trident laser facility studying collisionless shocks using intense ps laser (80J, 650 fs - peak intensity of 1020 W/cm2) driven near-critical plasmas using carbon nanotube foam targets. A second short pulse laser driven protons from few microns thick gold foil is used to radiograph the main laser-driven plasma. Work supported by the LDRD program at LANL.

Supersonic micro-jets and their application to few-cycle laser-driven electron acceleration

International Nuclear Information System (INIS)

Schmid, Karl

2009-01-01

This thesis covers the few-cycle laser-driven acceleration of electrons in a laser-generated plasma. The laser system employed in this work is a new development based on optical parametric chirped pulse amplification and is the only multi-TW few-cycle laser in the world. In the experiment, the laser beam is focused onto a supersonic helium gas jet which leads to the formation of a plasma channel. The laser pulse, having an intensity of 10 19 W/cm 2 propagates through the plasma with an electron density of 2 x 10 19 cm -3 and forms via a highly nonlinear interaction a strongly anharmonic plasma wave. The amplitude of the wave is so large that the wave breaks, thereby injecting electrons from the background plasma into the accelerating phase. The energy transfer from the laser pulse to the plasma is so strong that the maximum propagation distance is limited to the 100 m range. Therefore, gas jets specifically tuned to these requirements have to be employed. The properties of microscopic supersonic gas jets are thoroughly analyzed in this work. Based on numeric flow simulation, this study encompasses several extensive parameter studies that illuminate all relevant features of supersonic flows in microscopic gas nozzles. This allowed the optimized design of de Laval nozzles with exit diameters ranging from 150 μm to 3 mm. The employment of these nozzles in the experiment greatly improved the electron beam quality. After these optimizations, the laser-driven electron accelerator now yields monoenergetic electron pulses with energies up to 50 MeV and charges between one and ten pC. The electron beam has a typical divergence of 5 mrad and comprises an energy spectrum that is virtually free from low energetic background. The electron pulse duration could not yet be determined experimentally but simulations point towards values in the range of 1 fs. The acceleration gradient is estimated from simulation and experiment to be approximately 0.5 TV/m. The electron accelerator

Supersonic micro-jets and their application to few-cycle laser-driven electron acceleration

Energy Technology Data Exchange (ETDEWEB)

Schmid, Karl

2009-07-23

This thesis covers the few-cycle laser-driven acceleration of electrons in a laser-generated plasma. The laser system employed in this work is a new development based on optical parametric chirped pulse amplification and is the only multi-TW few-cycle laser in the world. In the experiment, the laser beam is focused onto a supersonic helium gas jet which leads to the formation of a plasma channel. The laser pulse, having an intensity of 10{sup 19} W/cm{sup 2} propagates through the plasma with an electron density of 2 x 10{sup 19} cm{sup -3} and forms via a highly nonlinear interaction a strongly anharmonic plasma wave. The amplitude of the wave is so large that the wave breaks, thereby injecting electrons from the background plasma into the accelerating phase. The energy transfer from the laser pulse to the plasma is so strong that the maximum propagation distance is limited to the 100 m range. Therefore, gas jets specifically tuned to these requirements have to be employed. The properties of microscopic supersonic gas jets are thoroughly analyzed in this work. Based on numeric flow simulation, this study encompasses several extensive parameter studies that illuminate all relevant features of supersonic flows in microscopic gas nozzles. This allowed the optimized design of de Laval nozzles with exit diameters ranging from 150 {mu}m to 3 mm. The employment of these nozzles in the experiment greatly improved the electron beam quality. After these optimizations, the laser-driven electron accelerator now yields monoenergetic electron pulses with energies up to 50 MeV and charges between one and ten pC. The electron beam has a typical divergence of 5 mrad and comprises an energy spectrum that is virtually free from low energetic background. The electron pulse duration could not yet be determined experimentally but simulations point towards values in the range of 1 fs. The acceleration gradient is estimated from simulation and experiment to be approximately 0.5 TV/m. The

Optical oscillator-amplifier laser configuration

International Nuclear Information System (INIS)

McAllister, G.L.

1975-01-01

A laser is described that has incorporated therein an oscillator formed by a pair of mirrors, at least one of the mirrors being positioned outside of the envelope. The mirrors are dimensioned and spaced from each other so that the resonator has a relatively low Fresnel number and is operated unstably. The entire surface of one of these mirrors is convex and diffracts a portion of the energy outside of the oscillator region. Also incorporated into the laser is an amplifier region defined by a separate pair of mirrors which receive the energy diffracted from the oscillator region. The second pair of mirrors form an optical system with a high Fresnel number. A filter, modulator or other control for the laser signal may be placed outside the laser envelope in the optical path of the oscillator

TOF technique for laser-driven proton beam diagnostics for the ELIMED beamline

International Nuclear Information System (INIS)

Milluzzo, G.; Scuderi, V.; Amico, A.G.; Cirrone, G.A.P.; Cuttone, G.; Larosa, G.; Leanza, R.; Petringa, G.; Pipek, J.; Romano, F.; Napoli, M. De; Dostal, J.; Margarone, D.; Schillaci, F.; Velyhan, A.

2017-01-01

The Time of Flight (TOF) method for laser-driven ion beam diagnostics has been extensively investigated so far for low energy ion diagnostics and several works, reported in literature [1,2], have shown its efficiency in the measurement of particle beam characteristics such as ion species, energy spectrum and current. Moreover, such technique allows obtaining a shot-to-shot on-line monitoring of optically accelerated particles, necessary to control the reproducibility of the accelerated beam and to deliver a beam suitable for any kind of applications. For this reason, the ELIMED beamline [3,4], which will be entirely developed at INFN-LNS and installed in 2017 within the ion beamline ELIMAIA (ELI Multidisciplinary Applications of laser-Ion Acceleration) experimental hall at ELI-Beamlines in Prague, will be equipped with an on-line diagnostics system composed by silicon carbide and diamond detectors, using the TOF technique. In this contribution, the procedure developed for TOF signal analysis will be briefly reported.

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

International Nuclear Information System (INIS)

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

1988-01-01

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

Pulsed radiobiology with laser-driven plasma accelerators

Science.gov (United States)

Giulietti, Antonio; Grazia Andreassi, Maria; Greco, Carlo

2011-05-01

Recently, a high efficiency regime of acceleration in laser plasmas has been discovered, allowing table top equipment to deliver doses of interest for radiotherapy with electron bunches of suitable kinetic energy. In view of an R&D program aimed to the realization of an innovative class of accelerators for medical uses, a radiobiological validation is needed. At the present time, the biological effects of electron bunches from the laser-driven electron accelerator are largely unknown. In radiobiology and radiotherapy, it is known that the early spatial distribution of energy deposition following ionizing radiation interactions with DNA molecule is crucial for the prediction of damages at cellular or tissue levels and during the clinical responses to this irradiation. The purpose of the present study is to evaluate the radio-biological effects obtained with electron bunches from a laser-driven electron accelerator compared with bunches coming from a IORT-dedicated medical Radio-frequency based linac's on human cells by the cytokinesis block micronucleus assay (CBMN). To this purpose a multidisciplinary team including radiotherapists, biologists, medical physicists, laser and plasma physicists is working at CNR Campus and University of Pisa. Dose on samples is delivered alternatively by the "laser-linac" operating at ILIL lab of Istituto Nazionale di Ottica and an RF-linac operating for IORT at Pisa S. Chiara Hospital. Experimental data are analyzed on the basis of suitable radiobiological models as well as with numerical simulation based on Monte Carlo codes. Possible collective effects are also considered in the case of ultrashort, ultradense bunches of ionizing radiation.

IR-laser assisted additive freeform optics manufacturing.

Science.gov (United States)

Hong, Zhihan; Liang, Rongguang

2017-08-02

Computer-controlled additive manufacturing (AM) processes, also known as three-dimensional (3D) printing, create 3D objects by the successive adding of a material or materials. While there have been tremendous developments in AM, the 3D printing of optics is lagging due to the limits in materials and tight requirements for optical applicaitons. We propose a new precision additive freeform optics manufacturing (AFOM) method using an pulsed infrared (IR) laser. Compared to ultraviolet (UV) curable materials, thermally curable optical silicones have a number of advantages, such as strong UV stability, non-yellowing, and high transmission, making it particularly suitable for optical applications. Pulsed IR laser radiation offers a distinct advantage in processing optical silicones, as the high peak intensity achieved in the focal region allows for curing the material quickly, while the brief duration of the laser-material interaction creates a negligible heat-affected zone.

Optical-Thermal Response of Laser-Irradiated Tissue

CERN Document Server

Welch, Ashley J

2011-01-01

The second edition of 'Optical-Thermal Response of Laser-Irradiated Tissue' maintains the standard of excellence established in the first edition, while adjusting the content to reflect changes in tissue optics and medical applications since 1995. The material concerning light propagation now contains new chapters devoted to electromagnetic theory for coherent light. The material concerning thermal laser-tissue interactions contains a new chapter on pulse ablation of tissue. The medical applications section now includes several new chapters on Optical Coherent Tomography, acoustic imaging, molecular imaging, forensic optics and nerve stimulation. A detailed overview is provided of the optical and thermal response of tissue to laser irradiation along with diagnostic and therapeutic examples including fiber optics. Sufficient theory is included in the book so that it is suitable for a one or two semester graduate or for senior elective courses. Material covered includes: 1. light propagation and diagnostic appl...

Etching of LiNbO/sub 3/ by laser-driven fusion of salts

International Nuclear Information System (INIS)

Ashby, C.I.H.; Brannon, P.J.

1987-01-01

Lithium niobate exhibits low reactivity with most chemical etchants. Consequently, etching a LiNbO/sub 3/ surface to produce optical structures such as ridge waveguides or grooves for fiber coupling normally requires relatively slow processes such as ion milling. The authors have developed a laser-driven chemical etching process for etching highly unreactive ionic solids based on the fusion of salts in the molten phase and show that the etch rate can be more than 100 times faster than ion milling rates. This process involves spatially localized melting of LiNbO/sub 3/ by high-power density laser pulses with photon energies in excess of the band gap of LiNbO/sub 3/. While molten, LiNbO/sub 3/ undergoes reaction with a surface coating of KF to form niobium oxyfluoride anions by fusion of the salts. The resulting solid is highly water soluble. The insolubility of LiNbO/sub 3/ permits subsequent removal of only the irradiated area by rinsing in water. Surface morphology is determined by laser power density. The process exhibits a wavelength dependence

Laser-driven acceleration with Bessel and Gaussian beams

International Nuclear Information System (INIS)

Hafizi, B.; Esarey, E.; Sprangle, P.

1997-01-01

The possibility of enhancing the energy gain in laser-driven accelerators by using Bessel laser beams is examined. Scaling laws are derived for the propagation length, acceleration gradient, and energy gain in various accelerators for both Gaussian and Bessel beam drivers. For equal beam powers, the energy gain can be increased by a factor of N 1/2 by utilizing a Bessel beam with N lobes, provided that the acceleration gradient is linearly proportional to the laser field. This is the case in the inverse free electron laser and the inverse Cherenkov accelerators. If the acceleration gradient is proportional to the square of the laser field (e.g., the laser wakefield, plasma beat wave, and vacuum beat wave accelerators), the energy gain is comparable with either beam profile. copyright 1997 American Institute of Physics

Laser-ablation-based ion source characterization and manipulation for laser-driven ion acceleration

Science.gov (United States)

Sommer, P.; Metzkes-Ng, J.; Brack, F.-E.; Cowan, T. E.; Kraft, S. D.; Obst, L.; Rehwald, M.; Schlenvoigt, H.-P.; Schramm, U.; Zeil, K.

2018-05-01

For laser-driven ion acceleration from thin foils (∼10 μm–100 nm) in the target normal sheath acceleration regime, the hydro-carbon contaminant layer at the target surface generally serves as the ion source and hence determines the accelerated ion species, i.e. mainly protons, carbon and oxygen ions. The specific characteristics of the source layer—thickness and relevant lateral extent—as well as its manipulation have both been investigated since the first experiments on laser-driven ion acceleration using a variety of techniques from direct source imaging to knife-edge or mesh imaging. In this publication, we present an experimental study in which laser ablation in two fluence regimes (low: F ∼ 0.6 J cm‑2, high: F ∼ 4 J cm‑2) was applied to characterize and manipulate the hydro-carbon source layer. The high-fluence ablation in combination with a timed laser pulse for particle acceleration allowed for an estimation of the relevant source layer thickness for proton acceleration. Moreover, from these data and independently from the low-fluence regime, the lateral extent of the ion source layer became accessible.

OPTICAL DEFLECTOR CREATION FOR LASER THERAPEUTIC DEVICES

Directory of Open Access Journals (Sweden)

V. N. Baranov

2014-03-01

Full Text Available The paper deals with creation of optical deflector for management of laser radiation in physiotherapeutic devices. Design features and operation principles of electro-optical, optical-acoustic and mechanical deflectors, giving the possibility to carry out continuous or discrete scanning of a laser beam are shown. Operation mechanism of the mechanical type deflector on the example of domestic laser therapeutic scanners is described in detail. Application possibility in clinical practice for heating technique of the acupuncture points by volumetric scanning of tissues by the radiation of semiconductor lasers on wave lengths equal to 0,67 and 0,85 μm is investigated. Creation justification of the new type deflector is given. Comparison between stable and labile techniques of radiation is carried out. It is shown that more intensive warming up of a skin surface in acupuncture point projection is observed at volumetric scanning, rather than at planar scanning by laser beams. Temperature increase on a skin surface in projection of acupuncture points is detected at radiation in both the visible spectrum range (0,67 μm and the infrared range (0,85 μm. It gives the possibility to apply this scanning method to thermal photo-activation of the point and to extend an existing arsenal of laser reflexology methods. The optical deflector is offered for medical industry, making it possible to carry out volumetric scanning of a laser beam and to facilitate the medical personnel’s work in laser therapy and reflexology consulting rooms.

Laser-driven soft-X-ray undulator source

International Nuclear Information System (INIS)

Fuchs, Matthias

2010-01-01

The experimental results described in this thesis demonstrate the successful synergy between the research fields described above: the development of an undulator source driven by laser-plasma accelerated electron beams. First efforts in this new field have led to the production of radiation in the visible to infrared part of the electromagnetic spectrum [Schlenvoigt et al., 2008]. In contrast to these early achievements, the experiment described here shows the successful production of laser-driven undulator radiation in the soft-X-ray range with a remarkable reproducibility. The source produced tunable, collimated beams with a wavelength of ∝17 nm from a compact setup. Undulator spectra were detected in ∝70% of consecutive driver-laser shots, which is a remarkable reproducibility for a first proof-of-concept demonstration using ultra-high intensity laser systems. This can be attributed to a stable electron acceleration scheme as well as to the first application of miniature magnetic quadrupole lenses with laseraccelerated beams. The lenses significantly reduce the electron beam divergence and its angular shot-to-shot fluctuations The setup of this experiment is the foundation of potential university-laboratory-sized, highly-brilliant hard X-ray sources. By increasing the electron energy to about 1 GeV, X-ray pulses with an expected duration of ∝10 fs and a photon energy of 1 keV could be produced in an almost identical arrangement. It can also be used as a testbed for the development of a free-electron laser of significantly smaller dimension than facilities based on conventional accelerators [Gruener et al., 2007]. Such compact sources have the potential for application in many fields of science. In addition, these developments could lead to ideal sources for ultrafast pump-probe experiments due to the perfect synchronization of the X-ray beam to the driver laser. (orig.)

Laser-driven soft-X-ray undulator source

Energy Technology Data Exchange (ETDEWEB)

Fuchs, Matthias

2010-08-04

The experimental results described in this thesis demonstrate the successful synergy between the research fields described above: the development of an undulator source driven by laser-plasma accelerated electron beams. First efforts in this new field have led to the production of radiation in the visible to infrared part of the electromagnetic spectrum [Schlenvoigt et al., 2008]. In contrast to these early achievements, the experiment described here shows the successful production of laser-driven undulator radiation in the soft-X-ray range with a remarkable reproducibility. The source produced tunable, collimated beams with a wavelength of {proportional_to}17 nm from a compact setup. Undulator spectra were detected in {proportional_to}70% of consecutive driver-laser shots, which is a remarkable reproducibility for a first proof-of-concept demonstration using ultra-high intensity laser systems. This can be attributed to a stable electron acceleration scheme as well as to the first application of miniature magnetic quadrupole lenses with laseraccelerated beams. The lenses significantly reduce the electron beam divergence and its angular shot-to-shot fluctuations The setup of this experiment is the foundation of potential university-laboratory-sized, highly-brilliant hard X-ray sources. By increasing the electron energy to about 1 GeV, X-ray pulses with an expected duration of {proportional_to}10 fs and a photon energy of 1 keV could be produced in an almost identical arrangement. It can also be used as a testbed for the development of a free-electron laser of significantly smaller dimension than facilities based on conventional accelerators [Gruener et al., 2007]. Such compact sources have the potential for application in many fields of science. In addition, these developments could lead to ideal sources for ultrafast pump-probe experiments due to the perfect synchronization of the X-ray beam to the driver laser. (orig.)

Optically pumped ultraviolet and infrared lasers driven by exploding metal films and wires

International Nuclear Information System (INIS)

Jones, C.R.; Ware, K.D.

1983-01-01

The 342-nm molecular iodine and 1315-nm atomic iodine lasers have been optically pumped by intense light from exploding-metal-film and exploding-wire discharges. Brightness temperatures for the exploding-film discharges were approx. 25,000 K and for the wire discharges were approx. 30,000 K. For the I 2 laser the 3.5-cm-diameter by 40-cm-long pumped volume lies adjacent to the wire or film of the same length. Pressures of 1 to 6 torr I 2 and 1 to 3 atm SF, CF 4 , or Ar were used in the stainless-steel cell. Using 20-μF capacitance charged to 40 kV, a 0.25-mm tungsten wire, 3-torr I 2 , and a 2-atm SF 6 , an energy of 2 J was obtained from the laser in a pulse of 8-μs duration. The specific output energy was 7 J/l. Substitution of a cylindrical Al film for the wire, under otherwise similar conditions, led to a X10 output energies and efficiencies were obtained with similar input energy. An output pulse of 12 J and 12-μs duration was measured for a specific output energy of 18 J/l. A laser energy of 110 J in a 20-us-long pulse has been measured from atomic iodine using a wire discharge along the axis of a larger cell. The active volume available was 20 cm in diameter and 80 cm in length. Input energy was 32 kJ. In similar measurements using a cylindrical Al film for discharge initiation, the measured output energy was 40 J

Quasi-monoenergetic ion beam acceleration by laser-driven shock and solitary waves in near-critical plasmas

International Nuclear Information System (INIS)

Zhang, W. L.; Qiao, B.; Huang, T. W.; Shen, X. F.; You, W. Y.; Yan, X. Q.; Wu, S. Z.; Zhou, C. T.; He, X. T.

2016-01-01

Ion acceleration in near-critical plasmas driven by intense laser pulses is investigated theoretically and numerically. A theoretical model has been given for clarification of the ion acceleration dynamics in relation to different laser and target parameters. Two distinct regimes have been identified, where ions are accelerated by, respectively, the laser-induced shock wave in the weakly driven regime (comparatively low laser intensity) and the nonlinear solitary wave in the strongly driven regime (comparatively high laser intensity). Two-dimensional particle-in-cell simulations show that quasi-monoenergetic proton beams with a peak energy of 94.6 MeV and an energy spread 15.8% are obtained by intense laser pulses at intensity I_0 = 3 × 10"2"0" W/cm"2 and pulse duration τ = 0.5 ps in the strongly driven regime, which is more advantageous than that got in the weakly driven regime. In addition, 233 MeV proton beams with narrow spread can be produced by extending τ to 1.0 ps in the strongly driven regime.

Quasi-monoenergetic ion beam acceleration by laser-driven shock and solitary waves in near-critical plasmas

Energy Technology Data Exchange (ETDEWEB)

Zhang, W. L.; Qiao, B., E-mail: bqiao@pku.edu.cn; Huang, T. W.; Shen, X. F.; You, W. Y. [Center for Applied Physics and Technology, HEDPS, and State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006 (China); Yan, X. Q. [Center for Applied Physics and Technology, HEDPS, and State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Wu, S. Z. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Zhou, C. T.; He, X. T. [Center for Applied Physics and Technology, HEDPS, and State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)

2016-07-15

Ion acceleration in near-critical plasmas driven by intense laser pulses is investigated theoretically and numerically. A theoretical model has been given for clarification of the ion acceleration dynamics in relation to different laser and target parameters. Two distinct regimes have been identified, where ions are accelerated by, respectively, the laser-induced shock wave in the weakly driven regime (comparatively low laser intensity) and the nonlinear solitary wave in the strongly driven regime (comparatively high laser intensity). Two-dimensional particle-in-cell simulations show that quasi-monoenergetic proton beams with a peak energy of 94.6 MeV and an energy spread 15.8% are obtained by intense laser pulses at intensity I{sub 0} = 3 × 10{sup 20 }W/cm{sup 2} and pulse duration τ = 0.5 ps in the strongly driven regime, which is more advantageous than that got in the weakly driven regime. In addition, 233 MeV proton beams with narrow spread can be produced by extending τ to 1.0 ps in the strongly driven regime.

Integrated semiconductor twin-microdisk laser under mutually optical injection

Energy Technology Data Exchange (ETDEWEB)

Zou, Ling-Xiu; Liu, Bo-Wen; Lv, Xiao-Meng; Yang, Yue-De; Xiao, Jin-Long; Huang, Yong-Zhen, E-mail: yzhuang@semi.ac.cn [State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China)

2015-05-11

We experimentally study the characteristics of an integrated semiconductor twin-microdisk laser under mutually optical injection through a connected optical waveguide. Based on the lasing spectra, four-wave mixing, injection locking, and period-two oscillation states are observed due to the mutually optical injection by adjusting the injected currents applied to the two microdisks. The enhanced 3 dB bandwidth is realized for the microdisk laser at the injection locking state, and photonic microwave is obtained from the electrode of the microdisk laser under the period-two oscillation state. The plentifully dynamical states similar as semiconductor lasers subject to external optical injection are realized due to strong optical interaction between the two microdisks.

Precision Spectroscopy, Diode Lasers, and Optical Frequency Measurement Technology

Science.gov (United States)

Hollberg, Leo (Editor); Fox, Richard (Editor); Waltman, Steve (Editor); Robinson, Hugh

1998-01-01

This compilation is a selected set of reprints from the Optical Frequency Measurement Group of the Time and Frequency Division of the National Institute of Standards and Technology, and consists of work published between 1987 and 1997. The two main programs represented here are (1) development of tunable diode-laser technology for scientific applications and precision measurements, and (2) research toward the goal of realizing optical-frequency measurements and synthesis. The papers are organized chronologically in five, somewhat arbitrarily chosen categories: Diode Laser Technology, Tunable Laser Systems, Laser Spectroscopy, Optical Synthesis and Extended Wavelength Coverage, and Multi-Photon Interactions and Optical Coherences.

Alternative laser system for cesium magneto-optical trap via optical injection locking to sideband of a 9-GHz current-modulated diode laser.

Science.gov (United States)

Diao, Wenting; He, Jun; Liu, Zhi; Yang, Baodong; Wang, Junmin

2012-03-26

By optical injection of an 852-nm extended-cavity diode laser (master laser) to lock the + 1-order sideband of a ~9-GHz-current-modulated diode laser (slave laser), we generate a pair of phase-locked lasers with a frequency difference up to ~9-GHz for a cesium (Cs) magneto-optical trap (MOT) with convenient tuning capability. For a cesium MOT, the master laser acts as repumping laser, locked to the Cs 6S₁/₂ (F = 3) - 6P₃/₂ (F' = 4) transition. When the + 1-order sideband of the 8.9536-GHz-current-modulated slave laser is optically injection-locked, the carrier operates on the Cs 6S₁/₂ (F = 4) - 6P₃/₂ (F' = 5) cooling cycle transition with -12 MHz detuning and acts as cooling/trapping laser. When carrying a 9.1926-GHz modulation signal, this phase-locked laser system can be applied in the fields of coherent population trapping and coherent manipulation of Cs atomic ground states.

Laser-driven electron beam and radiation sources for basic, medical and industrial sciences

Science.gov (United States)

NAKAJIMA, Kazuhisa

2015-01-01

To date active research on laser-driven plasma-based accelerators have achieved great progress on production of high-energy, high-quality electron and photon beams in a compact scale. Such laser plasma accelerators have been envisaged bringing a wide range of applications in basic, medical and industrial sciences. Here inheriting the groundbreaker’s review article on “Laser Acceleration and its future” [Toshiki Tajima, (2010)],1) we would like to review recent progress of producing such electron beams due to relativistic laser-plasma interactions followed by laser wakefield acceleration and lead to the scaling formulas that are useful to design laser plasma accelerators with controllability of beam energy and charge. Lastly specific examples of such laser-driven electron/photon beam sources are illustrated. PMID:26062737

Laser based analysis using a passively Q-switched laser employing analysis electronics and a means for detecting atomic optical emission of the laser media

Science.gov (United States)

Woodruff, Steven D.; Mcintyre, Dustin L.

2016-03-29

A device for Laser based Analysis using a Passively Q-Switched Laser comprising an optical pumping source optically connected to a laser media. The laser media and a Q-switch are positioned between and optically connected to a high reflectivity mirror (HR) and an output coupler (OC) along an optical axis. The output coupler (OC) is optically connected to the output lens along the optical axis. A means for detecting atomic optical emission comprises a filter and a light detector. The optical filter is optically connected to the laser media and the optical detector. A control system is connected to the optical detector and the analysis electronics. The analysis electronics are optically connected to the output lens. The detection of the large scale laser output production triggers the control system to initiate the precise timing and data collection from the detector and analysis.

The theory of optical black hole lasers

Energy Technology Data Exchange (ETDEWEB)

Gaona-Reyes, José L., E-mail: jgaona@fis.cinvestav.mx; Bermudez, David, E-mail: dbermudez@fis.cinvestav.mx

2017-05-15

The event horizon of black holes and white holes can be achieved in the context of analogue gravity. It was proven for a sonic case that if these two horizons are close to each other their dynamics resemble a laser, a black hole laser, where the analogue of Hawking radiation is trapped and amplified. Optical analogues are also very successful and a similar system can be achieved there. In this work we develop the theory of optical black hole lasers and prove that the amplification is also possible. Then, we study the optical system by determining the forward propagation of modes, obtaining an approximation for the phase difference which governs the amplification, and performing numerical simulations of the pulse propagation of our system. - Highlights: • We develop the conditions to obtain the kinematics of the optical black hole laser. • We prove the amplification of Hawking radiation for the optical case. • We derive the forward propagation of modes and check the result of the backward case. • A model is proposed to calculate the phase difference and the amplification rate. • We perform numerical simulations of a pulse between two solitons forming a cavity.

Optical laser systems at the Linac Coherent Light Source

Energy Technology Data Exchange (ETDEWEB)

Minitti, Michael P.; Robinson, Joseph S.; Coffee, Ryan N.; Edstrom, Steve; Gilevich, Sasha; Glownia, James M.; Granados, Eduardo; Hering, Philippe; Hoffmann, Matthias C.; Miahnahri, Alan; Milathianaki, Despina; Polzin, Wayne; Ratner, Daniel; Tavella, Franz; Vetter, Sharon; Welch, Marc; White, William E.; Fry, Alan R., E-mail: alanfry@slac.stanford.edu [Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States)

2015-04-22

This manuscript serves as a reference to describe the optical laser sources and capabilities at the Linac Coherent Light Source. Ultrafast optical lasers play an essential role in exploiting the unique capabilities of recently commissioned X-ray free-electron laser facilities such as the Linac Coherent Light Source (LCLS). Pump–probe experimental techniques reveal ultrafast dynamics in atomic and molecular processes and reveal new insights in chemistry, biology, material science and high-energy-density physics. This manuscript describes the laser systems and experimental methods that enable cutting-edge optical laser/X-ray pump–probe experiments to be performed at LCLS.

Method and system for communicating with a laser power driver

Science.gov (United States)

Telford, Steven

2017-07-18

A system for controlling a plurality of laser diodes includes an optical transmitter coupled to the laser diode driver for each laser diode. An optical signal including bi-phase encoded data is provided to each laser diode driver. The optical signal includes current level and pulse duration information at which each of the diodes is to be driven. Upon receiving a trigger signal, the laser diode drivers operate the laser diodes using the current level and pulse duration information to output a laser beam.

Design and Status of the ELIMED Beam Line for Laser-Driven Ion Beams

Directory of Open Access Journals (Sweden)

G. A. Pablo Cirrone

2015-08-01

Full Text Available Charged particle acceleration using ultra-intense and ultra-short laser pulses has gathered a strong interest in the scientific community and it is now one of the most attractive topics in the relativistic laser-plasma interaction research. Indeed, it could represent the future of particle acceleration and open new scenarios in multidisciplinary fields, in particular, medical applications. One of the biggest challenges consists of using, in a future perspective, high intensity laser-target interaction to generate high-energy ions for therapeutic purposes, eventually replacing the old paradigm of acceleration, characterized by huge and complex machines. The peculiarities of laser-driven beams led to develop new strategies and advanced techniques for transport, diagnostics and dosimetry of the accelerated particles, due to the wide energy spread, the angular divergence and the extremely intense pulses. In this framework, the realization of the ELIMED (ELI-Beamlines MEDical applications beamline, developed by INFN-LNS (Catania, Italy and installed in 2017 as a part of the ELIMAIA beamline at the ELI-Beamlines (Extreme Light Infrastructure Beamlines facility in Prague, has the aim to investigate the feasibility of using laser-driven ion beams in multidisciplinary applications. ELIMED will represent the first user’s open transport beam line where a controlled laser-driven ion beam will be used for multidisciplinary and medical studies. In this paper, an overview of the beamline, with a detailed description of the main transport elements, will be presented. Moreover, a description of the detectors dedicated to diagnostics and dosimetry will be reported, with some preliminary results obtained both with accelerator-driven and laser-driven beams.

Flattened optical frequency-locked multi-carrier generation by cascading one DML and one phase modulator driven by different RF frequency clocks

International Nuclear Information System (INIS)

Li, Xinying; Yu, Jianjun; Zhang, Junwen; Chi, Nan

2013-01-01

We propose a novel scheme for flattened optical frequency-locked multi-carrier generation based on one directly modulated laser (DML) and one phase modulator (PM) in cascade driven by different sinusoidal radio-frequency (RF) clocks. We experimentally demonstrate that when the clock frequencies for the cascaded DML and the PM are respectively 12.5 GHz and 25 GHz, over 24 optical subcarriers can be generated with 12.5-GHz frequency spacing and amplitude fluctuation less than 3 dB. Furthermore, the number of generated optical subcarriers can be further increased when we increase the driving power for the DML. (letter)

Advanced in Nonlinear Optics and Laser Research and Development

International Nuclear Information System (INIS)

Jackel, S.; Kotler, Z; Lavi, R.; Sternklar, S.

1996-01-01

The Nonlinear Optics Group (NLOG) at Soreq NRC is engaged in the development of fundamental and applied technology in the related fields of nonlinear optics and laser development. Our work in nonlinear optics started with the goal of improving laser performance. These efforts were successful and opened the way for R and D in nonlinear optics for other applications. Today we use nonlinear optics to enable continuous tunability of lasers, control the path of light beams, modulate a light signal rapidly, provide optical data storage, and supply new means of microscopically probing biological and inorganic samples. Technology maturation and interaction with users will show which aspects of nonlinear optics will make the most impact

Feasibility of Optical Transition Radiation Imaging for Laser-driven Plasma Accelerator Electron-Beam Diagnostics

Energy Technology Data Exchange (ETDEWEB)

Lumpkin, A. H. [Fermilab; Rule, D. W. [Unlisted, US, MD; Downer, M. C. [Texas U.

2017-10-09

We report the initial considerations of using linearly polarized optical transition radiation (OTR) to characterize the electron beams of laser plasma accelerators (LPAs) such as at the Univ. of Texas at Austin. The two LPAs operate at 100 MeV and 2-GeV, and they currently have estimated normalized emittances at ~ 1-mm mrad regime with beam divergences less than 1/γ and beam sizes to be determined at the micron level. Analytical modeling results indicate the feasibility of using these OTR techniques for the LPA applications.

The Application of Cryogenic Laser Physics to the Development of High Average Power Ultra-Short Pulse Lasers

Directory of Open Access Journals (Sweden)

David C. Brown

2016-01-01

Full Text Available Ultrafast laser physics continues to advance at a rapid pace, driven primarily by the development of more powerful and sophisticated diode-pumping sources, the development of new laser materials, and new laser and amplification approaches such as optical parametric chirped-pulse amplification. The rapid development of high average power cryogenic laser sources seems likely to play a crucial role in realizing the long-sought goal of powerful ultrafast sources that offer concomitant high peak and average powers. In this paper, we review the optical, thermal, thermo-optic and laser parameters important to cryogenic laser technology, recently achieved laser and laser materials progress, the progression of cryogenic laser technology, discuss the importance of cryogenic laser technology in ultrafast laser science, and what advances are likely to be achieved in the near-future.

Comparison of optical feedback dynamics of InAs/GaAs quantum-dot lasers emitting solely on ground or excited states.

Science.gov (United States)

Lin, Lyu-Chih; Chen, Chih-Ying; Huang, Heming; Arsenijević, Dejan; Bimberg, Dieter; Grillot, Frédéric; Lin, Fan-Yi

2018-01-15

We experimentally compare the dynamics of InAs/GaAs quantum dot lasers under optical feedback emitting exclusively on ground states (GSs) or excited states (ESs). By varying the feedback parameters and putting focus either on their short or long cavity regions, various periodic and chaotic oscillatory states are found. The GS laser is shown to be more resistant to feedback, benefiting from its strong relaxation oscillation damping. In contrast, the ES laser can easily be driven into complex dynamics. While the GS laser is of importance for the development of isolator-free transmitters, the ES laser is essential for applications taking advantages of chaos.

Hydrodynamic analysis of laser-driven cylindrical implosions

Energy Technology Data Exchange (ETDEWEB)

Ramis, R. [E.T.S.I. Aeronáuticos, Universidad Politécnica de Madrid (Spain)

2013-08-15

Three-dimensional hydrodynamic simulations are performed to study laser-driven cylindrical implosions in the context of experiments (F. Perez et al., Plasma Phys. Controlled Fusion 51, 124035 (2009)) carried out at the Rutherford Appleton Laboratory in the framework of the HiPER project. The analysis is carried out by using the 3D version of the hydrocode MULTI (R. Ramis et al., Comput. Phys. Commun. 49, 475-505 (1988)). The influence of the main laser parameters on implosion performance and symmetry is consistently studied and compared with the results of 2D analysis. Furthermore, the effects of uncertainties in laser irradiation (pointing, focusing, power balance, and time jitter) on implosion performance (average peak density and temperature) are studied by means of statistical analysis.

Measurement of pzz of the laser-driven polarized deuterium target

International Nuclear Information System (INIS)

Jones, C.E.; Coulter, K.P.; Holt, R.J.; Poelker, M.; Potterveld, D.P.; Kowalczyk, R.S.; Buchholz, M.; Neal, J.; van den Brand, J.F.J.

1993-01-01

The question of whether nuclei are polarized as a result of H-H (D-D) spin-exchange collisions within the relatively dense gas of a laser-driven source of polarized hydrogen (deuterium) can be addressed directly by measuring the nuclear polarization of atoms from the source. The feasibility of using a polarimeter based on the D + T → n + 4 He reaction to measure the tensor polarization of deuterium in an internal target fed by the laser-driven source has been tested. The device and the measurements necessary to test the spin-exchange polarization theory are described

Laser driven fusion fission hybrids

International Nuclear Information System (INIS)

Hansen, L.F.; Maniscalco, J.A.

1977-11-01

The role of the fusion-fission hybrid reactor (FFHR) as a fissile fuel and/or power producer is discussed. As long range options to supply the world energy needs, hybrid-fueled thermal-burner reactors are compared to liquid metal fast breeder reactors (LMFBR). A discussion of different fuel cycles (thorium, depleted uranium, and spent fuel) is presented in order to compare the energy multiplication, the production of fissile fuel, the laser efficiency and pellet gain requirements of the hybrid reactor. Lawrence Livermore Laboratory (LLL) has collaborated with Bechtel Corporation and with Westinghouse in two engineering design studies of laser fusion driven hybrid power plants. The hybrid designs which have resulted from these two studies are briefly described and analyzed by considering operational parameters, such as energy multiplication, power density, burn-up and plutonium production as a function time

Proceedings of the IEEE laser and electro-optics society annual meeting

International Nuclear Information System (INIS)

Hudson, M.J.B.; Raney, H.; Raney, D.; Spalaris, C.N.

1990-01-01

This book is covered under the following headings: Electro-optic systems; Emerging laser technology; Optical sensors and measurements; Optoelectronics; Semiconductor diode lasers; Solid state lasers; UV and short wavelength; Applied optical diagnostics of semiconductor materials and devices symposium and optical sensors and measurements; and Applied optical diagnostics of semiconductor materials and devices symposium

Acousto-optic replication of ultrashort laser pulses

Science.gov (United States)

Yushkov, Konstantin B.; Molchanov, Vladimir Ya.; Ovchinnikov, Andrey V.; Chefonov, Oleg V.

2017-10-01

Precisely controlled sequences of ultrashort laser pulses are required in various scientific and engineering applications. We developed a phase-only acousto-optic pulse shaping method for replication of ultrashort laser pulses in a TW laser system. A sequence of several Fourier-transform-limited pulses is generated from a single femtosecond laser pulse by means of applying a piecewise linear phase modulation over the whole emission spectrum. Analysis demonstrates that the main factor which limits maximum delay between the pulse replicas is spectral resolution of the acousto-optic dispersive delay line used for pulse shaping. In experiments with a Cr:forsterite laser system, we obtained delays from 0.3 to 3.5 ps between two replicas of 190 fs transform-limited pulses at the central wavelength of laser emission, 1230 nm.

Laser experimental system as teaching aid for demonstrating basic phenomena of laser feedback

International Nuclear Information System (INIS)

Xu, Ling; Zhao, Shijie; Zhang, Shulian

2015-01-01

An experimental laser teaching system is developed to demonstrate laser feedback phenomena, which bring great harm to optical communication and benefits to precision measurement. The system consists of an orthogonally polarized He-Ne laser, a feedback mirror which reflects the laser output light into the laser cavity, and an optical attenuator which changes the intensity of the feedback light. As the feedback mirror is driven by a piezoelectric ceramic, the attenuator is adjusted and the feedback mirror is tilted, the system can demonstrate many basic laser feedback phenomena, including weak, moderate and strong optical feedback, multiple feedback and polarization flipping. Demonstrations of these phenomena can give students a better understanding about the intensity and polarization of lasers. The system is well designed and assembled, simple to operate, and provides a valuable teaching aid at an undergraduate level. (paper)

Femtosecond Laser Structuring in Optical Fiber and Transparent Films

Directory of Open Access Journals (Sweden)

Herman Peter R.

2013-11-01

Full Text Available Femtosecond laser processing is optimized for writing optical circuits, optical resonators, and microfluidic devices inside the cladding of single-mode optical fiber that couple efficiently with the fiber core waveguide. The laser processes open new directions towards Labon-a-Fiber.

NIF small optics laser damage test specifications

International Nuclear Information System (INIS)

Sheehan, L

1999-01-01

The Laser Damage Group is currently conducting tests on small optics samples supplied for initial evaluation of potential NIF suppliers. This document is meant to define the specification of laser-induced damage for small optics and the test methods used to collect the data. A rating system which will be applied for vendor selection is presented

Development of high repetition rate ultra-short pulse solid state lasers pumped by laser diodes

International Nuclear Information System (INIS)

Ueda, Ken-ichi; Lu, Jianren; Takaichi, Kazunori; Yagi, Hideki; Yanagitani, Takakimi; Kaminskii, Alexander; Kawanaka, Junji

2004-01-01

A novel technique for ceramic lasers has been developed recently. Self-energy-driven sintering of nano-and micro particles created the fully transparent Nd:YAG ceramics. The ceramic YAG demonstrated high efficiency operation (optical-to-optical conversion of 60% in end pumping) and solid-phase crystals growth and the possible scaling were investigated principally. Typical performance of ceramic YAG laser has been reviewed. The present status and future prospect of the ceramic lasers technologies were discussed. (author)

Beam transport optics for high-power laser systems

International Nuclear Information System (INIS)

Taylor, J.R.

1995-01-01

Beam transport optics receive output energy from the laser cavity and deliver it to the work site. Depending on the application, this may require a few simple elements or large complex systems. Collection of the laser energy depends on the spatial and temporal energy distribution as well as the wavelength and polarization of the laser cavity and output coupler. Transport optics can perform a variety of functions, including beam formatting, frequency doubling, and distribution to one or more work sites while maintaining or even improving the beam quality. The beam may be delivered to work sites as focused spots or images, projected to distant targets, or propagated through various media for sensing or photochemical processing. Design may involve optical modeling of the system, including diffraction effects and thermal management. A Gaussian beam profile is often used for convenience in modeling. When deviations from this ideal profile need to be considered, it is necessary to characterize the laser beam in detail. Design of the transport system requires understanding of the interaction of the laser energy with optical materials and components. Practical considerations include mounting the optics without stress and with the stability suitable for the intended application. Requirements for beam direction, stability, size, shape, and quality dictate the design approach for each specific situation. Attention also must be given to reliability, environmental, and commercial requirements. Damage to optics in high-power laser systems is a common concern. Environmental problems such as atmospheric turbulence, contamination by dust or vapor from the work site or other sources, or absorption of water vapor can directly degrade beam quality. Other potentially significant optical performance effects may result from instability and aging of the optics, temperature, humidity, pressure, transmitted vibration, and contamination from the work site or other sources

Laser driven particle acceleration

International Nuclear Information System (INIS)

Faure, J.

2009-06-01

This dissertation summarizes the last ten years of research at the Laboratory of Applied Optics on laser-plasma based electron acceleration. The main result consists of the development and study of a relativistic electron source with unique properties: high energy (100-300 MeV) in short distances (few millimeters), mono-energetic, ultra-short (few fs), stable and tunable. The manuscript describes the steps that led to understanding the physics, and then mastering it in order to produce this new electron source. Non linear propagation of the laser pulse in the plasma is first presented, with phenomena such as non linear wakefield excitation, relativistic and ponderomotive self-focusing in the short pulse regime, self-compression. Acceleration and injection of electrons are then reviewed from a theoretical perspective. Experimental demonstrations of self-injection in the bubble regime and then colliding pulse injection are then presented. These experiments were among the first to produce monoenergetic, high quality, stable and tunable electron beams from a laser-plasma accelerator. The last two chapters are dedicated to the characterization of the electron beam using transition radiation and to its applications to gamma radiography and radiotherapy. Finally, the perspectives of this research are presented in the conclusion. Scaling laws are used to determine the parameters that the electron beams will reach using peta-watt laser systems currently under construction. (author)

Optical properties of polydimethylsiloxane (PDMS) during nanosecond laser processing

Energy Technology Data Exchange (ETDEWEB)

Stankova, N.E., E-mail: nestankova@yahoo.com [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsaridradsko shose Boul., Sofia 1784 (Bulgaria); Atanasov, P.A.; Nikov, Ru.G.; Nikov, R.G.; Nedyalkov, N.N.; Stoyanchov, T.R. [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tsaridradsko shose Boul., Sofia 1784 (Bulgaria); Fukata, N. [International Center for Materials for NanoArchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan); Kolev, K.N.; Valova, E.I.; Georgieva, J.S.; Armyanov, St.A. [Rostislaw Kaischew Institute of Physical Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 11, Sofia 1113 (Bulgaria)

2016-06-30

Highlights: • Ns-laser (266, 355, 532 and 1064 nm) processing of medical grade PDMS is performed. • Investigation of the optical transmittance as a function of the laser beam parameters. • Analyses of laser treated area by optical & laser microscope and μ-Raman spectrometry. • Application as (MEAs) neural interface for monitor and stimulation of neural activity. - Abstract: This article presents experimental investigations of effects of the process parameters on the medical grade polydimethylsiloxane (PDMS) elastomer processed by laser source with irradiation at UV (266 and 355 nm), VIS (532 nm) and NIR (1064 nm). Systematic experiments are done to characterize how the laser beam parameters (wavelength, fluence, and number of pulses) affect the optical properties and the chemical composition in the laser treated areas. Remarkable changes of the optical properties and the chemical composition are observed. Despite the low optical absorption of the native PDMS for UV, VIS and NIR wavelengths, successful laser treatment is accomplished due to the incubation process occurring below the polymer surface. With increasing of the fluence and the number of the pulses chemical transformations are revealed in the entire laser treated area and hence decreasing of the optical transmittance is observed. The incubation gets saturation after a certain number of pulses and the laser ablation of the material begins efficiently. At the UV and VIS wavelengths the number of the initial pulses, at which the optical transmittance begins to reduce, decreases from 16 up to 8 with increasing of the laser fluence up to 1.0, 2.5 and 10 J cm{sup −2} for 266, 355 and 532 nm, respectively. In the case of 1064 nm the optical transmittance begins to reduce at 11th pulse incident at a fluence of 13 J cm{sup −2} and the number of the pulses decreases to 8 when the fluence reaches value of 16 J cm{sup −2}. The threshold laser fluence needed to induce incubation process after certain

Fiber laser master oscillators for optical synchronization systems

International Nuclear Information System (INIS)

Winter, A.

2008-04-01

New X-ray free electron lasers (e.g. the European XFEL) require a new generation of synchronization system to achieve a stability of the FEL pulse, such that pump-probe experiments can fully utilize the ultra-short pulse duration (50 fs). An optical synchronization system has been developed based on the distribution of sub-ps optical pulses in length-stabilized fiber links. The synchronization information is contained in the precise repetition frequency of the optical pulses. In this thesis, the design and characterization of the laser serving as laser master oscillator is presented. An erbium-doped mode-locked fiber laser was chosen. Amplitude and phase noise were measured and record-low values of 0.03 % and 10 fs for the frequency range of 1 kHz to the Nyquist frequency were obtained. Furthermore, an initial proof-of-principle experiment for the optical synchronization system was performed in an accelerator environment. In this experiment, the fiber laser wase phase-locked to a microwave reference oscillator and a 500 meter long fiber link was stabilized to 12 fs rms over a range of 0.1 Hz to 20 kHz. RF signals were obtained from a photodetector without significant degradation at the end of the link. Furthermore, the laser master oscillator for FLASH was designed and is presently in fabrication and the initial infrastructure for the optical synchronization system was setup. (orig.)

Fiber laser master oscillators for optical synchronization systems

Energy Technology Data Exchange (ETDEWEB)

Winter, A.

2008-04-15

New X-ray free electron lasers (e.g. the European XFEL) require a new generation of synchronization system to achieve a stability of the FEL pulse, such that pump-probe experiments can fully utilize the ultra-short pulse duration (50 fs). An optical synchronization system has been developed based on the distribution of sub-ps optical pulses in length-stabilized fiber links. The synchronization information is contained in the precise repetition frequency of the optical pulses. In this thesis, the design and characterization of the laser serving as laser master oscillator is presented. An erbium-doped mode-locked fiber laser was chosen. Amplitude and phase noise were measured and record-low values of 0.03 % and 10 fs for the frequency range of 1 kHz to the Nyquist frequency were obtained. Furthermore, an initial proof-of-principle experiment for the optical synchronization system was performed in an accelerator environment. In this experiment, the fiber laser wase phase-locked to a microwave reference oscillator and a 500 meter long fiber link was stabilized to 12 fs rms over a range of 0.1 Hz to 20 kHz. RF signals were obtained from a photodetector without significant degradation at the end of the link. Furthermore, the laser master oscillator for FLASH was designed and is presently in fabrication and the initial infrastructure for the optical synchronization system was setup. (orig.)

A silicon-nanowire memory driven by optical gradient force induced bistability

Energy Technology Data Exchange (ETDEWEB)

Dong, B. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), Singapore 117685 (Singapore); Cai, H., E-mail: caih@ime.a-star.edu.sg; Gu, Y. D.; Kwong, D. L. [Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), Singapore 117685 (Singapore); Chin, L. K.; Ng, G. I.; Ser, W. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Huang, J. G. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), Singapore 117685 (Singapore); School of Mechanical Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Yang, Z. C. [School of Electronics Engineering and Computer Science, Peking University, Beijing 100871 (China); Liu, A. Q., E-mail: eaqliu@ntu.edu.sg [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); School of Electronics Engineering and Computer Science, Peking University, Beijing 100871 (China)

2015-12-28

In this paper, a bistable optical-driven silicon-nanowire memory is demonstrated, which employs ring resonator to generate optical gradient force over a doubly clamped silicon-nanowire. Two stable deformation positions of a doubly clamped silicon-nanowire represent two memory states (“0” and “1”) and can be set/reset by modulating the light intensity (<3 mW) based on the optical force induced bistability. The time response of the optical-driven memory is less than 250 ns. It has applications in the fields of all optical communication, quantum computing, and optomechanical circuits.

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

International Nuclear Information System (INIS)

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

2007-01-01

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

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

Science.gov (United States)

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

2012-09-01

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

Acceleration of polyethelene foils by laser driven ablation

International Nuclear Information System (INIS)

Ahlstrom, H.G.; Burginyon, G.A.; Haas, R.A.

1974-01-01

The production of thermonuclear energy, by laser driven implosion of spherical DT shells, with achievable laser technology, requires the development of an efficient and stable implosion. Certain aspects of the acceleration of the spherical shells can be studied experimentally by irradiating thin, 5 to 25 μm, polyethelene foils. The results of foil acceleration experiments performed using a Nd:YAG-Glass laser capable of producing 150 J, 1 nsec pulses will be discussed. The dynamics of the accelerated foil, the ion blow off, high energy electron spectrum (6 to 180 keV), x-ray spectrum (1 to 150 keV) the spatial distribution of the x-ray emission, the laser beam focal spot energy distribution, the laser temporal pulse shape and spectrum for reflected and transmitted radiation have all been measured simultaneously. The results of these measurements are compared with detailed numerical simulations. (U.S.)

Principles of laser spectroscopy and quantum optics

CERN Document Server

Berman, Paul R

2011-01-01

Principles of Laser Spectroscopy and Quantum Optics is an essential textbook for graduate students studying the interaction of optical fields with atoms. It also serves as an ideal reference text for researchers working in the fields of laser spectroscopy and quantum optics. The book provides a rigorous introduction to the prototypical problems of radiation fields interacting with two- and three-level atomic systems. It examines the interaction of radiation with both atomic vapors and condensed matter systems, the density matrix and the Bloch vector, and applications involving linear absorptio

Studies on a laser driven photoemissive high-brightness electron source and novel photocathodes

International Nuclear Information System (INIS)

Geng Rongli; Song Jinhu; Yu Jin

1997-01-01

A laser driven photoemissive high-brightness electron source at Beijing University is reported. Through a DC accelerating gap of 100 kV voltage, the device is capable of delivering high-brightness electron beam of 35-100 ps pulse duration when irradiated with a mode-locked YAG laser. The geometry of the gun is optimized with the aid of simulation codes EGUN and POISSON. The results of experimental studies on ion implanted photocathode and cesium telluride photocathode are given. The proposed laser driven superconducting RF gun is also discussed

The European project Hippo high-power photonics for satellite laser communications and on-board optical processing

Science.gov (United States)

Kehayas, E.; Stampoulidis, L.; Henderson, P.; Robertson, Andrew; Van Dijk, F.; Achouche, M.; Le Kernec, A.; Sotom, M.; Schuberts, F.; Brabant, T.

2017-11-01

Photonics is progressively transforming from a highly- focused technology applicable to digital communication networks into a pervasive "enabling" technology with diverse non-telecom applications. However, the centre of mass on the R&D level is still mostly driven by, and invested in, by stakeholders active in the telecoms domain. This is due to the high level of investments necessary that in turn require a large and established market for reaching break-even and generation of revenues. Photonics technology and more specifically, fibre-optic technology is moving into non-telecom business areas with great success in terms of markets captured and penetration rates. One example that cannot be overlooked is the application of fibre-optics to industrial applications, where double-digit growth rates are recorded with fibre lasers and amplifiers constantly gaining momentum. In this example, several years of R&D efforts in creating high-power amplification solutions and fibre-laser sources by the telecom sector, were piggy-backed into industrial applications and laser cutting/welding equipment that is now a strong R&D sector on its own and commercially now displacing some conventional free space laser cutting/welding.

Laser-driven hydrothermal process studied with excimer laser pulses

Science.gov (United States)

Mariella, Raymond; Rubenchik, Alexander; Fong, Erika; Norton, Mary; Hollingsworth, William; Clarkson, James; Johnsen, Howard; Osborn, David L.

2017-08-01

Previously, we discovered [Mariella et al., J. Appl. Phys. 114, 014904 (2013)] that modest-fluence/modest-intensity 351-nm laser pulses, with insufficient fluence/intensity to ablate rock, mineral, or concrete samples via surface vaporization, still removed the surface material from water-submerged target samples with confinement of the removed material, and then dispersed at least some of the removed material into the water as a long-lived suspension of nanoparticles. We called this new process, which appears to include the generation of larger colorless particles, "laser-driven hydrothermal processing" (LDHP) [Mariella et al., J. Appl. Phys. 114, 014904 (2013)]. We, now, report that we have studied this process using 248-nm and 193-nm laser light on submerged concrete, quartzite, and obsidian, and, even though light at these wavelengths is more strongly absorbed than at 351 nm, we found that the overall efficiency of LDHP, in terms of the mass of the target removed per Joule of laser-pulse energy, is lower with 248-nm and 193-nm laser pulses than with 351-nm laser pulses. Given that stronger absorption creates higher peak surface temperatures for comparable laser fluence and intensity, it was surprising to observe reduced efficiencies for material removal. We also measured the nascent particle-size distributions that LDHP creates in the submerging water and found that they do not display the long tail towards larger particle sizes that we had observed when there had been a multi-week delay between experiments and the date of measuring the size distributions. This is consistent with transient dissolution of the solid surface, followed by diffusion-limited kinetics of nucleation and growth of particles from the resulting thin layer of supersaturated solution at the sample surface.

Stability of optically injected two-state quantum-dot lasers

Energy Technology Data Exchange (ETDEWEB)

Meinecke, Stefan; Lingnau, Benjamin; Roehm, Andre; Luedge, Kathy [Institut fuer Theoretische Physik, Technische Universitaet Berlin (Germany)

2017-12-15

Simultaneous two-state lasing is a unique property of semiconductor quantum-dot (QD) lasers. This not only changes steady-state characteristics of the laser device but also its dynamic response to perturbations. In this paper we investigate the dynamic stability of QD lasers in an external optical injection setup. Compared to conventional single-state laser devices, we find a strong suppression of dynamical instabilities in two-state lasers. Furthermore, depending on the frequency and intensity of the injected light, pronounced areas of bistability between both lasing frequencies appear, which can be employed for fast optical switching in all-optical photonic computing applications. These results emphasize the suitability of QD semiconductor lasers in future integrated optoelectronic systems where a high level of stability is required. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Stability of optically injected two-state quantum-dot lasers

International Nuclear Information System (INIS)

Meinecke, Stefan; Lingnau, Benjamin; Roehm, Andre; Luedge, Kathy

2017-01-01

Simultaneous two-state lasing is a unique property of semiconductor quantum-dot (QD) lasers. This not only changes steady-state characteristics of the laser device but also its dynamic response to perturbations. In this paper we investigate the dynamic stability of QD lasers in an external optical injection setup. Compared to conventional single-state laser devices, we find a strong suppression of dynamical instabilities in two-state lasers. Furthermore, depending on the frequency and intensity of the injected light, pronounced areas of bistability between both lasing frequencies appear, which can be employed for fast optical switching in all-optical photonic computing applications. These results emphasize the suitability of QD semiconductor lasers in future integrated optoelectronic systems where a high level of stability is required. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Laser cooling in a feedback-controlled optical shaker

International Nuclear Information System (INIS)

Vilensky, Mark Y.; Averbukh, Ilya Sh.; Prior, Yehiam

2006-01-01

We explore the prospects of optical shaking, a recently suggested generic approach to laser cooling of neutral atoms and molecules. Optical shaking combines elements of Sisyphus cooling and of stochastic cooling techniques and is based on feedback-controlled interaction of particles with strong nonresonant laser fields. The feedback loop guarantees a monotonous energy decrease without a loss of particles. We discuss two types of feedback algorithms and provide an analytical estimation of their cooling rate. We study the robustness of optical shaking against noise and establish minimal stability requirements for the lasers. The analytical predictions are in a good agreement with the results of detailed numerical simulations

Theoretical and experimental studies of optical feedback on solid-state lasers

International Nuclear Information System (INIS)

Kervevan, L.

2006-12-01

The main objective of this Phd thesis was to implement solid-state lasers based on codoped Yb 3+ :Er 3+ phosphate glasses pumped by laser diode and to study their behavior when submitted to an optical feedback. This kind of lasers presents as main advantages a very high sensibility to the optical feedback due to the optical properties of the Er 3+ ion enhancing the relaxation oscillations. Moreover, the emission wavelength around 1,535 μm belongs to the eye safe spectral domain. First, we have established the rate equations of the population inversion and the electric field for a three-level laser (Yb:Er) submitted to an optical feedback. We have done a comparative study of the influence of the amplifying medium (three-level system Yb:Er or four-level system LNA:Nd) and cavity parameters on the sensitivity due to the optical feedback. The home-made lasers were implemented in optical feedback experiments allowing original measurement of speed, absolute distance or vibration for optical detection of sound restitution. The fourth part of this thesis deals with the behavior a dual frequency laser submitted to a optical feedback. Such a laser oscillates simultaneously on two polarization eigenstates whose optical frequencies are slightly different. The beating mode between these two eigenstates allows self-heterodyne detection. (author)

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

Science.gov (United States)

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

2018-04-19

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

Development of optical surface contouring technique using laser

Energy Technology Data Exchange (ETDEWEB)

Baik, Sung Hoon; Kim, Min Suk; Park, Seung Kyu

1998-12-01

Laser contouring system capable of measuring relief profiles using a line-shaped laser beam with anisotropic magnification optics composed with two cylindrical lenses was developed. The anisotropic magnification optical system allows it to obtain higher resolution in the relief profile measurements. The image processing and 3-D display software are developed to reconstruct 3-D shape. The power supply of laser diode with adaptive current control circuit is designed. (author). 4 refs., 5 tabs., 33 figs.

Seeding magnetic fields for laser-driven flux compression in high-energy-density plasmas.

Science.gov (United States)

Gotchev, O V; Knauer, J P; Chang, P Y; Jang, N W; Shoup, M J; Meyerhofer, D D; Betti, R

2009-04-01

A compact, self-contained magnetic-seed-field generator (5 to 16 T) is the enabling technology for a novel laser-driven flux-compression scheme in laser-driven targets. A magnetized target is directly irradiated by a kilojoule or megajoule laser to compress the preseeded magnetic field to thousands of teslas. A fast (300 ns), 80 kA current pulse delivered by a portable pulsed-power system is discharged into a low-mass coil that surrounds the laser target. A >15 T target field has been demonstrated using a hot spot of a compressed target. This can lead to the ignition of massive shells imploded with low velocity-a way of reaching higher gains than is possible with conventional ICF.

Suppression of dissipation in a laser-driven qubit by white noise

Energy Technology Data Exchange (ETDEWEB)

Yan, Lei-Lei [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); University of the Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Jian-Qi [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China); Jing, Jun, E-mail: junjing@jlu.edu.cn [Institute of Atomic and Molecular Physics and Provincial Key Laboratory of Applied Atomic and Molecular Spectroscopy, Jilin University, Changchun 130012 (China); Feng, Mang, E-mail: mangfeng@wipm.ac.cn [State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071 (China)

2015-10-16

Decoherence of an open quantum system could be universally slowed down via ultra-fast modulation including regular, concatenated, random and even noisy control pulse sequences. We propose two noisy control schemes for a laser-driven qubit in order to suppress the dissipation induced by the environment, where employment of a weak driving laser is to alleviate the requirement for the control pulse strength down to the microwave regime. Calculations and analyses are based on a dynamical decoupling approach governed by the quantum-state-diffusion equation and the standard perturbation theory. The schemes can be applied to various systems, such as the cold atoms and quantum dots, manipulated by lasers for quantum information processing. - Highlights: • Two noisy control schemes for a laser-driven qubit are proposed. • Inspiring dissipation-suppression process is demonstrated both analytically and numerically. • The fidelity improvement is specified for the trapped ion by controlling the key parameters.

Light-field-driven currents in graphene

Science.gov (United States)

Higuchi, Takuya; Heide, Christian; Ullmann, Konrad; Weber, Heiko B.; Hommelhoff, Peter

2017-10-01

The ability to steer electrons using the strong electromagnetic field of light has opened up the possibility of controlling electron dynamics on the sub-femtosecond (less than 10-15 seconds) timescale. In dielectrics and semiconductors, various light-field-driven effects have been explored, including high-harmonic generation, sub-optical-cycle interband population transfer and the non-perturbative change of the transient polarizability. In contrast, much less is known about light-field-driven electron dynamics in narrow-bandgap systems or in conductors, in which screening due to free carriers or light absorption hinders the application of strong optical fields. Graphene is a promising platform with which to achieve light-field-driven control of electrons in a conducting material, because of its broadband and ultrafast optical response, weak screening and high damage threshold. Here we show that a current induced in monolayer graphene by two-cycle laser pulses is sensitive to the electric-field waveform, that is, to the exact shape of the optical carrier field of the pulse, which is controlled by the carrier-envelope phase, with a precision on the attosecond (10-18 seconds) timescale. Such a current, dependent on the carrier-envelope phase, shows a striking reversal of the direction of the current as a function of the driving field amplitude at about two volts per nanometre. This reversal indicates a transition of light-matter interaction from the weak-field (photon-driven) regime to the strong-field (light-field-driven) regime, where the intraband dynamics influence interband transitions. We show that in this strong-field regime the electron dynamics are governed by sub-optical-cycle Landau-Zener-Stückelberg interference, composed of coherent repeated Landau-Zener transitions on the femtosecond timescale. Furthermore, the influence of this sub-optical-cycle interference can be controlled with the laser polarization state. These coherent electron dynamics in

Bunch decompression for laser-plasma driven free-electron laser demonstration schemes

Directory of Open Access Journals (Sweden)

T. Seggebrock

2013-07-01

Full Text Available X-ray free-electron lasers (FELs require a very high electron beam quality in terms of emittance and energy spread. Since 2004 high quality electrons produced by laser-wakefield accelerators have been demonstrated, but the electron quality up to now did not allow the operation of a compact x-ray FEL using these electrons. Maier et al. [Phys. Rev. X 2, 031019 (2012PRXHAE2160-330810.1103/PhysRevX.2.031019] suggested a concept for a proof-of-principle experiment allowing FEL operation in the vacuum ultraviolet range based on an optimized undulator and bunch decompression using electron bunches from a laser-plasma accelerator as currently available. In this paper we discuss in more detail how a chicane can be used as a bunch stretcher instead of a bunch compressor to allow the operation of a laser-wakefield accelerator driven FEL using currently available electrons. A scaling characterizing the impact of bunch decompression on the gain length is derived and the feasibility of the concept is tested numerically in a demanding scenario.

Optical emission from laser-produced chromium and magnesium ...

Indian Academy of Sciences (India)

Abstract. Parametric study of optical emission from two successive laser pulses pro- ... The hot laser-produced plasma radiates various types of emissions ..... lasers. The qualitative agreement of this analysis with our observations confirms.

Periodic thermodynamics of laser-driven molecular motor

International Nuclear Information System (INIS)

Li Dan; Zheng Wenwei; Wang Zhisong

2008-01-01

Operation of a laser-driven nano-motor inevitably generates a non-trivial amount of heat, which can possibly lead to instability or even hinder the motor's continual running. This work quantitatively examines the overheating problem for a recently proposed laser-operated molecular locomotive. We present a single-molecule cooling theory, in which molecular details of the locomotive system are explicitly treated. This theory is able to quantitatively predict cooling efficiency for various candidates of molecular systems for the locomotive, and also suggests concrete strategies for improving the locomotive's cooling. It is found that water environment is able to cool the hot locomotive down to room temperature within 100 picoseconds after photon absorption. This cooling time is a few orders of magnitude shorter than the typical time for laser operation, effectively preventing any overheating for the nano-locomotive. However, when the cooling is less effective in non-aqueous environment, residual heat may build up. A continuous running of the motor will then lead to a periodic thermodynamics, which is a common character of many laser-operated nano-devices

Enhanced laser-energy coupling to dense plasmas driven by recirculating electron currents

Science.gov (United States)

Gray, R. J.; Wilson, R.; King, M.; Williamson, S. D. R.; Dance, R. J.; Armstrong, C.; Brabetz, C.; Wagner, F.; Zielbauer, B.; Bagnoud, V.; Neely, D.; McKenna, P.

2018-03-01

The absorption of laser energy and dynamics of energetic electrons in dense plasma is fundamental to a range of intense laser-driven particle and radiation generation mechanisms. We measure the total reflected and scattered laser energy as a function of intensity, distinguishing between the influence of pulse energy and focal spot size on total energy absorption, in the interaction with thin foils. We confirm a previously published scaling of absorption with intensity by variation of laser pulse energy, but find a slower scaling when changing the focal spot size. 2D particle-in-cell simulations show that the measured differences arise due to energetic electrons recirculating within the target and undergoing multiple interactions with the laser pulse, which enhances absorption in the case of large focal spots. This effect is also shown to be dependent on the laser pulse duration, the target thickness and the electron beam divergence. The parameter space over which this absorption enhancement occurs is explored via an analytical model. The results impact our understanding of the fundamental physics of laser energy absorption in solids and thus the development of particle and radiation sources driven by intense laser–solid interactions.

Radiation reaction effect on laser driven auto-resonant particle acceleration

International Nuclear Information System (INIS)

Sagar, Vikram; Sengupta, Sudip; Kaw, P. K.

2015-01-01

The effects of radiation reaction force on laser driven auto-resonant particle acceleration scheme are studied using Landau-Lifshitz equation of motion. These studies are carried out for both linear and circularly polarized laser fields in the presence of static axial magnetic field. From the parametric study, a radiation reaction dominated region has been identified in which the particle dynamics is greatly effected by this force. In the radiation reaction dominated region, the two significant effects on particle dynamics are seen, viz., (1) saturation in energy gain by the initially resonant particle and (2) net energy gain by an initially non-resonant particle which is caused due to resonance broadening. It has been further shown that with the relaxation of resonance condition and with optimum choice of parameters, this scheme may become competitive with the other present-day laser driven particle acceleration schemes. The quantum corrections to the Landau-Lifshitz equation of motion have also been taken into account. The difference in the energy gain estimates of the particle by the quantum corrected and classical Landau-Lifshitz equation is found to be insignificant for the present day as well as upcoming laser facilities

Laser driven single shock compression of fluid deuterium from 45 to 220 GPa

Energy Technology Data Exchange (ETDEWEB)

Hicks, D; Boehly, T; Celliers, P; Eggert, J; Moon, S; Meyerhofer, D; Collins, G

2008-03-23

The compression {eta} of liquid deuterium between 45 and 220 GPa under laser-driven shock loading has been measured using impedance matching to an aluminum (Al) standard. An Al impedance match model derived from a best fit to absolute Hugoniot data has been used to quantify and minimize the systematic errors caused by uncertainties in the high-pressure Al equation of state. In deuterium below 100 GPa results show that {eta} {approx_equal} 4.2, in agreement with previous impedance match data from magnetically-driven flyer and convergent-explosive shock wave experiments; between 100 and 220 GPa {eta} reaches a maximum of {approx}5.0, less than the 6-fold compression observed on the earliest laser-shock experiments but greater than expected from simple extrapolations of lower pressure data. Previous laser-driven double-shock results are found to be in good agreement with these single-shock measurements over the entire range under study. Both sets of laser-shock data indicate that deuterium undergoes an abrupt increase in compression at around 110 GPa.

Laser startup optics for Baseball II and future mirror machines

International Nuclear Information System (INIS)

Frank, A.M.; Chargin, A.K.; Brown, N.J.

1975-01-01

The laser startup system for Baseball II-T uses a 300-J CO 2 laser to hit a 100-μ diameter pellet with a laser power density on the order of 10 13 W/cm 2 . The laser is a 20-cm diameter unstable resonator transversely excited (TEA) oscillator. The beam is split and then focused using off-axis parabolas. The symmetric configuration and central obscuration of the CO 2 beam allow coaxial alignment and pellet detection optics. This experiment primarily uses commercially available systems and components. Optical elements were fabricated both by direct machining and standard polishing techniques. The laser and optical systems are directly scalable to reactor requirements using demonstrated technologies

Construction and characterization of a laser-driven proton beamline at GSI

Energy Technology Data Exchange (ETDEWEB)

Busold, Simon

2014-05-15

The thesis includes the first experiments with the new 100 TW laser beamline of the PHELIX laser facility at GSI Darmstadt to drive a TNSA (Target Normal Sheath Acceleration) proton source at GSI's Z6 experimental area. At consecutive stages a pulsed solenoid has been applied for beam transport and energy selection via chromatic focusing, as well as a radiofrequency cavity for energy compression of the bunch. This novel laser-driven proton beamline, representing a central experiment of the German national LIGHT collaboration (Laser Ion Generation, Handling and Transport), has been used to create collimated, intense proton bunches at 10 MeV with 2.7% energy spread from the laser-driven source. Also, the feasibility of phase focusing experiments with this setup has been shown and simulations predict peak currents of 10{sup 10} protons/ns at this energy level. Furthermore, first quantitative measurements on the spectral properties of the also present co-moving electrons from such a proton source could be performed and their influence on the protons within the solenoid observed. Finally, permanent magnetic quadrupoles as an alternative first ion collimation system have been investigated experimentally.

Proceedings of the conference on lasers and electro-optics

International Nuclear Information System (INIS)

Anon.

1988-01-01

This book presents the papers discussed at a conference on the subject of electro-optics and lasers. Some of the topics discussed were: laser fusion and interactions; implosion experiments; tunable integrated Bragg lasers, CO 2 lasers; present status of integrated lasers; DFB lasers; transition metal lasers-solid state lasers, mirror laser resonators, multiquantumwell lasers; fusion laser technology; and dynamics and characteristics of diode lasers

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.

Dynamics of a multiple-pulse-driven x-ray laser plasma

International Nuclear Information System (INIS)

Wan, A.S.; Da Silva, L.B.; Moreno, J.C.; Cauble, R.; Celliers, P.; Dalhed, H.E. Jr.; Koch, J.A.; Nilsen, J.

1996-01-01

In this paper we describe experimental and computational studies of multiple-pulse-driven laser plasma, which is the gain medium for a neon-like yttrium x-ray laser. Near-field emission profiles have been measured both with and without reinjection of the x-ray laser photons to couple with the amplifying medium created by later pulses using an external multilayer mirror. From the temporal and spatial evolution of the near-field emission profiles we can examine the pulse-to-pulse variation of the x-ray laser plasma due to changes in the hydrodynamics, laser deposition, and the injecting of x-ray laser photons back into an amplifying x-ray laser plasma. Using a combination of radiation hydrodynamics, atomic kinetics, and ray propagation codes, reasonable agreement has been obtained between simulations and the experimental results. copyright 1996 American Institute of Physics

Effect of External Optical Feedback for Nano-laser Structures

DEFF Research Database (Denmark)

Taghizadeh, Alireza; Mørk, Jesper; Chung, Il-Sug

2013-01-01

We theoretically investigated the effect of optical feedback on a photonic crystal nanolaser, comparing with conventional in-plane and vertical-cavity lasers.......We theoretically investigated the effect of optical feedback on a photonic crystal nanolaser, comparing with conventional in-plane and vertical-cavity lasers....

Time-resolved analysis of nonlinear optical limiting for laser synthesized carbon nanoparticles

Science.gov (United States)

Chen, G. X.; Hong, M. H.

2010-11-01

Nonlinear optical limiting materials have attracted much research interest in recent years. Carbon nanoparticles suspended in liquids show a strong nonlinear optical limiting function. It is important to investigate the nonlinear optical limiting process of carbon nanoparticles for further improving their nonlinear optical limiting performance. In this study, carbon nanoparticles were prepared by laser ablation of a carbon target in tetrahydrofuran (THF). Optical limiting properties of the samples were studied with 532-nm laser light, which is in the most sensitive wavelength band for human eyes. The shape of the laser pulse plays an important role for initializing the nonlinear optical limiting effect. Time-resolved analysis of laser pulses discovered 3 fluence stages of optical limiting. Theoretical simulation indicates that the optical limiting is initialized by a near-field optical enhancement effect.

Sol-gel optical coatings for lasers: Part 1

International Nuclear Information System (INIS)

Floch, H.G.; Belleville, P.F.; Priotton, J.J.

1995-01-01

Many manufacturers and users claim that optical coatings are best prepared by physical vapor deposition technology. Others believe that sol-gel technology is an effective and competitive alternative. This article, the first of three, emphasizes sol-gel thin-film history and relates it to high-power laser technology, chemistry of the sol-gel process, production of optical coatings and deposition techniques. The second and third articles describe the preparation and performance of antireflective and highly reflective sol-gel optical coatings, respectively, that have been developed for the 1.8-MJ/500-TW (351-nm) pulsed neodymium-glass laser. This powerful laser is to be used in France's Inertial Confinement Fusion (ICF) program. It will demonstrate, at the laboratory scale, ignition of deuterium-tritium fusion fuel

Fusion Yield Enhancement in Magnetized Laser-Driven Implosions

International Nuclear Information System (INIS)

Chang, P. Y.; Fiksel, G.; Hohenberger, M.; Knauer, J. P.; Marshall, F. J.; Betti, R.; Meyerhofer, D. D.; Seguin, F. H.; Petrasso, R. D.

2011-01-01

Enhancement of the ion temperature and fusion yield has been observed in magnetized laser-driven inertial confinement fusion implosions on the OMEGA Laser Facility. A spherical CH target with a 10 atm D 2 gas fill was imploded in a polar-drive configuration. A magnetic field of 80 kG was embedded in the target and was subsequently trapped and compressed by the imploding conductive plasma. As a result of the hot-spot magnetization, the electron radial heat losses were suppressed and the observed ion temperature and neutron yield were enhanced by 15% and 30%, respectively.

Optical vortex generation from a diode-pumped alexandrite laser

Science.gov (United States)

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

2018-04-01

We present the demonstration of an optical vortex mode directly generated from a diode-pumped alexandrite slab laser, operating in the bounce geometry. This is the first demonstration of an optical vortex mode generated from an alexandrite laser or from any other vibronic laser. An output power of 2 W for a vortex mode with a ‘topological charge’ of 1 was achieved and the laser was made to oscillate with both left- and right-handed vorticity. The laser operated at two distinct wavelengths simultaneously, 755 and 759 nm, due to birefringent filtering in the alexandrite gain medium. The result offers the prospect of broadly wavelength tunable vortex generation directly from a laser.

Laser driven shock wave experiments for equation of state studies at megabar pressures

CERN Document Server

Pant, H C; Senecha, V K; Bandyopadhyay, S; Rai, V N; Khare, P; Bhat, R K; Gupta, N K; Godwal, B K

2002-01-01

We present the results from laser driven shock wave experiments for equation of state (EOS) studies of gold metal. An Nd:YAG laser chain (2 J, 1.06 mu m wavelength, 200 ps pulse FWHM) is used to generate shocks in planar Al foils and Al + Au layered targets. The EOS of gold in the pressure range of 9-13 Mbar is obtained using the impedance matching technique. The numerical simulations performed using the one-dimensional radiation hydrodynamic code support the experimental results. The present experimental data show remarkable agreement with the existing standard EOS models and with other experimental data obtained independently using laser driven shock wave experiments.

Laser driven shock wave experiments for equation of state studies at megabar pressures

International Nuclear Information System (INIS)

Pant, H C; Shukla, M; Senecha, V K; Bandyopadhyay, S; Rai, V N; Khare, P; Bhat, R K; Gupta, N K; Godwal, B K

2002-01-01

We present the results from laser driven shock wave experiments for equation of state (EOS) studies of gold metal. An Nd:YAG laser chain (2 J, 1.06 μm wavelength, 200 ps pulse FWHM) is used to generate shocks in planar Al foils and Al + Au layered targets. The EOS of gold in the pressure range of 9-13 Mbar is obtained using the impedance matching technique. The numerical simulations performed using the one-dimensional radiation hydrodynamic code support the experimental results. The present experimental data show remarkable agreement with the existing standard EOS models and with other experimental data obtained independently using laser driven shock wave experiments

Optical emission from laser-produced chromium and magnesium

Indian Academy of Sciences (India)

Optical emission from laser-produced chromium and magnesium plasma under the effect of two sequential laser pulses ... Laser Plasma Division, Centre for Advanced Technology, Indore 452 013, India; Diagnostic Instrumentation and Analysis Laboratory, Mississippi State University, 205 Research Boulevard, Starkville, ...

Advanced approaches to high intensity laser-driven ion acceleration

International Nuclear Information System (INIS)

Henig, Andreas

2010-01-01

Since the pioneering work that was carried out 10 years ago, the generation of highly energetic ion beams from laser-plasma interactions has been investigated in much detail in the regime of target normal sheath acceleration (TNSA). Creation of ion beams with small longitudinal and transverse emittance and energies extending up to tens of MeV fueled visions of compact, laser-driven ion sources for applications such as ion beam therapy of tumors or fast ignition inertial con finement fusion. However, new pathways are of crucial importance to push the current limits of laser-generated ion beams further towards parameters necessary for those applications. The presented PhD work was intended to develop and explore advanced approaches to high intensity laser-driven ion acceleration that reach beyond TNSA. In this spirit, ion acceleration from two novel target systems was investigated, namely mass-limited microspheres and nm-thin, free-standing diamond-like carbon (DLC) foils. Using such ultrathin foils, a new regime of ion acceleration was found where the laser transfers energy to all electrons located within the focal volume. While for TNSA the accelerating electric field is stationary and ion acceleration is spatially separated from laser absorption into electrons, now a localized longitudinal field enhancement is present that co-propagates with the ions as the accompanying laser pulse pushes the electrons forward. Unprecedented maximum ion energies were obtained, reaching beyond 0.5 GeV for carbon C 6+ and thus exceeding previous TNSA results by about one order of magnitude. When changing the laser polarization to circular, electron heating and expansion were shown to be efficiently suppressed, resulting for the first time in a phase-stable acceleration that is dominated by the laser radiation pressure which led to the observation of a peaked C 6+ spectrum. Compared to quasi-monoenergetic ion beam generation within the TNSA regime, a more than 40 times increase in

Advanced approaches to high intensity laser-driven ion acceleration

Energy Technology Data Exchange (ETDEWEB)

Henig, Andreas

2010-04-26

Since the pioneering work that was carried out 10 years ago, the generation of highly energetic ion beams from laser-plasma interactions has been investigated in much detail in the regime of target normal sheath acceleration (TNSA). Creation of ion beams with small longitudinal and transverse emittance and energies extending up to tens of MeV fueled visions of compact, laser-driven ion sources for applications such as ion beam therapy of tumors or fast ignition inertial con finement fusion. However, new pathways are of crucial importance to push the current limits of laser-generated ion beams further towards parameters necessary for those applications. The presented PhD work was intended to develop and explore advanced approaches to high intensity laser-driven ion acceleration that reach beyond TNSA. In this spirit, ion acceleration from two novel target systems was investigated, namely mass-limited microspheres and nm-thin, free-standing diamond-like carbon (DLC) foils. Using such ultrathin foils, a new regime of ion acceleration was found where the laser transfers energy to all electrons located within the focal volume. While for TNSA the accelerating electric field is stationary and ion acceleration is spatially separated from laser absorption into electrons, now a localized longitudinal field enhancement is present that co-propagates with the ions as the accompanying laser pulse pushes the electrons forward. Unprecedented maximum ion energies were obtained, reaching beyond 0.5 GeV for carbon C{sup 6+} and thus exceeding previous TNSA results by about one order of magnitude. When changing the laser polarization to circular, electron heating and expansion were shown to be efficiently suppressed, resulting for the first time in a phase-stable acceleration that is dominated by the laser radiation pressure which led to the observation of a peaked C{sup 6+} spectrum. Compared to quasi-monoenergetic ion beam generation within the TNSA regime, a more than 40 times

Emittance growth in laser-driven RF electron guns

International Nuclear Information System (INIS)

Kim, K.J.

1989-01-01

A simple analysis for the evolution of the electron-beam phase space distribution in laser-driven rf guns is presented. In particular, formulas are derived for the transverse and longitudinal emittances at the exit of the gun. The results are compared and found to agree well with those from simulation. (Author). 9 refs.; 4 figs

Photonic Crystal Laser-Driven Accelerator Structures

International Nuclear Information System (INIS)

Cowan, B

2004-01-01

The authors discuss simulated photonic crystal structure designs for laser-driven particle acceleration. They focus on three-dimensional planar structures based on the so-called ''woodpile'' lattice, demonstrating guiding of a speed-of-light accelerating mode by a defect in the photonic crystal lattice. They introduce a candidate geometry and discuss the properties of the accelerating mode. They also discuss the linear beam dynamics in the structure present a novelmethod for focusing the beam. In addition they describe ongoing investigations of photonic crystal fiber-based structures

Fiber-optical switch using cam-micromotor driven by scratch drive actuators

Science.gov (United States)

Kanamori, Y.; Aoki, Y.; Sasaki, M.; Hosoya, H.; Wada, A.; Hane, K.

2005-01-01

We fabricated a 1 × 1 fiber-optic switch using a cam-micromotor driven by scratch drive actuators (SDAs). Using the cam-micromotor, mechanical translation and precise positioning of an optical fiber were performed. An optical fiber of diameter 50 µm was bent and pushed out with a cam-mechanism driven by the SDAs fabricated by surface micromachining. The maximum rotation speed of the cam-micromotor was 7.5 rpm at a driving frequency of 1.5 kHz. The transient time of the switch to attenuate coupling efficiency less than -40 dB was around 10 ms.

Construction and characterization of a laser-driven proton beamline at GSI

OpenAIRE

Busold, Simon

2014-01-01

The thesis includes the first experiments with the new 100 TW laser beamline of the PHELIX laser facility at GSI Darmstadt to drive a TNSA (Target Normal Sheath Acceleration) proton source at GSI's Z6 experimental area. At consecutive stages a pulsed solenoid has been applied for beam transport and energy selection via chromatic focusing, as well as a radiofrequency cavity for energy compression of the bunch. This novel laser-driven proton beamline, representing a central experiment of the...

Interband optical pulse injection locking of quantum dot mode-locked semiconductor laser.

Science.gov (United States)

Kim, Jimyung; Delfyett, Peter J

2008-07-21

We experimentally demonstrate optical clock recovery from quantum dot mode-locked semiconductor lasers by interband optical pulse injection locking. The passively mode-locked slave laser oscillating on the ground state or the first excited state transition is locked through the injection of optical pulses generated via the opposite transition bands, i.e. the first excited state or the ground state transition from the hybridly mode-locked master laser, respectively. When an optical pulse train generated via the first excited state from the master laser is injected to the slave laser oscillating via ground state, the slave laser shows an asymmetric locking bandwidth around the nominal repetition rate of the slave laser. In the reverse injection case of, i.e. the ground state (master laser) to the first excited state (slave laser), the slave laser does not lock even though both lasers oscillate at the same cavity frequency. In this case, the slave laser only locks to higher injection rates as compared to its own nominal repetition rate, and also shows a large locking bandwidth of 6.7 MHz.

Optical identification of sea-mines - Gated viewing three-dimensional laser radar

DEFF Research Database (Denmark)

Busck, Jens

2005-01-01

A gated viewing high accuracy mono-static laser radar has been developed for the purpose of improving the optical underwater sea-mine identification handled by the Navy. In the final stage of the sea-mine detection, classification and identification process the Navy applies a remote operated...... vehicle for optical identification of the bottom seamine. The experimental results of the thesis indicate that replacing the conventional optical video and spotlight system applied by the Navy with the gated viewing two- and three-dimensional laser radar can improve the underwater optical sea...... of the short laser pulses (0.5 ns), the high laser pulse repetition rate (32.4 kHz), the fast gating camera (0.2 ns), the short camera delay steps (0.1 ns), the applied optical single mode fiber, and the applied algorithm for three-dimensional imaging. The gated viewing laser radar system configuration...

First Observation of Laser-Driven Acceleration of Relativistic Electrons in a Semi-Infinite Vacuum Space

CERN Document Server

Plettner, Tomas; Colby, Eric R; Cowan, Benjamin; Sears, Chris M S; Siemann, Robert; Smith, Todd I; Spencer, James

2005-01-01

We have observed acceleration of relativistic electrons in vacuum driven by a linearly polarized laser beam incident on a thin gold-coated reflective boundary. The observed energy modulation effect follows all the characteristics expected for linear acceleration caused by a longitudinal electric field. As predicted by the Lawson-Woodward theorem the laser driven modulation only appears in the presence of the boundary. It shows a linear dependence with the strength of the electric field of the laser beam and also it is critically dependent on the laser polarization. Finally, it appears to follow the expected angular dependence of the inverse transition radiation process.

Surface Contaminant Control Technologies to Improve Laser Damage Resistance of Optics

Directory of Open Access Journals (Sweden)

Xiaofeng Cheng

2014-01-01

Full Text Available The large high-power solid lasers, such as the National Ignition Facility (NIF of America and the Shenguang-III (SG-III laser facility of China, can output over 2.1 MJ laser pulse for the inertial confinement fusion (ICF experiments. Because of the enhancement of operating flux and the expansion of laser driver scale, the problem of contamination seriously influences their construction period and operation life. During irradiation by intense laser beams, the contaminants on the metallic surface of beam tubes can be transmitted to the optical surfaces and lead to damage of optical components. For the high-power solid-state laser facilities, contamination control focuses on the slab amplifiers, spatial filters, and final-optical assemblies. In this paper, an effective solution to control contaminations including the whole process of the laser driver is put forward to provide the safe operation of laser facilities, and the detailed technical methods of contamination control such as washing, cleanliness metrology, and cleanliness protecting are also introduced to reduce the probability of laser-induced damage of optics. The experimental results show that the cleanliness level of SG-III laser facility is much better to ensure that the laser facility can safely operate at high energy flux.

2nd Topical Workshop on Laser Technology and Optics Design

CERN Document Server

2013-01-01

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

Towards a novel laser-driven method of exotic nuclei extraction−acceleration for fundamental physics and technology

Energy Technology Data Exchange (ETDEWEB)

Nishiuchi, M., E-mail: sergei@jaea.go.jp; Sakaki, H.; Esirkepov, T. Zh. [Japan Atomic Energy Agency, Kansai Photon Science Institute (Japan); Nishio, K. [Japan Atomic Energy Agency, Advanced Science Research Center (Japan); Pikuz, T. A.; Faenov, A. Ya. [Japan Atomic Energy Agency, Kansai Photon Science Institute (Japan); Skobelev, I. Yu. [Russian Academy of Sciences, Joint Institute for High Temperature (Russian Federation); Orlandi, R. [Japan Atomic Energy Agency, Advanced Science Research Center (Japan); Pirozhkov, A. S.; Sagisaka, A.; Ogura, K.; Kanasaki, M.; Kiriyama, H.; Fukuda, Y. [Japan Atomic Energy Agency, Kansai Photon Science Institute (Japan); Koura, H. [Japan Atomic Energy Agency, Advanced Science Research Center (Japan); Kando, M. [Japan Atomic Energy Agency, Kansai Photon Science Institute (Japan); Yamauchi, T. [Graduate School of Maritime Sciences (Japan); Watanabe, Y. [Kyushu University, Interdisciplinary Graduate School of Engineering Sciences (Japan); Bulanov, S. V., E-mail: svbulanov@gmail.com; Kondo, K. [Japan Atomic Energy Agency, Kansai Photon Science Institute (Japan); and others

2016-04-15

A combination of a petawatt laser and nuclear physics techniques can crucially facilitate the measurement of exotic nuclei properties. With numerical simulations and laser-driven experiments we show prospects for the Laser-driven Exotic Nuclei extraction–acceleration method proposed in [M. Nishiuchi et al., Phys, Plasmas 22, 033107 (2015)]: a femtosecond petawatt laser, irradiating a target bombarded by an external ion beam, extracts from the target and accelerates to few GeV highly charged short-lived heavy exotic nuclei created in the target via nuclear reactions.

Overview of Optical and Thermal Laser-Tissue Interaction and Nomenclature

Science.gov (United States)

Welch, Ashley J.; van Gemert, Martin J. C.

The development of a unified theory for the optical and thermal response of tissue to laser radiation is no longer in its infancy, though it is still not fully developed. This book describes our current understanding of the physical events that can occur when light interacts with tissue, particularly the sequence of formulations that estimate the optical and thermal responses of tissue to laser radiation. This overview is followed by an important chapter that describes the basic interactions of light with tissue. Part I considers basic tissue optics. Tissue is treated as an absorbing and scattering medium and methods are presented for calculating and measuring light propagation, including polarized light. Also, methods for estimating tissue optical properties from measurements of reflection and transmission are discussed. Part II concerns the thermal response of tissue owing to absorbed light, and rate reactions are presented for predicting the extent of laser induced thermal damage. Methods for measuring temperature, thermal properties, rate constants, pulsed ablation and laser tissue interactions are detailed. Part III is devoted to examples that use the theory presented in Parts I and II to analyze various medical applications of lasers. Discussions of Optical Coherence Tomography (OCT), forensic optics, and light stimulation of nerves are also included.

Exploratory laser-driven shock wave studies

International Nuclear Information System (INIS)

Solem, J.C.; Veeser, L.R.

1977-11-01

We show the results of a feasibility study for investigating shock structure and for measuring equation-of-state parameters using high-energy, short-pulse lasers. We discuss the temporal and spatial structure of the luminosity from laser-driven shock unloading in aluminum foils. We demonstrate that shock velocity can be measured by observing the time interval between shock emergence across two thicknesses and show data for shocks of 1.3 and 2.1 Mbar. The fact that we observe shock fronts cleanly breaking through steps as small as 3 μm indicates that the shock front thickness is very small in the few megabar region; this is the first experimental verification that these fronts are not more than a few micrometers thick. We present approximate measurements of free-surface velocity. Finally, we speculate on the use of these techniques to obtain detailed equation-of-state data

The effect of laser ablation parameters on optical limiting properties of silver nanoparticles

Science.gov (United States)

Gursoy, Irmak; Yaglioglu, Halime Gul

2017-09-01

This paper presents the effect of laser ablation parameters on optical limiting properties of silver nanoparticles. The current applications of lasers such as range finding, guidance, detection, illumination and designation have increased the potential of damaging optical imaging systems or eyes temporary or permanently. The applications of lasers introduce risks for sensors or eyes, when laser power is higher than damage threshold of the detection system. There are some ways to protect these systems such as neutral density (nd) filters, shutters, etc. However, these limiters reduce the total amount of light that gets into the system. Also, response time of these limiters may not be fast enough to prevent damage and cause precipitation in performance due to deprivation of transmission or contrast. Therefore, optical limiting filters are needed that is transparent for low laser intensities and limit or block the high laser intensities. Metal nanoparticles are good candidates for such optical limiting filters for ns pulsed lasers or CW lasers due to their high damage thresholds. In this study we investigated the optical limiting performances of silver nanoparticles produced by laser ablation technique. A high purity silver target immersed in pure water was ablated with a Nd:YAG nanosecond laser at 532 nm. The effect of altering laser power and ablation time on laser ablation efficiency of nanoparticles was investigated experimentally and optimum values were specified. Open aperture Zscan experiment was used to investigate the effect of laser ablation parameters on the optical limiting performances of silver nanoparticles in pure water. It was found that longer ablation time decreases the optical limiting threshold. These results are useful for silver nanoparticles solutions to obtain high performance optical limiters.

Optically pumped semiconductor lasers for atomic and molecular physics

Science.gov (United States)

Burd, S.; Leibfried, D.; Wilson, A. C.; Wineland, D. J.

2015-03-01

Experiments in atomic, molecular and optical (AMO) physics rely on lasers at many different wavelengths and with varying requirements on spectral linewidth, power and intensity stability. Optically pumped semiconductor lasers (OPSLs), when combined with nonlinear frequency conversion, can potentially replace many of the laser systems currently in use. We are developing a source for laser cooling and spectroscopy of Mg+ ions at 280 nm, based on a frequency quadrupled OPSL with the gain chip fabricated at the ORC at Tampere Univ. of Technology, Finland. This OPSL system could serve as a prototype for many other sources used in atomic and molecular physics.

A laser pointer driven microheater for precise local heating and conditional gene regulation in vivo. Microheater driven gene regulation in zebrafish

Directory of Open Access Journals (Sweden)

Achermann Marc

2009-12-01

Full Text Available Abstract Background Tissue heating has been employed to study a variety of biological processes, including the study of genes that control embryonic development. Conditional regulation of gene expression is a particularly powerful approach for understanding gene function. One popular method for mis-expressing a gene of interest employs heat-inducible heat shock protein (hsp promoters. Global heat shock of hsp-promoter-containing transgenic animals induces gene expression throughout all tissues, but does not allow for spatial control. Local heating allows for spatial control of hsp-promoter-driven transgenes, but methods for local heating are cumbersome and variably effective. Results We describe a simple, highly controllable, and versatile apparatus for heating biological tissue and other materials on the micron-scale. This microheater employs micron-scale fiber optics and uses an inexpensive laser-pointer as a power source. Optical fibers can be pulled on a standard electrode puller to produce tips of varying sizes that can then be used to reliably heat 20-100 μm targets. We demonstrate precise spatiotemporal control of hsp70l:GFP transgene expression in a variety of tissue types in zebrafish embryos and larvae. We also show how this system can be employed as part of a new method for lineage tracing that would greatly facilitate the study of organogenesis and tissue regulation at any time in the life cycle. Conclusion This versatile and simple local heater has broad utility for the study of gene function and for lineage tracing. This system could be used to control hsp-driven gene expression in any organism simply by bringing the fiber optic tip in contact with the tissue of interest. Beyond these uses for the study of gene function, this device has wide-ranging utility in materials science and could easily be adapted for therapeutic purposes in humans.

Development of laser marking system with electro-optic Q-switch

Energy Technology Data Exchange (ETDEWEB)

Kim, Cheol Jung; Kim, Jeong Moog; Kim, Kwang Suk; Park, Seung Kyu; Baik, Sung Hoon

1995-11-01

We developed a high repetition electro-optic Q switch Nd:YAG laser and scan system for laser marking. We localized the scan mirrors and their mounts. We made the database for the optical properties of commercial flat-field lenses with our optics design software. We fabricated the detailed network between the galvanometer based beam scanning system and the laser generator. To accelerate the commercialization by the joint company, the training and transfer of technology were pursued in the joint participation by company researchers from the early stage. (author). 8 refs., 6 tabs., 27 figs.

Development of laser marking system with electro-optic Q-switch

International Nuclear Information System (INIS)

Kim, Cheol Jung; Kim, Jeong Moog; Kim, Kwang Suk; Park, Seung Kyu; Baik, Sung Hoon.

1995-11-01

We developed a high repetition electro-optic Q switch Nd:YAG laser and scan system for laser marking. We localized the scan mirrors and their mounts. We made the database for the optical properties of commercial flat-field lenses with our optics design software. We fabricated the detailed network between the galvanometer based beam scanning system and the laser generator. To accelerate the commercialization by the joint company, the training and transfer of technology were pursued in the joint participation by company researchers from the early stage. (author). 8 refs., 6 tabs., 27 figs

Laser parameters, focusing optics, and side effects in femtosecond laser corneal surgery

Science.gov (United States)

Plamann, Karsten; Nuzzo, Valeria; Peyrot, Donald A.; Deloison, Florent; Savoldelli, Michèle; Legeais, Jean-Marc

2008-02-01

Nowadays, femtosecond lasers are routinely used in refractive eye surgery. Until recently, commercialised clinical systems were exclusively based on ytterbium or neodymium-doped solid state lasers emitting sub-picosecond pulses at a wavelength of about 1 μm and repetition rates of a few 10 kHz. These systems use pulse energies in the μJ range and focussing optics of NA = 0.3 to 0.5. Recent developments have provided a variety of alternative and equally viable approaches: systems are now available using nJ pulses at high numerical apertures and MHz repetition rates - an approach so far only used for femtosecond cell surgery - and fibre laser technology is now being used for femtosecond laser corneal surgery. Recent research has also provided more insight in side effects occurring in present systems: self focusing phenomena and so far unexplained periodical structures have been observed even at high numerical apertures (NA >> 0.5) and moderate pulse energies. The interaction of femtosecond laser pulses with strongly scattering tissue has been studied in view of extending the application of femtosecond lasers to keratoplasty for opaque corneas and to glaucoma surgery. The use of new laser wavelengths and adaptive optics has been proposed. Despite the reputation of femtosecond surgical systems for their precision, repeatability and the absence of secondary effects or complications, a closer examination reveals the presence of subtle phenomena which merit further investigation. We present three of these phenomena: the influence of optical aberration on the quality of the incision, the occurrence of filamentation effects, and the deposit of microscopic glass fragments when performing penetrating incisions.

Recent progress on laser acceleration research

International Nuclear Information System (INIS)

Nakajima, Kazuhisa; Dewa, Hideki; Hosokai, Tomonao; Kanazawa, Shuhei; Kando, Masaki; Kondoh, Shuji; Kotaki, Hideyuki

2000-01-01

Recently there has been a tremendous experimental progress in ultrahigh field particle acceleration driven by ultraintense laser pulses in plasmas. A design of the laser wakefield accelerators aiming at GeV energy gains is discussed by presenting our recent progress on the laser wakefield acceleration experiments, the developments of high quality electron beam injectors and the capillary plasma waveguide for optical guiding of ultrashort intense laser pulses. (author)

Active Interrogation of Sensitive Nuclear Material Using Laser Driven Neutron Beams

International Nuclear Information System (INIS)

Favalli, Andrea; Roth, Markus

2015-01-01

An investigation of the viability of a laser-driven neutron source for active interrogation is reported. The need is for a fast, movable, operationally safe neutron source which is energy tunable and has high-intensity, directional neutron production. Reasons for the choice of neutrons and lasers are set forth. Results from the interrogation of an enriched U sample are shown.

Laser-driven shock-wave propagation in pure and layered targets

International Nuclear Information System (INIS)

Salzmann, D.; Eliezer, S.; Krumbein, A.D.; Gitter, L.

1983-01-01

The propagation properties of laser-driven shock waves in pure and layered polyethylene and aluminum slab targets are studied for a set of laser intensities and pulse widths. The laser-plasma simulations were carried out by means of our one-dimensional Lagrangian hydrodynamic code. It is shown that the various parts of a laser-driven compression wave undergo different thermodynamic trajectories: The shock front portion is on the Hugoniot curve whereas the rear part is closer to an adiabat. It is found that the shock front is accelerated into the cold material till troughly-equal0.8tau (where tau is the laser pulse width) and only later is a constant velocity propagation attained. The scaling laws obtained for the pressure and temperature of the compression wave in pure targets are in good agreement with those published in other works. In layered targets, high compression and pressure were found to occur at the interface of CH 2 on Al targets due to impedance mismatch but were not found when the layers were reversed. The persistence time of the high pressure on the interface in the CH 2 on Al case is long enough relative to the characteristic times of the plasma to have an appreciable influence on the shock-wave propagation into the aluminum layer. This high pressure and compression on the interface can be optimized by adjusting the CH 2 layer thickness

Optical cell cleaning with NIR femtosecond laser pulses

Science.gov (United States)

Uchugonova, Aisada; Breunig, Hans Georg; Batista, Ana; König, Karsten

2015-03-01

Femtosecond laser microscopes have been used as both micro and nanosurgery tools. The optical knock-out of undesired cells in multiplex cell clusters shall be further reported on in this study. Femtosecond laser-induced cell death is beneficial due to the reduced collateral side effects and therefore can be used to selectively destroy target cells within monolayers, as well as within 3D tissues, all the while preserving cells of interest. This is an important characteristic for the application in stem cell research and cancer treatment. Non-precise damage compromises the viability of neighboring cells by inducing side effects such as stress to the cells surrounding the target due to the changes in the microenvironment, resulting from both the laser and laser-exposed cells. In this study, optimum laser parameters for optical cleaning by isolating single cells and cell colonies are exploited through the use of automated software control. Physiological equilibrium and cellular responses to the laser induced damages are also investigated. Cell death dependence on laser focus, determination and selectivity of intensity/dosage, controllable damage and cell recovery mechanisms are discussed.

The Laser Level as an Optics Laboratory Tool

Science.gov (United States)

Kutzner, Mickey

2013-01-01

For decades now, the laser has been used as a handy device for performing ray traces in geometrical optics demonstrations and laboratories. For many ray- trace applications, I have found the laser level 3 to be even more visually compelling and easy for student use than the laser pointer.

XUV/VUV free-electron laser oscillator

International Nuclear Information System (INIS)

Goldstein, J.C.; Newnam, B.E.; Cooper, R.K.; Comly, J.C. Jr.

1984-04-01

It is shown, from computations based on a detailed theoretical model, that modest improvements in electron beam and optical mirror technologies will enable a free-electron laser, driven by an rf linear accelerator, to operate in the 50 to 200-nm range of optical wavelengths. 10 references

Advanced scheme for high-yield laser driven nuclear reactions

Czech Academy of Sciences Publication Activity Database

Margarone, Daniele; Picciotto, A.; Velyhan, Andriy; Krása, Josef; Kucharik, M.; Mangione, A.; Szydlowsky, A.; Malinowska, A.; Bertuccio, G.; Shi, Y.; Crivellari, M.; Ullschmied, Jiří; Bellutti, P.; Korn, Georg

2015-01-01

Roč. 57, č. 1 (2015), s. 014030 ISSN 0741-3335 R&D Projects: GA MŠk ED1.1.00/02.0061; GA MŠk EE2.3.20.0279 EU Projects: European Commission(XE) 284464 - LASERLAB-EUROPE Grant - others:ELI Beamlines(XE) CZ.1.05/1.1.00/02.0061; LaserZdroj (OP VK 3)(XE) CZ.1.07/2.3.00/20.0279 Institutional research plan: CEZ:AV0Z2043910 Institutional support: RVO:68378271 ; RVO:61389021 Keywords : laser plasma * nuclear reaction * laser fusion Subject RIV: BL - Plasma and Gas Discharge Physics; BH - Optics, Masers, Lasers (UFP-V) Impact factor: 2.404, year: 2015

Diffusion driven optofluidic dye lasers encapsulated into polymer chips

DEFF Research Database (Denmark)

Wienhold, Tobias; Breithaupt, Felix; Vannahme, Christoph

2012-01-01

Lab-on-a-chip systems made of polymers are promising for the integration of active optical elements, enabling e.g. on-chip excitation of fluorescent markers or spectroscopy. In this work we present diffusion operation of tunable optofluidic dye lasers in a polymer foil. We demonstrate that these ......Lab-on-a-chip systems made of polymers are promising for the integration of active optical elements, enabling e.g. on-chip excitation of fluorescent markers or spectroscopy. In this work we present diffusion operation of tunable optofluidic dye lasers in a polymer foil. We demonstrate...... that these first order distributed feedback lasers can be operated for more than 90 min at a pulse repetition rate of 2 Hz without fluidic pumping. Ultra-high output pulse energies of more than 10 μJ and laser thresholds of 2 μJ are achieved for resonator lengths of 3 mm. By introducing comparatively large on......-chip dye solution reservoirs, the required exchange of dye molecules is accomplished solely by diffusion. Polymer chips the size of a microscope cover slip (18 × 18 mm2) were fabricated in batches on a wafer using a commercially available polymer (TOPAS® Cyclic Olefin Copolymer). Thermal imprinting...

Minimally invasive non-thermal laser technology using laser-induced optical breakdown for skin rejuvenation

NARCIS (Netherlands)

Habbema, L.; Verhagen, R.; Van Hal, R.; Liu, Y.; Varghese, B.

2011-01-01

We describe a novel, minimally invasive laser technology for skin rejuvenation by creating isolated microscopic lesions within tissue below the epidermis using laser induced optical breakdown. Using an in-house built prototype device, tightly focused near-infrared laser pulses are used to create

Design and performance of large area monolithic electron guns for the Aurora KrF laser system

International Nuclear Information System (INIS)

Kang, M.; Rosocha, L.A.; Romero, V.O.; Van Haaften, F.W.; Brucker, J.P.

1985-01-01

Aurora is an inertial confinement fusion laser system using optical angular multiplexing and a chain of four cold cathode electron beam driven KrF laser amplifiers to produce 10 to 20 kJ of optical energy

Optical polymers for laser medical applications

Science.gov (United States)

Sultanova, Nina G.; Kasarova, Stefka N.; Nikolov, Ivan D.

2016-01-01

In medicine, optical polymers are used not only in ophthalmology but in many laser surgical, diagnostic and therapeutic systems. The application in lens design is determined by their refractive and dispersive properties in the considered spectral region. We have used different measuring techniques to obtain precise refractometric data in the visible and near-infrared spectral regions. Dispersive, thermal and other important optical characteristics of polymers have been studied. Design of a plastic achromatic objective, used in a surgical stereo-microscope at 1064 nm laser wavelength, is accomplished. Geometrical and wavefront aberrations are calculated. Another example of application of polymers is the designed all-mirror apochromatic micro-lens, intended for superluminescent diode fiber coupling in medical systems.

Propagation of a laser-driven relativistic electron beam inside a solid dielectric.

Science.gov (United States)

Sarkisov, G S; Ivanov, V V; Leblanc, P; Sentoku, Y; Yates, K; Wiewior, P; Chalyy, O; Astanovitskiy, A; Bychenkov, V Yu; Jobe, D; Spielman, R B

2012-09-01

Laser probe diagnostics: shadowgraphy, interferometry, and polarimetry were used for a comprehensive characterization of ionization wave dynamics inside a glass target induced by a laser-driven, relativistic electron beam. Experiments were done using the 50-TW Leopard laser at the University of Nevada, Reno. We show that for a laser flux of ∼2 × 10(18) W/cm2 a hemispherical ionization wave propagates at c/3 for 10 ps and has a smooth electron-density distribution. The maximum free-electron density inside the glass target is ∼2 × 10(19) cm-3, which corresponds to an ionization level of ∼0.1%. Magnetic fields and electric fields do not exceed ∼15 kG and ∼1 MV/cm, respectively. The electron temperature has a hot, ringlike structure with a maximum of ∼0.7 eV. The topology of the interference phase shift shows the signature of the "fountain effect", a narrow electron beam that fans out from the propagation axis and heads back to the target surface. Two-dimensional particle-in-cell (PIC) computer simulations demonstrate radial spreading of fast electrons by self-consistent electrostatic fields driven by laser. The very low ionization observed after the laser heating pulse suggests a fast recombination on the sub-ps time scale.

Precision laser processing for micro electronics and fiber optic manufacturing

Science.gov (United States)

Webb, Andrew; Osborne, Mike; Foster-Turner, Gideon; Dinkel, Duane W.

2008-02-01

The application of laser based materials processing for precision micro scale manufacturing in the electronics and fiber optic industry is becoming increasingly widespread and accepted. This presentation will review latest laser technologies available and discuss the issues to be considered in choosing the most appropriate laser and processing parameters. High repetition rate, short duration pulsed lasers have improved rapidly in recent years in terms of both performance and reliability enabling flexible, cost effective processing of many material types including metal, silicon, plastic, ceramic and glass. Demonstrating the relevance of laser micromachining, application examples where laser processing is in use for production will be presented, including miniaturization of surface mount capacitors by applying a laser technique for demetalization of tracks in the capacitor manufacturing process and high quality laser machining of fiber optics including stripping, cleaving and lensing, resulting in optical quality finishes without the need for traditional polishing. Applications include telecoms, biomedical and sensing. OpTek Systems was formed in 2000 and provide fully integrated systems and sub contract services for laser processes. They are headquartered in the UK and are establishing a presence in North America through a laser processing facility in South Carolina and sales office in the North East.

Optically controlled seeding of Raman forward scattering and injection of electrons in a self-modulated laser-wakefield accelerator

International Nuclear Information System (INIS)

Chen, W.-T.; Chien, T.-Y.; Lee, C.-H.; Lin, J.-Y.; Wang, J.; Chen, S.-Y.

2004-01-01

Optical seeding of plasma waves and the injection of electrons are key issues in self-modulated laser-wakefield accelerators. By implementing a copropagating laser prepulse with proper timing, we are able to control the growth of Raman forward scattering and the production of accelerated electrons. The dependence of the Raman intensity on prepulse timing indicates that the seeding of Raman forward scattering is dominated by the ionization-induced wakefield, and the dependence of the divergence and number of accelerated electrons further reveals that the stimulated Raman backward scattering of the prepulse plays the essential role of injecting hot electrons into the fast plasma wave driven by the main pulse

Optical wave microphone measurement during laser ablation of Si

Energy Technology Data Exchange (ETDEWEB)

Mitsugi, Fumiaki, E-mail: mitsugi@cs.kumamoto-u.ac.jp [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto, 860-8555 (Japan); Ide, Ryota; Ikegami, Tomoaki [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto, 860-8555 (Japan); Nakamiya, Toshiyuki; Sonoda, Yoshito [Graduate School of Industrial Engineering, Tokai University, 9-1-1 Toroku, Kumamoto, 862-8652 (Japan)

2012-10-30

Pulsed laser irradiation is used for surface treatment of a solid and ablation for particle formation in gas, liquid or supercritical phase media. When a pulsed laser is used to irradiate a solid, spatial refractive index variations (including photothermal expansion, shockwaves and particles) occur, which vary depending on the energy density of the pulsed laser. We focused on this phenomenon and applied an unique method for detection of refractive index variation using an optical wave microphone based on Fraunhofer diffraction. In this research, we analyzed the waveforms and frequencies of refractive index variations caused by pulsed laser irradiation of silicon in air and measured with an optical wave microphone.

Mode-Locked Semiconductor Lasers for Optical Communication Systems

DEFF Research Database (Denmark)

Yvind, Kresten; Larsson, David; Oxenløwe, Leif Katsuo

2005-01-01

We present investigations on 10 and 40 GHz monolithic mode-locked lasers for applications in optical communications systems. New all-active lasers with one to three quantum wells have been designed, fabricated and characterized....

Optical design of high power excimer laser system

International Nuclear Information System (INIS)

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

2011-01-01

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

Investigation of the dynamic behavior in materials submitted to sub-picosecond laser driven shock

International Nuclear Information System (INIS)

Cuq-Lelandais, Jean-Paul

2010-01-01

driven shock on micrometric single-crystal metals have been performed by using the CEA-DAM molecular dynamic codes. This method, complementary to continuum models, provides an analysis of the microscopic processes related to damage (ductile pore nucleation and growth). The high strain rates involved, around 10 9 s -1 , allow to approach the inter-atomic theoretical cohesion threshold. By the end, the results obtained in both ultra-short and 2D regimes are of great interest for applications such as the adhesion test of thin coating by laser driven shock (LASAT), open the way to news LASAT extensions. For example, various fields in the industry (optics, electronics...) use micrometric coatings but there are actually few ways to characterize their mechanical properties precisely. The transposition of the LASAT process to the fs regime has been tested on multi-layer solar-cell-like, and has confirmed the possibility to de-bond sub-micrometric layers and determine its adhesion threshold. (author)

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.

Statistical Transmutation in Floquet Driven Optical Lattices.

Science.gov (United States)

Sedrakyan, Tigran A; Galitski, Victor M; Kamenev, Alex

2015-11-06

We show that interacting bosons in a periodically driven two dimensional (2D) optical lattice may effectively exhibit fermionic statistics. The phenomenon is similar to the celebrated Tonks-Girardeau regime in 1D. The Floquet band of a driven lattice develops the moat shape, i.e., a minimum along a closed contour in the Brillouin zone. Such degeneracy of the kinetic energy favors fermionic quasiparticles. The statistical transmutation is achieved by the Chern-Simons flux attachment similar to the fractional quantum Hall case. We show that the velocity distribution of the released bosons is a sensitive probe of the fermionic nature of their stationary Floquet state.

Optical System Design and Integration of the Mercury Laser Altimeter

Science.gov (United States)

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

2005-01-01

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

Research on heightening of performance of optical system for free electron laser

International Nuclear Information System (INIS)

Kumagai, Hiroshi; Kawamura, Yoshiyuki; Toyada, Koichi

1996-01-01

Free electron laser will become in future the center of industrial laser technology as a high efficiency, high power output laser. For the development of free electron laser, the development of the elementary technologies such as accelerator, wiggler, optical system and so on must be carried out. For the stable functioning of free electron laser for long hours, the innovative technical development of the optical technology has been strongly desired. In this research, the development of the method of manufacturing a new high performance, multilayer film reflection mirror and the research on compound optical damage by new high energy photon generation process were advanced. The research on the formation of aluminum oxide thin films by using surface reaction, the development of the technology for forming high accuracy, multi-layer thin films and the evaluation of the optical performance of multi-layer films are reported. The constitution of compound optical damage evaluation system, the calculation of the luminance of high energy photons and the experiment on the generation of photons by a carbon dioxide gas laser are described regarding the compound optical damage research. (K.I.)

Analysis of laser-induced heating in optical neuronal guidance

DEFF Research Database (Denmark)

Ebbesen, Christian L.; Bruus, Henrik

2012-01-01

Recently, it has been shown that it is possible to control the growth direction of neuronal growth cones by stimulation with weak laser light; an effect dubbed optical neuronal guidance. The effect exists for a broad range of laser wavelengths, spot sizes, spot intensities, optical intensity...... profiles and beam modulations, but it is unknown which biophysical mechanisms govern it. Based on thermodynamic modeling and simulation using published experimental parameters as input, we argue that the guidance is linked to heating. Until now, temperature effects due to laser-induced heating...

Convection flows driven by laser heating of a liquid layer

OpenAIRE

Rivière , David; Selva , Bertrand; Chraibi , Hamza; Delabre , Ulysse; Delville , Jean-Pierre

2016-01-01

International audience; When a fluid is heated by the absorption of a continuous laser wave, the fluid density decreases in the heated area. This induces a pressure gradient that generates internal motion of the fluid. Due to mass conservation, convection eddies emerge in the sample. To investigate these laser-driven bulk flows at the microscopic scale, we built a setup to perform temperature measurements with a fluorescent-sensitive dye on the one hand, and measured the flow pattern at diffe...

Electrically driven hybrid Si/III-V Fabry-Pérot lasers based on adiabatic mode transformers.

Science.gov (United States)

Ben Bakir, B; Descos, A; Olivier, N; Bordel, D; Grosse, P; Augendre, E; Fulbert, L; Fedeli, J M

2011-05-23

We report the first demonstration of an electrically driven hybrid silicon/III-V laser based on adiabatic mode transformers. The hybrid structure is formed by two vertically superimposed waveguides separated by a 100-nm-thick SiO2 layer. The top waveguide, fabricated in an InP/InGaAsP-based heterostructure, serves to provide optical gain. The bottom Si-waveguides system, which supports all optical functions, is constituted by two tapered rib-waveguides (mode transformers), two distributed Bragg reflectors (DBRs) and a surface-grating coupler. The supermodes of this hybrid structure are controlled by an appropriate design of the tapers located at the edges of the gain region. In the middle part of the device almost all the field resides in the III-V waveguide so that the optical mode experiences maximal gain, while in regions near the III-V facets, mode transformers ensure an efficient transfer of the power flow towards Si-waveguides. The investigated device operates under quasi-continuous wave regime. The room temperature threshold current is 100 mA, the side-mode suppression ratio is as high as 20 dB, and the fiber-coupled output power is ~7 mW.

Status of optics on the OMEGA laser after 18 months of operation

International Nuclear Information System (INIS)

Rigatti, A.L.; Smith, D.J.

1997-01-01

The 60-beam OMEGA laser has sustained approximately 1000 target shots without significant damage to the optics. Approximately 3000 optics on the OMEGA laser system were closely monitored during their installation, and inspections continue throughout the operation of the system. A review of the condition of these optics at each stage of the laser and a summary of the peak incident fluences are presented. The most severe damage on OMEGA is seen on the input, fused-silica, spatial filter lenses. Since these optics are under vacuum, inspection of damaged lenses occurs on a more frequent cycle to track the growth of the defect and to maintain the system's safety. An optic is replaced well before massive failure is expected to occur. Other optics on the system that exhibit different types of damage are BK-7 spatial filter lenses, focus lenses, and target mirrors. The majority of OMEGA optics are not damaging. These include the polarizers, frequency-conversion crystals, primary pickoff lenses, calorimeters, and liquid-crystal optics. Laser glass and development optics such as distributed phase plates are not covered in this review

Estimating optical feedback from a chalcogenide fiber in mid-infrared quantum cascade lasers

Directory of Open Access Journals (Sweden)

L. Jumpertz

2016-10-01

Full Text Available The amount of optical feedback originating from a chalcogenide fiber used to couple light from a mid-infrared quantum cascade laser is evaluated experimentally. Threshold reduction measurements on the fibered laser, combined with an analytical study of a rate equations model of the laser under optical feedback, allow estimating the feedback strength between 11% and 15% depending on the fiber cleavage quality. While this remains below the frontier of the chaotic regime, it is sufficient to deeply modify the optical spectrum of a quantum cascade laser. Hence for applications such as gas spectroscopy, where the shape of the optical spectrum is of prime importance, the use of mid-infrared optical isolators may be necessary for fibered quantum cascade lasers to be fully exploited.

Development of laser surface cladding through energy transmission over optical fiber

International Nuclear Information System (INIS)

Hirano, Kenji; Morishige, Norio; Irisawa, Toshio

1990-01-01

Much attention has recently been paid to laser cladding techniques as an approach in controlling the composition and structure of the metal surface. If YAG laser is used as the cladding method, the flexibility of laser cladding process increases extremely because YAG laser beam is transmitted through an optical fiber, and enabling cladding on pipes installed in actual plants. So experiments on YAG laser cladding through energy transmission over an optical fiber were performed to prevent stress corrosion cracking in austenitic stainless steel pipes. In order to build a cladding layer, mixed metal powder were pre-placed on the inner surface of the pipe using organic binder and the pre-placed powder beds were melted with YAG laser beam transmitted using an optical fiber. This paper introduces the method of building a cladding layer on pipes in actual nuclear plants. (author)

ELIMED: a new hadron therapy concept based on laser driven ion beams

Science.gov (United States)

Cirrone, Giuseppe A. P.; Margarone, Daniele; Maggiore, Mario; Anzalone, Antonello; Borghesi, Marco; Jia, S. Bijan; Bulanov, Stepan S.; Bulanov, Sergei; Carpinelli, Massimo; Cavallaro, Salvatore; Cutroneo, Mariapompea; Cuttone, Giacomo; Favetta, Marco; Gammino, Santo; Klimo, Ondrej; Manti, Lorenzo; Korn, Georg; La Malfa, Giuseppe; Limpouch, Jiri; Musumarra, Agatino; Petrovic, Ivan; Prokupek, Jan; Psikal, Jan; Ristic-Fira, Aleksandra; Renis, Marcella; Romano, Francesco P.; Romano, Francesco; Schettino, Giuseppe; Schillaci, Francesco; Scuderi, Valentina; Stancampiano, Concetta; Tramontana, Antonella; Ter-Avetisyan, Sargis; Tomasello, Barbara; Torrisi, Lorenzo; Tudisco, Salvo; Velyhan, Andriy

2013-05-01

Laser accelerated proton beams have been proposed to be used in different research fields. A great interest has risen for the potential replacement of conventional accelerating machines with laser-based accelerators, and in particular for the development of new concepts of more compact and cheaper hadrontherapy centers. In this context the ELIMED (ELI MEDical applications) research project has been launched by INFN-LNS and ASCR-FZU researchers within the pan-European ELI-Beamlines facility framework. The ELIMED project aims to demonstrate the potential clinical applicability of optically accelerated proton beams and to realize a laser-accelerated ion transport beamline for multi-disciplinary user applications. In this framework the eye melanoma, as for instance the uveal melanoma normally treated with 62 MeV proton beams produced by standard accelerators, will be considered as a model system to demonstrate the potential clinical use of laser-driven protons in hadrontherapy, especially because of the limited constraints in terms of proton energy and irradiation geometry for this particular tumour treatment. Several challenges, starting from laser-target interaction and beam transport development up to dosimetry and radiobiology, need to be overcome in order to reach the ELIMED final goals. A crucial role will be played by the final design and realization of a transport beamline capable to provide ion beams with proper characteristics in terms of energy spectrum and angular distribution which will allow performing dosimetric tests and biological cell irradiation. A first prototype of the transport beamline has been already designed and other transport elements are under construction in order to perform a first experimental test with the TARANIS laser system by the end of 2013. A wide international collaboration among specialists of different disciplines like Physics, Biology, Chemistry, Medicine and medical doctors coming from Europe, Japan, and the US is growing up

Impact of environmental contamination on laser induced damage of silica optics in Laser MegaJoule

International Nuclear Information System (INIS)

Bien-Aime, K.

2009-11-01

Laser induced damage impact of molecular contamination on fused polished silica samples in a context of high power laser fusion facility, such as Laser MegaJoule (LMJ) has been studied. One of the possible causes of laser induced degradation of optical component is the adsorption of molecular or particular contamination on optical surfaces. In the peculiar case of LMJ, laser irradiation conditions are a fluence of 10 J/cm 2 , a wavelength of 351 nm, a pulse duration of 3 ns for a single shot/days frequency. Critical compounds have been identified thanks to environmental measurements, analysis of material outgassing, and identification of surface contamination in the critical environments. Experiments of controlled contamination involving these compounds have been conducted in order to understand and model mechanisms of laser damage. Various hypotheses are proposed to explain the damage mechanism. (author)

Development and characterization of femtosecond laser driven soft x-ray lasers

International Nuclear Information System (INIS)

Bettaibi, I.

2005-06-01

Coherent soft x-ray sources have an important potential for scientific, medical and industrial applications. The development of high intensity laser systems allowed the realization of new coherent and fast soft x-ray sources like high order harmonic generation and soft x-ray lasers. These sources are compact, cheaper than traditional sources such as synchrotrons, and are thus interesting. This thesis presents the study of a new soft x-ray laser pumped by a femto-second laser beam working at 10 Hz. The circularly polarized ultra intense laser is longitudinally focused in a cell filled with xenon or krypton, to obtain the amplification of two lasing lines at 41.8 nm and 32.8 nm in Pd-like xenon and Ni-like krypton respectively. We carry out an experimental and numerical study of the source to understand the importance of different parameters such as the laser intensity and polarization, the gas pressure and the cell length. We have also spatially and temporally characterized the soft x-ray laser beam. To compensate the refraction of the driving laser we have investigated guiding techniques consisting in creating a plasma channel by electric discharge or using the multiple reflections of the driving laser on the internal walls of the dielectric tubes of sapphire or glass. A spectacular improvement of the source performances has been observed in both cases. Finally, we present a preliminary study on a different x-ray scheme: the inner shell photo pumping of neutral atoms. We have developed an optical system, which should create the appropriate conditions for the realisation of short wavelength x-ray amplifier. (author)

Assessment of laser-induced acceleration effects in optical clearing of in vivo human skin by optical coherence tomography

International Nuclear Information System (INIS)

Zhan, Zhigang; Wei, Huajiang; Jin, Ying

2015-01-01

Laser irradiation is considered to be a promising innovative technology which has been developed in an attempt to increase transdermal drug delivery. In this study, a near-infrared CW diode laser (785 nm) was applied to increase permeability of glycerol solutions in human skin in vivo and improve the optical clearing efficacy. Results show that for both 15%v/v and 30%v/v glycerol, the permeability coefficient increased significantly if the detected area of the skin tissue was treated with laser irradiation before optical clearing agents (OCAs) were applied. This study based on optical coherence tomography imaging technique and optical clearing effect finds laser irradiation a new approach for enhancing the penetration of OCAs and accelerating the rate of transdermal drug delivery. (paper)

Assessment of laser-induced acceleration effects in optical clearing of in vivo human skin by optical coherence tomography

Science.gov (United States)

Zhan, Zhigang; Wei, Huajiang; Jin, Ying

2015-02-01

Laser irradiation is considered to be a promising innovative technology which has been developed in an attempt to increase transdermal drug delivery. In this study, a near-infrared CW diode laser (785 nm) was applied to increase permeability of glycerol solutions in human skin in vivo and improve the optical clearing efficacy. Results show that for both 15%v/v and 30%v/v glycerol, the permeability coefficient increased significantly if the detected area of the skin tissue was treated with laser irradiation before optical clearing agents (OCAs) were applied. This study based on optical coherence tomography imaging technique and optical clearing effect finds laser irradiation a new approach for enhancing the penetration of OCAs and accelerating the rate of transdermal drug delivery.

High coupling efficiency of foam spherical hohlraum driven by 2ω laser light

Science.gov (United States)

Chen, Yao-Hua; Lan, Ke; Zheng, Wanguo; Campbell, E. M.

2018-02-01

The majority of solid state laser facilities built for laser fusion research irradiate targets with third harmonic light (0.35 μm) up-converted from the fundamental Nd wavelength at 1.05 μm. The motivation for this choice of wavelength is improved laser-plasma coupling. Significant disadvantages to this choice of wavelength are the reduced damage threshold of optical components and the efficiency of energy conversion to third harmonic light. Both these issues are significantly improved if second harmonic (0.53 μm) radiation is used, but theory and experiments have shown lower optical to x-ray energy conversion efficiency and increased levels of laser-plasma instabilities, resulting in reduced laser-target coupling. In this letter, we propose to use a 0.53 μm laser for the laser ignition facilities and use a low density foam wall to increase the coupling efficiency from the laser to the capsule and present two-dimensional radiation-hydrodynamic simulations of 0.53 μm laser light irradiating an octahedral-spherical hohlraum with a low density foam wall. The simulations show that the reduced optical depth of the foam wall leads to an increased laser-light conversion into thermal x-rays and about 10% higher radiation flux on the capsule than that achieved with 0.35 μm light irradiating a solid density wall commonly used in laser indirect drive fusion research. The details of the simulations and their implications and suggestions for wavelength scaling coupled with innovative hohlraum designs will be discussed.

High-brightness electron source driven by laser

International Nuclear Information System (INIS)

Zhao Kui; Geng Rongli; Wang Lifang

1996-01-01

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

BRIEF COMMUNICATIONS: Optically pumped ultraviolet BR2 laser

Science.gov (United States)

Kamrukov, A. S.; Kozlov, N. P.; Protasov, Yu S.; Ushmarov, E. Yu

1989-12-01

A report is given of lasing achieved for the first time in optically pumped molecular bromine (D' 3Π2g→A' 3π2u, λL approx 292 nm). It was pumped by thermal vacuum ultraviolet radiation emitted by plasmadynamic discharges of magnetoplasma compressors, formed directly in the laser active medium. An output energy of ~ 1.1 J was obtained per laser pulse of ~ 5-μs duration from a Br2:Ar approx 1:450 active mixture at a pressure of ~ 4 atm. A comparison was made of the experimental output parameters of optically pumped Br2, I2, and XeF (B-X) lasers when their geometries and excitation energies were identical.

Quantitative evaluation of enhanced laser tattoo removal by skin optical clearing

Directory of Open Access Journals (Sweden)

Caihua Liu

2015-05-01

Full Text Available Lasers have been widely used for tattoo removal, but the limited light penetration depth caused by high skin scattering property restricts the therapeutic outcome of deep tattoo. Skin optical clearing method, by introducing optical clearing agent (OCA into skin, has shown some improvement in the effect of laser tattoo removal. In this study, the enhanced laser tattoo removal has been quantitatively assessed. OCA was applied to the skin of tattoo animal model and Q-switched Nd:YAG laser (1064 nm irradiation was used to remove the tattoo. The skin evaluation instrument (Mexameter probe, MPA580 was applied to measure the content of tattoo pigment before and after laser treatment, and then the clearance rate of pigment was calculated. Further, Monte Carlo (MC method was utilized to simulate the effect of skin optical clearing on light transmission in tattoo skin model. By comparing the pigment change of tattoo areas respectively treated with OCA plus laser and single laser, it was found that pigment clearance of the former tattoo area was increased by 1.5-fold. Further, the MC simulation verified that the reduced light scattering in skin could increase the effective dose of luminous flux reaching to the deep tattoo regions. It can be concluded from both experiment and theoretical simulations that skin optical clearing technique could improve the outcome of laser tattoo removal, which should be beneficial for clinical laser tattoo removal and other laser pigment elimination.

Single attosecond pulse generation by using plasmon-driven double optical gating technology in crossed metal nanostructures

Science.gov (United States)

Feng, Liqiang; Liu, Katheryn

2018-05-01

An effective method to obtain the single attosecond pulses (SAPs) by using the multi-cycle plasmon-driven double optical gating (DOG) technology in the specifically designed metal nanostructures has been proposed and investigated. It is found that with the introduction of the crossed metal nanostructures along the driven and the gating polarization directions, not only the harmonic cutoff can be extended, but also the efficient high-order harmonic generation (HHG) at the very highest orders occurs only at one side of the region inside the nanostructure. As a result, a 93 eV supercontinuum with the near stable phase can be found. Further, by properly introducing an ultraviolet (UV) pulse into the driven laser polarization direction (which is defined as the DOG), the harmonic yield can be enhanced by two orders of magnitude in comparison with the singe polarization gating (PG) technology. However, as the polarized angle or the ellipticity of the UV pulse increase, the enhancement of the harmonic yield is slightly reduced. Finally, by superposing the selected harmonics from the DOG scheme, a 30 as SAP with intensity enhancement of two orders of magnitude can be obtained.

Test Port for Fiber-Optic-Coupled Laser Altimeter

Science.gov (United States)

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

2011-01-01

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

Time-Resolved Spectroscopy Diagnostic of Laser-Induced Optical Breakdown

Directory of Open Access Journals (Sweden)

Christian G. Parigger

2010-01-01

Full Text Available Transient laser plasma is generated in laser-induced optical breakdown (LIOB. Here we report experiments conducted with 10.6-micron CO2 laser radiation, and with 1.064-micron fundamental, 0.532-micron frequency-doubled, 0.355-micron frequency-tripled Nd:YAG laser radiation. Characterization of laser induced plasma utilizes laser-induced breakdown spectroscopy (LIBS techniques. Atomic hydrogen Balmer series emissions show electron number density of 1017 cm−3 measured approximately 10 μs and 1 μs after optical breakdown for CO2 and Nd:YAG laser radiation, respectively. Recorded molecular recombination emission spectra of CN and C2 Swan bands indicate an equilibrium temperature in excess of 7000 Kelvin, inferred for these diatomic molecules. Reported are also graphite ablation experiments where we use unfocused laser radiation that is favorable for observation of neutral C3 emission due to reduced C3 cation formation. Our analysis is based on computation of diatomic molecular spectra that includes accurate determination of rotational line strengths, or Hönl-London factors.

Nonlinear Absorption-Gain Response and Population Dynamics in a Laser-Driven Four-Level Dense Atomic System

International Nuclear Information System (INIS)

Li Jiahua; Liu Jibing; Luo Jinming; Xie Xiaotao

2006-01-01

We theoretically investigate the response of nonlinear absorption and population dynamics in optically dense media of four-level atoms driven by a single-mode probe laser, via taking the density-dependent near dipole-dipole (NDD) interactions into consideration. The influence of the NDD effects on the absorption of the probe field and population dynamics is predicted via numerical calculations. It is shown that the NDD effects can reduce gradually to transient absorption with the increase of the strengths of the NDD interactions, and transient amplification can be achieved. In the steady-state limit, the probe field exhibits transparency for strong NDD interactions. Alternatively, the population entirely remains at the ground state due to the NDD effects.

Electronic band-gap modified passive silicon optical modulator at telecommunications wavelengths.

Science.gov (United States)

Zhang, Rui; Yu, Haohai; Zhang, Huaijin; Liu, Xiangdong; Lu, Qingming; Wang, Jiyang

2015-11-13

The silicon optical modulator is considered to be the workhorse of a revolution in communications. In recent years, the capabilities of externally driven active silicon optical modulators have dramatically improved. Self-driven passive modulators, especially passive silicon modulators, possess advantages in compactness, integration, low-cost, etc. Constrained by a large indirect band-gap and sensitivity-related loss, the passive silicon optical modulator is scarce and has been not advancing, especially at telecommunications wavelengths. Here, a passive silicon optical modulator is fabricated by introducing an impurity band in the electronic band-gap, and its nonlinear optics and applications in the telecommunications-wavelength lasers are investigated. The saturable absorption properties at the wavelength of 1.55 μm was measured and indicates that the sample is quite sensitive to light intensity and has negligible absorption loss. With a passive silicon modulator, pulsed lasers were constructed at wavelengths at 1.34 and 1.42 μm. It is concluded that the sensitive self-driven passive silicon optical modulator is a viable candidate for photonics applications out to 2.5 μm.

The development of fluorides for high power laser optics

Science.gov (United States)

Ready, J. F.; Vora, H.

1980-07-01

The laser assisted thermonuclear fusion program has need for improved optical materials with high transmission in the ultraviolet, and with low values of nonlinear index of refraction. Lithium fluoride possesses a combination of optical properties which are of use. Single crystalline LiF is limited by low mechanical strength. The technique of press forging to increase the mechanical strength is investigated. LiF single crystals were press forged over the temperature range 300 - 600 deg C to produce fine grained polycrystalline material. Optical homogenity at 633, stress birefringence, scattering at 633, residual absorption over the spectral range 339 - 3800 nm, and laser damage thresholds for 1 ns, 1064 nm and 700 ps, 266 nm laser pulses are evaluated. Single crystals can be press forged without seriously degrading their optical properties. Yield strength in compression, proportional limit and fracture strength in 3 and 4 point bending, fracture energy, and threshold for microyield are discussed.

X-band rf driven free electron laser driver with optics linearization

Directory of Open Access Journals (Sweden)

Yipeng Sun (孙一鹏

2014-11-01

Full Text Available In this paper, a compact hard X-ray free electron lasers (FEL design is proposed with all X-band rf acceleration and two stage bunch compression. It eliminates the need of a harmonic rf linearization section by employing optics linearization in its first stage bunch compression. Quadrupoles and sextupoles are employed in a bunch compressor one (BC1 design, in such a way that second order longitudinal dispersion of BC1 cancels the second order energy correlation in the electron beam. Start-to-end 6-D simulations are performed with all the collective effects included. Emittance growth in the horizontal plane due to coherent synchrotron radiation is investigated and minimized, to be on a similar level with the successfully operating Linac coherent light source (LCLS. At a FEL radiation wavelength of 0.15 nm, a saturation length of 40 meters can be achieved by employing an undulator with a period of 1.5 cm. Without tapering, a FEL radiation power above 10 GW is achieved with a photon pulse length of 50 fs, which is LCLS-like performance. The overall length of the accelerator plus undulator is around 250 meters which is much shorter than the LCLS length of 1230 meters. That makes it possible to build hard X-ray FEL in a laboratory with limited size.

Ultra high-speed x-ray imaging of laser-driven shock compression using synchrotron light

Science.gov (United States)

Olbinado, Margie P.; Cantelli, Valentina; Mathon, Olivier; Pascarelli, Sakura; Grenzer, Joerg; Pelka, Alexander; Roedel, Melanie; Prencipe, Irene; Laso Garcia, Alejandro; Helbig, Uwe; Kraus, Dominik; Schramm, Ulrich; Cowan, Tom; Scheel, Mario; Pradel, Pierre; De Resseguier, Thibaut; Rack, Alexander

2018-02-01

A high-power, nanosecond pulsed laser impacting the surface of a material can generate an ablation plasma that drives a shock wave into it; while in situ x-ray imaging can provide a time-resolved probe of the shock-induced material behaviour on macroscopic length scales. Here, we report on an investigation into laser-driven shock compression of a polyurethane foam and a graphite rod by means of single-pulse synchrotron x-ray phase-contrast imaging with MHz frame rate. A 6 J, 10 ns pulsed laser was used to generate shock compression. Physical processes governing the laser-induced dynamic response such as elastic compression, compaction, pore collapse, fracture, and fragmentation have been imaged; and the advantage of exploiting the partial spatial coherence of a synchrotron source for studying low-density, carbon-based materials is emphasized. The successful combination of a high-energy laser and ultra high-speed x-ray imaging using synchrotron light demonstrates the potentiality of accessing complementary information from scientific studies of laser-driven shock compression.

Optical properties of a multibarrier structure under intense laser fields

Science.gov (United States)

Ospina, D. A.; Akimov, V.; Mora-Ramos, M. E.; Morales, A. L.; Tulupenko, V.; Duque, C. A.

2015-11-01

Using the diagonalization method and within the effective mass and parabolic band approximations, the energy spectrum and the wave functions are investigated in biased multibarrier structure taking into account the effects of nonresonant intense laser fields. We calculated the optical properties from the susceptibility using a nonperturbative formalism recently reported. We study the changes in the intersubband optical absorption coefficients and refraction index for several values of the dressing laser parameter and for some specific values of the electric field applied along the growth direction of the heterostructure. It is concluded from our study that the peaks in the optical absorption spectrum have redshifts or blueshifts as a function of the laser parameter and the electric field. These parameters could be suitable tools for tuning the electronic and optical properties of the multibarrier structure.

Quasistationary magnetic field generation with a laser-driven capacitor-coil assembly.

Science.gov (United States)

Tikhonchuk, V T; Bailly-Grandvaux, M; Santos, J J; Poyé, A

2017-08-01

Recent experiments are showing possibilities to generate strong magnetic fields on the excess of 500 T with high-energy nanosecond laser pulses in a compact setup of a capacitor connected to a single turn coil. Hot electrons ejected from the capacitor plate (cathode) are collected at the other plate (anode), thus providing the source of a current in the coil. However, the physical processes leading to generation of currents exceeding hundreds of kiloamperes in such a laser-driven diode are not sufficiently understood. Here we present a critical analysis of previous results and propose a self-consistent model for the high current generation in a laser-driven capacitor-coil assembly. It accounts for three major effects controlling the diode current: the space charge neutralization, the plasma magnetization between the capacitor plates, and the Ohmic heating of the external circuit-the coil-shaped connecting wire. The model provides the conditions necessary for transporting strongly super-Alfvenic currents through the diode on the time scale of a few nanoseconds. The model validity is confirmed by a comparison with the available experimental data.

(HEL MRI) 3D Meta Optics for High Energy Lasers

Science.gov (United States)

2016-09-13

optical communication link using orbital angular momentum multiplexing ." Optics express 24, no. 9 (2016): 9794-9805. 3. Li, Yuan, Wenzhe Li, J. Miller, and...Magnusson, R.; Binun, P.; McCormick, K., "Wavelength Selection and Polarization Multiplexing of Blue Laser Diodes," in Photonics Technology Letters, IEEE...spatial multiplexing can take advantage of a non-Gaussian beam profile. If the components are to be used as out-couplers in bulk lasers , the optics

Small Optics Laser Damage Test Procedure

Energy Technology Data Exchange (ETDEWEB)

Wolfe, Justin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-10-19

This specification defines the requirements and procedure for laser damage testing of coatings and bare surfaces designated for small optics in the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL).

Micron-size hydrogen cluster target for laser-driven proton acceleration

Science.gov (United States)

Jinno, S.; Kanasaki, M.; Uno, M.; Matsui, R.; Uesaka, M.; Kishimoto, Y.; Fukuda, Y.

2018-04-01

As a new laser-driven ion acceleration technique, we proposed a way to produce impurity-free, highly reproducible, and robust proton beams exceeding 100 MeV using a Coulomb explosion of micron-size hydrogen clusters. In this study, micron-size hydrogen clusters were generated by expanding the cooled high-pressure hydrogen gas into a vacuum via a conical nozzle connected to a solenoid valve cooled by a mechanical cryostat. The size distributions of the hydrogen clusters were evaluated by measuring the angular distribution of laser light scattered from the clusters. The data were analyzed mathematically based on the Mie scattering theory combined with the Tikhonov regularization method. The maximum size of the hydrogen cluster at 25 K and 6 MPa in the stagnation state was recognized to be 2.15 ± 0.10 μm. The mean cluster size decreased with increasing temperature, and was found to be much larger than that given by Hagena’s formula. This discrepancy suggests that the micron-size hydrogen clusters were formed by the atomization (spallation) of the liquid or supercritical fluid phase of hydrogen. In addition, the density profiles of the gas phase were evaluated for 25 to 80 K at 6 MPa using a Nomarski interferometer. Based on the measurement results and the equation of state for hydrogen, the cluster mass fraction was obtained. 3D particles-in-cell (PIC) simulations concerning the interaction processes of micron-size hydrogen clusters with high power laser pulses predicted the generation of protons exceeding 100 MeV and accelerating in a laser propagation direction via an anisotropic Coulomb explosion mechanism, thus demonstrating a future candidate in laser-driven proton sources for upcoming multi-petawatt lasers.

Emittance Measurements from a Laser Driven Electron Injector

CERN Document Server

Reis, D

2003-01-01

The Gun Test Facility (GTF) at the Stanford Linear Accelerator Center was constructed to develop an appropriate electron beam suitable for driving a short wavelength free electron laser (FEL) such as the proposed Linac Coherent Light Source (LCLS). For operation at a wavelength of 1.5 (angstrom), the LCLS requires an electron injector that can produce an electron beam with approximately 1 pi mm-mrad normalized rms emittance with at least 1 nC of charge in a 10 ps or shorter bunch. The GTF consists of a photocathode rf gun, emittance-compensation solenoid, 3 m linear accelerator (linac), drive laser, and diagnostics to measure the beam. The rf gun is a symmetrized 1.6 cell, s-band high gradient, room temperature, photocathode structure. Simulations show that this gun when driven by a temporally and spatially shaped drive laser, appropriately focused with the solenoid, and further accelerated in linac can produce a beam that meets the LCLS requirements. This thesis describes the initial characterization of the ...

Modeling laser-driven electron acceleration using WARP with Fourier decomposition

Energy Technology Data Exchange (ETDEWEB)

Lee, P., E-mail: patrick.lee@u-psud.fr [LPGP, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay (France); Audet, T.L. [LPGP, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay (France); Lehe, R.; Vay, J.-L. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Maynard, G.; Cros, B. [LPGP, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91405 Orsay (France)

2016-09-01

WARP is used with the recent implementation of the Fourier decomposition algorithm to model laser-driven electron acceleration in plasmas. Simulations were carried out to analyze the experimental results obtained on ionization-induced injection in a gas cell. The simulated results are in good agreement with the experimental ones, confirming the ability of the code to take into account the physics of electron injection and reduce calculation time. We present a detailed analysis of the laser propagation, the plasma wave generation and the electron beam dynamics.

Energy Efficiency of an Intracavity Coupled, Laser-Driven Linear Accelerator Pumped by an External Laser

International Nuclear Information System (INIS)

Neil Na, Y.C.; Siemann, R.H.; SLAC; Byer, R.L.; Stanford U., Phys. Dept.

2005-01-01

We calculate the optimum energy efficiency of a laser-driven linear accelerator by adopting a simple linear model. In the case of single bunch operation, the energy efficiency can be enhanced by incorporating the accelerator into a cavity that is pumped by an external laser. In the case of multiple bunch operation, the intracavity configuration is less advantageous because the strong wakefield generated by the electron beam is also recycled. Finally, the calculation indicates that the luminosity of a linear collider based on such a structure is comparably small if high efficiency is desired

Laser power sources and laser technology for accelerators

International Nuclear Information System (INIS)

Lowenthal, D.

1986-01-01

The requirements on laser power sources for advanced accelerator concepts are formidable. These requirements are driven by the need to deliver 5 TeV particles at luminosities of 10/sup 33/ - 10/sup 34/ cm/sup -2/ sec/sup -1/. Given that optical power can be transferred efficiently to the particles these accelerator parameters translate into single pulse laser output energies of several kilojoules and rep rates of 1-10 kHz. The average laser output power is then 10-20 MW. Larger average powers will be needed if efficient transfer proves not to be possible. A laser plant of this magnitude underscores the importance of high wall plug efficiency and reasonable cost in $/Watt. The interface between the laser output pulse format and the accelerator structure is another area that drives the laser requirements. Laser accelerators break up into two general architectures depending on the strength of the laser coupling. For strong coupling mechanisms, the architecture requires many ''small'' lasers powering the accelerator in a staged arrangement. For the weak coupling mechanisms, the architecture must feature a single large laser system whose power must be transported along the entire accelerator length. Both of these arrangements have demanding optical constraints in terms of phase matching sequential stages, beam combining arrays of laser outputs and optimizing coupling of laser power in a single accelerating stage

Recent progress on the Los Alamos Aurora ICF [inertial confinement fusion] laser system

International Nuclear Information System (INIS)

Rosocha, L.A.; Blair, L.S.

1987-01-01

Aurora is the Los Alamos short-pulse, high-power, krypton-fluoride laser system. It serves as an end-to-end technology demonstration prototype for large-scale ultraviolet laser systems for short wavelength inertial confinement fusion (ICF) investigations. The system is designed to employ optical angular multiplexing and serial amplification by electron-beam-driven KrF laser amplifiers to deliver stacked, 248-nm, 5-ns duration multikilojoule laser pulses to ICF-relevant targets. This paper presents a summary of the Aurora system and a discussion of the progress achieved in the construction and integration of the laser system. We concentrate on the main features of the following major system components: front-end lasers, amplifier train, multiplexer, optical relay train, demultiplexer, and the associated optical alignment system. During the past year, two major construction and integration tasks have been accomplished. The first task is the demonstration of 96-beam multiplexing and amplified energy extraction, as evidenced by the integrated operation of the front end, the multiplexer (12-fold and 8-fold encoders), the optical relay train, and three electron-beam-driven amplifiers. The second task is the assembly and installation of the demultiplexer optical hardware, which consists of over 300 optical components ranging in size from several centimeters square to over a meter square. 13 refs., 13 figs

Development of hybrid organic-inorganic optical coatings to prevent laser damage

International Nuclear Information System (INIS)

Compoint, Francois

2015-01-01

The optical devices (lents, mirrors, portholes...) that are set on the chains of the Laser Megajoule (LMJ) may be damaged by the high energy laser beam especially around the UV wavelength of 351 nm. The damages are micronic craters on the rear of the optics that grows exponentially after each laser shots. The study aims at developing some optical thin coatings on the rear of the optical substrates to prevent the growth of the damage by amortizing the laser shock wave, self-healing the craters that has appeared, or repairing the laser hole after the damage occurs. The thin coatings have been prepared by a sol-gel method by using silica precursor and a polydimethylsiloxane (PDMS) elastomer. The two species reacted together to get a hybrid organic-inorganic Ormosil (organically modified silica) material, by creating a silica network linked to the PDMS species with covalent and hydrogen bounds. The thin layers are obtained from the sol-gel solution by using a dip and spin coating method. The coatings have an excellent optical transmission around the UV (351 nm) wavelength. They also have some self-healing properties by using mechanical (viscoelastic) mechanism and chemical reversible hydrogen bounds action in the materials. The silica-PDMS coatings prove to be resistant to the laser beam at 351 nm, despite some optimizations that still need to be done to reach the sought laser damage threshold. (author) [fr

Long-Range Coulomb Effect in Intense Laser-Driven Photoelectron Dynamics.

Science.gov (United States)

Quan, Wei; Hao, XiaoLei; Chen, YongJu; Yu, ShaoGang; Xu, SongPo; Wang, YanLan; Sun, RenPing; Lai, XuanYang; Wu, ChengYin; Gong, QiHuang; He, XianTu; Liu, XiaoJun; Chen, Jing

2016-06-03

In strong field atomic physics community, long-range Coulomb interaction has for a long time been overlooked and its significant role in intense laser-driven photoelectron dynamics eluded experimental observations. Here we report an experimental investigation of the effect of long-range Coulomb potential on the dynamics of near-zero-momentum photoelectrons produced in photo-ionization process of noble gas atoms in intense midinfrared laser pulses. By exploring the dependence of photoelectron distributions near zero momentum on laser intensity and wavelength, we unambiguously demonstrate that the long-range tail of the Coulomb potential (i.e., up to several hundreds atomic units) plays an important role in determining the photoelectron dynamics after the pulse ends.

Structured optical vortices with broadband comb-like optical spectra in Yb:Y3Al5O12/YVO4 Raman microchip laser

Science.gov (United States)

Dong, Jun; Wang, Xiaolei; Zhang, Mingming; Wang, Xiaojie; He, Hongsen

2018-04-01

Structured optical vortices with 4 phase singularities have been generated in a laser diode pumped continuous-wave Yb:Y3Al5O12/YVO4 (Yb:YAG/YVO4) Raman microchip laser. The broadband comb-like first order Stokes laser emitting spectrum including 30 longitudinal modes covers from 1072.49 nm to 1080.13 nm with a bandwidth of 7.64 nm, which is generated with the Raman shift 259 cm-1 of the c-cut YVO4 crystal converted from the fundamental laser around 1.05 μm. Pump power dependent optical vortex beams are attributed to overlap of the Stokes laser field with the fundamental laser field caused by dynamically changing the coupling losses of the fundamental laser field. The maximum output power is 1.16 W, and the optical-to-optical efficiency is 18.4%. This work provides a method for generating structured optical vortices with an optical frequency comb in solid-state Raman microchip lasers, which have potential applications in quantum computations, micro-machining, and information processing.

Return-map for semiconductor lasers with optical feedback

DEFF Research Database (Denmark)

Mørk, Jesper; Tromborg, Bjarne; Sabbatier, H.

1999-01-01

It is well known that a semiconductor laser exposed to moderate optical feedback and biased near threshold exhibits the phenomenon of low-frequency intensity fluctuations (LFF). While this behavior can be numerically simulated using the so-called Lang-Kobayshi model, the interpretation of the phe......It is well known that a semiconductor laser exposed to moderate optical feedback and biased near threshold exhibits the phenomenon of low-frequency intensity fluctuations (LFF). While this behavior can be numerically simulated using the so-called Lang-Kobayshi model, the interpretation...

Skin optical clearing for improvement of laser tattoo removal

Science.gov (United States)

Bashkatov, A. N.; Genina, E. A.; Tuchin, V. V.; Altshuler, G. B.

2009-06-01

The possibility of improvement of laser tattoo removal due to the optical clearing of human skin is investigated. It is shown experimentally that previously perforation of skin stratum corneum allows increasing tattoo image contrast at topical administration of immersion agent in contrast with non-perforated skin. Computer Monte Carlo simulation shows that at the optical clearing of upper skin layers the tattoo image contrast and the photon fraction absorbed in the tattoo area at the depths of 0.5 or 1.0 mm increase, that allows significant decreasing of the power of laser radiation used at laser thermolysis.

CO2 laser pulse switching by optically excited semiconductors

International Nuclear Information System (INIS)

Silva, V.L. da.

1986-01-01

The construction and the study of a semi-conductor optical switch used for generating short infrared pulses and to analyse the semiconductor characteristics, are presented. The switch response time depends on semiconductor and control laser characteristics. The results obtained using a Ge switch controlled by N 2 , NdYag and Dye lasers are presented. The response time was 50 ns limited by Ge recombination time. The reflectivity increased from 7% to 59% using N 2 laser to control the switch. A simple model for semiconductor optical properties that explain very well the experimental results, is also presented. (author) [pt

Miniature shock tube for laser driven shocks.

Science.gov (United States)

Busquet, Michel; Barroso, Patrice; Melse, Thierry; Bauduin, Daniel

2010-02-01

We describe in this paper the design of a miniature shock tube (smaller than 1 cm(3)) that can be placed in a vacuum vessel and allows transverse optical probing and longitudinal backside extreme ultraviolet emission spectroscopy in the 100-500 A range. Typical application is the study of laser launched radiative shocks, in the framework of what is called "laboratory astrophysics."

Nuclear Material Detection by One-Short-Pulse-Laser-Driven Neutron Source

International Nuclear Information System (INIS)

Favalli, Andrea; Aymond, F.; Bridgewater, Jon S.; Croft, Stephen; Deppert, O.; Devlin, Matthew James; Falk, Katerina; Fernandez, Juan Carlos; Gautier, Donald Cort; Gonzales, Manuel A.; Goodsell, Alison Victoria; Guler, Nevzat; Hamilton, Christopher Eric; Hegelich, Bjorn Manuel; Henzlova, Daniela; Ianakiev, Kiril Dimitrov; Iliev, Metodi; Johnson, Randall Philip; Jung, Daniel; Kleinschmidt, Annika; Koehler, Katrina Elizabeth; Pomerantz, Ishay; Roth, Markus; Santi, Peter Angelo; Shimada, Tsutomu; Swinhoe, Martyn Thomas; Taddeucci, Terry Nicholas; Wurden, Glen Anthony; Palaniyappan, Sasikumar; McCary, E.

2015-01-01

Covered in the PowerPoint presentation are the following areas: Motivation and requirements for active interrogation of nuclear material; laser-driven neutron source; neutron diagnostics; active interrogation of nuclear material; and, conclusions, remarks, and future works.

Third-harmonic generation of a laser-driven quantum dot with impurity

Science.gov (United States)

Sakiroglu, S.; Kilic, D. Gul; Yesilgul, U.; Ungan, F.; Kasapoglu, E.; Sari, H.; Sokmen, I.

2018-06-01

The third-harmonic generation (THG) coefficient for a laser-driven quantum dot with an on-center Gaussian impurity under static magnetic field is theoretically investigated. Laser field effect is treated within the high-frequency Floquet approach and the analytical expression of the THG coefficient is deduced from the compact density-matrix approach. The numerical results demonstrate that the application of intense laser field causes substantial changes on the behavior of THG. In addition the position and magnitude of the resonant peak of THG coefficient is significantly affected by the magnetic field, quantum dot size and the characteristic parameters of the impurity potential.

Specification of optical components for a high average-power laser environment

Energy Technology Data Exchange (ETDEWEB)

Taylor, J.R.; Chow, R.; Rinmdahl, K.A.; Willis, J.B.; Wong, J.N.

1997-06-25

Optical component specifications for the high-average-power lasers and transport system used in the Atomic Vapor Laser Isotope Separation (AVLIS) plant must address demanding system performance requirements. The need for high performance optics has to be balanced against the practical desire to reduce the supply risks of cost and schedule. This is addressed in optical system design, careful planning with the optical industry, demonstration of plant quality parts, qualification of optical suppliers and processes, comprehensive procedures for evaluation and test, and a plan for corrective action.

Mathematical model of an optically pumped molecular laser

CSIR Research Space (South Africa)

Botha, LR

2009-07-01

Full Text Available A mathematical model was developed that accurately predicts the performance of an optically pumped HBr laser. Relatively high conversion efficiency was achieved. Tm pumped Ho:YLF is a viable source for pumping HBr laser, while HBr can be scaled...

Acousto-optic laser projection systems for displaying TV information

International Nuclear Information System (INIS)

Gulyaev, Yu V; Kazaryan, M A; Mokrushin, Yu M; Shakin, O V

2015-01-01

This review addresses various approaches to television projection imaging on large screens using lasers. Results are presented of theoretical and experimental studies of an acousto-optic projection system operating on the principle of projecting an image of an entire amplitude-modulated television line in a single laser pulse. We consider characteristic features of image formation in such a system and the requirements for its individual components. Particular attention is paid to nonlinear distortions of the image signal, which show up most severely at low modulation signal frequencies. We discuss the feasibility of improving the process efficiency and image quality using acousto-optic modulators and pulsed lasers. Real-time projectors with pulsed line imaging can be used for controlling high-intensity laser radiation. (review)

Acousto-optic laser projection systems for displaying TV information

Science.gov (United States)

Gulyaev, Yu V.; Kazaryan, M. A.; Mokrushin, Yu M.; Shakin, O. V.

2015-04-01

This review addresses various approaches to television projection imaging on large screens using lasers. Results are presented of theoretical and experimental studies of an acousto-optic projection system operating on the principle of projecting an image of an entire amplitude-modulated television line in a single laser pulse. We consider characteristic features of image formation in such a system and the requirements for its individual components. Particular attention is paid to nonlinear distortions of the image signal, which show up most severely at low modulation signal frequencies. We discuss the feasibility of improving the process efficiency and image quality using acousto-optic modulators and pulsed lasers. Real-time projectors with pulsed line imaging can be used for controlling high-intensity laser radiation.

Acousto-optic laser projection systems for displaying TV information

Energy Technology Data Exchange (ETDEWEB)

Gulyaev, Yu V [V.A.Kotel' nikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Moscow (Russian Federation); Kazaryan, M A [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Mokrushin, Yu M [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (Russian Federation); Shakin, O V [Ioffe Physical Technical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation)

2015-04-30

This review addresses various approaches to television projection imaging on large screens using lasers. Results are presented of theoretical and experimental studies of an acousto-optic projection system operating on the principle of projecting an image of an entire amplitude-modulated television line in a single laser pulse. We consider characteristic features of image formation in such a system and the requirements for its individual components. Particular attention is paid to nonlinear distortions of the image signal, which show up most severely at low modulation signal frequencies. We discuss the feasibility of improving the process efficiency and image quality using acousto-optic modulators and pulsed lasers. Real-time projectors with pulsed line imaging can be used for controlling high-intensity laser radiation. (review)

Route to broadband chaos in a chaotic laser diode subject to optical injection.

Science.gov (United States)

Wang, An-Bang; Wang, Yun-Cai; Wang, Juan-Fen

2009-04-15

We experimentally and numerically demonstrate a route to bandwidth-enhanced chaos that is induced by an additional optical injection for a chaotic laser diode with optical feedback. The measured and calculated optical spectra consistently reveal that the mechanism of bandwidth enhancement is the interaction between the injection and chaotic laser field via beating. The bandwidth can be maximized only when the injected light is detuned into the edge of the optical spectrum of the chaotic laser field and the beating frequency exceeds the original bandwidth. The simulated dynamics maps indicate that 20 GHz broadband chaos can be obtained by commonly used laser diodes.

Deformation Measurement of a Driven Pile Using Distributed Fibre-optic Sensing

Science.gov (United States)

Monsberger, Christoph; Woschitz, Helmut; Hayden, Martin

2016-03-01

New developments in distributed fibre-optic sensing allow the measurement of strain with a very high precision of about 1 µm / m and a spatial resolution of 10 millimetres or even better. Thus, novel applications in several scientific fields may be realised, e. g. in structural monitoring or soil and rock mechanics. Especially due to the embedding capability of fibre-optic sensors, fibre-optic systems provide a valuable extension to classical geodetic measurement methods, which are limited to the surface in most cases. In this paper, we report about the application of an optical backscatter reflectometer for deformation measurements along a driven pile. In general, pile systems are used in civil engineering as an efficient and economic foundation of buildings and other structures. Especially the length of the piles is crucial for the final loading capacity. For optimization purposes, the interaction between the driven pile and the subsurface material is investigated using pile testing methods. In a field trial, we used a distributed fibre-optic sensing system for measuring the strain below the surface of an excavation pit in order to derive completely new information. Prior to the field trial, the fibre-optic sensor was investigated in the laboratory. In addition to the results of these lab studies, we briefly describe the critical process of field installation and show the most significant results from the field trial, where the pile was artificially loaded up to 800 kN. As far as we know, this is the first time that the strain is monitored along a driven pile with such a high spatial resolution.

Ultrafast optical switching in three-dimensional photonic crystals

NARCIS (Netherlands)

Mazurenko, D.A.

2004-01-01

The rapidly expanding research on photonic crystals is driven by potential applications in all-optical switches, optical computers, low-threshold lasers, and holographic data storage. The performance of such devices might surpass the speed of traditional electronics by several orders of magnitude

Wavelength-tunable laser based on nonlinear dispersive-wave generation in a tapered optical waveguide

DEFF Research Database (Denmark)

2015-01-01

The present invention relates to a method and a wavelength tunable laser comprising a first laser source configured to emit a first optical pulse having a pump wavelength, the first optical pulse being emitted in a first longitudinal direction. Furthermore, the wavelength tunable laser comprises...... a waveguide extending in the first longitudinal direction, the waveguide having longitudinally varying phase matching conditions, the waveguide being configured to generate a second optical pulse with a centre wavelength upon receiving the first optical pulse, wherein the wavelength tunable laser...... is configured to tune the centre wavelength of the second optical pulse by varying at least one pulse property of the first optical pulse....

Observation and simulation of an optically driven micromotor

International Nuclear Information System (INIS)

Metzger, N K; Mazilu, M; Dholakia, K; Kelemen, L; Ormos, P

2011-01-01

In the realm of low Reynolds number flow there is a need to find methods to pump, move and mix minute amounts of analyte. Interestingly, micro-devices performing such actuation can be initiated by means of the light–matter interaction. Light induced forces and torques are exerted on such micro-objects, which are then driven by the optical gradient or scattering force. Here, different driving geometries can be realized to harness the light induced force. For example, the scattering force enables micro-gears to be operated in a tangential setup where the micromotor rotors are in line with an optical waveguide. The operational geometry we investigate has the advantage that it reduces the complexity of the driving of such a device in a microfluidic environment by delivering the actuating light by means of a waveguide or fiber optic. In this paper we explore the case of a micromotor being driven by a fiber optically delivered light beam. We experimentally investigate how the driving light interacts with and diffracts from the motor, utilizing two-photon imaging. The micromotor rotation rate dependence on the light field parameters is explored. Additionally, a theoretical model based on the paraxial approximation is used to simulate the torque and predict the rotation rate of such a device and compare it with experiment. The results presented show that our model can be used to optimize the micromotor performance and some example motor designs are evaluated

Observation and simulation of an optically driven micromotor

Science.gov (United States)

Metzger, N. K.; Mazilu, M.; Kelemen, L.; Ormos, P.; Dholakia, K.

2011-04-01

In the realm of low Reynolds number flow there is a need to find methods to pump, move and mix minute amounts of analyte. Interestingly, micro-devices performing such actuation can be initiated by means of the light-matter interaction. Light induced forces and torques are exerted on such micro-objects, which are then driven by the optical gradient or scattering force. Here, different driving geometries can be realized to harness the light induced force. For example, the scattering force enables micro-gears to be operated in a tangential setup where the micromotor rotors are in line with an optical waveguide. The operational geometry we investigate has the advantage that it reduces the complexity of the driving of such a device in a microfluidic environment by delivering the actuating light by means of a waveguide or fiber optic. In this paper we explore the case of a micromotor being driven by a fiber optically delivered light beam. We experimentally investigate how the driving light interacts with and diffracts from the motor, utilizing two-photon imaging. The micromotor rotation rate dependence on the light field parameters is explored. Additionally, a theoretical model based on the paraxial approximation is used to simulate the torque and predict the rotation rate of such a device and compare it with experiment. The results presented show that our model can be used to optimize the micromotor performance and some example motor designs are evaluated.

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

Bandwidth Dependence of Laser Plasma Instabilities Driven by the Nike KrF Laser

Science.gov (United States)

Weaver, J. L.; Oh, J.; Seely, J.; Kehne, D.; Brown, C. M.; Obenschain, S.; Serlin, V.; Schmitt, A. J.; Phillips, L.; Lehmberg, R. H.; McLean, E.; Manka, C.; Feldman, U.

2011-10-01

The Nike krypton-fluoride (KrF) laser at the Naval Research Laboratory operates in the deep UV (248 nm) and employs beam smoothing by induced spatial incoherence (ISI). In the first ISI studies at longer wavelengths (1054 nm and 527 nm) [Obenschain, PRL 62, 768(1989);Mostovych, PRL, 59, 1193(1987); Peyser, Phys. Fluids B 3, 1479(1991)], stimulated Raman scattering, stimulated Brillouin scattering, and the two plasmon decay instability were reduced when wide bandwidth ISI (δν / ν ~ 0.03-0.19%) pulses irradiated targets at moderate to high intensities (1014-1015W/cm2) . Recent Nike work showed that the threshold for quarter critical instabilities increased with the expected wavelength scaling, without accounting for the large bandwidth (δν ~ 1-3 THz). New experiments will compare laser plasma instabilities (LPI) driven by narrower bandwidth pulses to those observed with the standard operation. The bandwidth of KrF lasers can be reduced by adding narrow filters (etalons or gratings) in the initial stages of the laser. This talk will discuss the method used to narrow the output spectrum of Nike, the laser performance for this new operating mode, and target observations of LPI in planar CH targets. Work supported by DoE/NNSA.

Diagnostic measurements related to laser driven inertial confinement fusion

International Nuclear Information System (INIS)

Campbell, D.E.

1979-01-01

Scientists at the Lawrence Livermore Laboratory have been conducting laser driven inertial confinement fusion experiments for over five years. The first proof of the thermonuclear burn came at the Janus target irradiation facility in the spring of 1975. Since that time three succeedingly higher energy facilities have been constructed at Livermore, Cyclops, Argus and Shiva, where increased fusion efficiency has been demonstrated. A new facility, called Nova, is now in the construction phase and we are hopeful that scientific break even (energy released compared to incident laser energy on target) will be demonstrated here in early 1980's. Projected progress of the Livermore program is shown

Noise induced chaos in optically driven colloidal rings.

Science.gov (United States)

Roichman, Yael; Zaslavsky, George; Grier, David G.

2007-03-01

Given a constant flux of energy, many driven dissipative systems rapidly organize themselves into configurations that support steady state motion. Examples include swarming of bacterial colonies, convection in shaken sandpiles, and synchronization in flowing traffic. How simple objects interacting in simple ways self-organize generally is not understood, mainly because so few of the available experimental systems afford the necessary access to their microscopic degrees of freedom. This talk introduces a new class of model driven dissipative systems typified by three colloidal spheres circulating around a ring-like optical trap known as an optical vortex. By controlling the interplay between hydrodynamic interactions and fixed disorder we are able to drive a transition from a previously predicted periodic steady state to fully developed chaos. In addition, by tracking both microscopic trajectories and macroscopic collective fluctuations the relation between the onset of microscopic weak chaos and the evolution of space-time self-similarity in macroscopic transport properties is revealed. In a broader scope, several optical vortices can be coupled to create a large dissipative system where each building block has internal degrees of freedom. In such systems the little understood dynamics of processes like frustration and jamming, fluctuation-dissipation relations and the propagation of collective motion can be tracked microscopically.

Novel target design for enhanced laser driven proton acceleration

Directory of Open Access Journals (Sweden)

Malay Dalui

2017-09-01

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

Aurora multikilojoule KrF laser system prototype for inertial confinement fusion

International Nuclear Information System (INIS)

Rosocha, L.A.; Hanlon, J.A.; Mc Leod, J.; Kang, M.; Kortegaard, B.L.; Burrows, M.D.; Bowling, P.S.

1987-01-01

Aurora is the Los Alamos National Laboratory short-pulse, high-power, KrF laser system. It serves as an end-to-end technology demonstration for large-scale ultraviolet laser systems of interest for short wavelength, inertial confinement fusion (ICF) investigations. The systems is a prototype for using optical angular multiplexing and serial amplification by large electron-beam-driven KrF laser amplifiers to deliver stacked, 248-nm, 5-ns duration multikilojoule laser pulses to ICF targets using an --1-km-long optical beam path. The entire Aurora KrF laser system is described and the design features of the following major system components are summarized: front-end lasers, amplifier train, multiplexer, optical relay train, demultiplexer, target irradiation apparatus, and alignment and controls systems

Optical phase dynamics in mutually coupled diode laser systems exhibiting power synchronization

International Nuclear Information System (INIS)

Pal, Vishwa; Ghosh, R; Prasad, Awadhesh

2011-01-01

We probe the physical mechanism behind the known phenomenon of power synchronization of two diode lasers that are mutually coupled via their delayed optical fields. In a diode laser, the amplitude and the phase of the optical field are coupled by the so-called linewidth enhancement factor, α. In this work, we explore the role of optical phases of the electric fields in amplitude (and hence power) synchronization through α in such mutually delay-coupled diode laser systems. Our numerical results show that the synchronization of optical phases drives the powers of lasers to synchronized death regimes. We also find that as α varies for different diode lasers, the system goes through a sequence of in-phase amplitude-death states. Within the windows between successive amplitude-death regions, the cross-correlation between the field amplitudes exhibits a universal power-law behaviour with respect to α.

Brilliant radiation sources by laser-plasma accelerators and optical undulators

Energy Technology Data Exchange (ETDEWEB)

Debus, Alexander

2012-09-06

This thesis investigates the use of high-power lasers for synchrotron radiation sources with high brilliance, from the EUV to the hard X-ray spectral range. Hereby lasers accelerate electrons by laser-wakefield acceleration (LWFA), act as optical undulators, or both. Experimental evidence shows for the first time that LWFA electron bunches are shorter than the driving laser and have a length scale comparable to the plasma wavelength. Furthermore, a first proof of principle experiment demonstrates that LWFA electrons can be exploited to generate undulator radiation. Building upon these experimental findings, as well as extensive numerical simulations of Thomson scattering, the theoretical foundations of a novel interaction geometry for laser-matter interaction are developed. This new method is very general and when tailored towards relativistically moving targets not being limited by the focusability (Rayleigh length) of the laser, while it does not require a waveguide. In a theoretical investigation of Thomson scattering, the optical analogue of undulator radiation, the limits of Thomson sources in scaling towards higher peak brilliances are highlighted. This leads to a novel method for generating brilliant, highly tunable X-ray sources, which is highly energy efficient by circumventing the laser Rayleigh limit through a novel traveling-wave Thomson scattering (TWTS) geometry. This new method suggests increases in X-ray photon yields of 2-3 orders of magnitudes using existing lasers and a way towards efficient, optical undulators to drive a free-electron laser. The results presented here extend far beyond the scope of this work. The possibility to use lasers as particle accelerators, as well as optical undulators, leads to very compact and energy efficient synchrotron sources. The resulting monoenergetic radiation of high brilliance in a range from extreme ultraviolet (EUV) to hard X-ray radiation is of fundamental importance for basic research, medical

Brilliant radiation sources by laser-plasma accelerators and optical undulators

International Nuclear Information System (INIS)

Debus, Alexander

2012-01-01

This thesis investigates the use of high-power lasers for synchrotron radiation sources with high brilliance, from the EUV to the hard X-ray spectral range. Hereby lasers accelerate electrons by laser-wakefield acceleration (LWFA), act as optical undulators, or both. Experimental evidence shows for the first time that LWFA electron bunches are shorter than the driving laser and have a length scale comparable to the plasma wavelength. Furthermore, a first proof of principle experiment demonstrates that LWFA electrons can be exploited to generate undulator radiation. Building upon these experimental findings, as well as extensive numerical simulations of Thomson scattering, the theoretical foundations of a novel interaction geometry for laser-matter interaction are developed. This new method is very general and when tailored towards relativistically moving targets not being limited by the focusability (Rayleigh length) of the laser, while it does not require a waveguide. In a theoretical investigation of Thomson scattering, the optical analogue of undulator radiation, the limits of Thomson sources in scaling towards higher peak brilliances are highlighted. This leads to a novel method for generating brilliant, highly tunable X-ray sources, which is highly energy efficient by circumventing the laser Rayleigh limit through a novel traveling-wave Thomson scattering (TWTS) geometry. This new method suggests increases in X-ray photon yields of 2-3 orders of magnitudes using existing lasers and a way towards efficient, optical undulators to drive a free-electron laser. The results presented here extend far beyond the scope of this work. The possibility to use lasers as particle accelerators, as well as optical undulators, leads to very compact and energy efficient synchrotron sources. The resulting monoenergetic radiation of high brilliance in a range from extreme ultraviolet (EUV) to hard X-ray radiation is of fundamental importance for basic research, medical

Optical feedback-induced light modulation for fiber-based laser ablation.

Science.gov (United States)

Kang, Hyun Wook

2014-11-01

Optical fibers have been used as a minimally invasive tool in various medical fields. However, due to excessive heat accumulation, the distal end of a fiber often suffers from severe melting or devitrification, leading to the eventual fiber failure during laser treatment. In order to minimize thermal damage at the fiber tip, an optical feedback sensor was developed and tested ex vivo. Porcine kidney tissue was used to evaluate the feasibility of optical feedback in terms of signal activation, ablation performance, and light transmission. Testing various signal thresholds demonstrated that 3 V was relatively appropriate to trigger the feedback sensor and to prevent the fiber deterioration during kidney tissue ablation. Based upon the development of temporal signal signatures, full contact mode rapidly activated the optical feedback sensor possibly due to heat accumulation. Modulated light delivery induced by optical feedback diminished ablation efficiency by 30% in comparison with no feedback case. However, long-term transmission results validated that laser ablation assisted with optical feedback was able to almost consistently sustain light delivery to the tissue as well as ablation efficiency. Therefore, an optical feedback sensor can be a feasible tool to protect optical fiber tips by minimizing debris contamination and delaying thermal damage process and to ensure more efficient and safer laser-induced tissue ablation.

Characterization of collisionally pumped optical-field-ionization soft X-ray lasers

Czech Academy of Sciences Publication Activity Database

Mocek, Tomáš; Sebban, S.; Bettaibi, I.; Upcraft, L. M.; Balcou, P.; Breger, P.; Zeitoun, P.; Le Pape, S.; Ros, D.; Klisnick, A.; Carillon, A.; Jamelot, G.; Rus, Bedřich; Wyart, J. F.

2004-01-01

Roč. 78, - (2004), s. 939-944 ISSN 0946-2171 Grant - others:HPRI(XE) 199900086 Institutional research plan: CEZ:AV0Z1010921 Keywords : X-ray lasers * optical-field-ionization * collisional excitation Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.215, year: 2004

Review on Recent Developments in Laser Driven Inertial Fusion

Directory of Open Access Journals (Sweden)

M. Ghoranneviss

2014-01-01

Full Text Available Discovery of the laser in 1960 hopes were based on using its very high energy concentration within very short pulses of time and very small volumes for energy generation from nuclear fusion as “Inertial Fusion Energy” (IFE, parallel to the efforts to produce energy from “Magnetic Confinement Fusion” (MCF, by burning deuterium-tritium (DT in high temperature plasmas to helium. Over the years the fusion gain was increased by a number of magnitudes and has reached nearly break-even after numerous difficulties in physics and technology had been solved. After briefly summarizing laser driven IFE, we report how the recently developed lasers with pulses of petawatt power and picosecond duration may open new alternatives for IFE with the goal to possibly ignite solid or low compressed DT fuel thereby creating a simplified reactor scheme. Ultrahigh acceleration of plasma blocks after irradiation of picosecond (PS laser pulses of around terawatt (TW power in the range of 1020 cm/s2 was discovered by Sauerbrey (1996 as measured by Doppler effect where the laser intensity was up to about 1018 W/cm2. This is several orders of magnitude higher than acceleration by irradiation based on thermal interaction of lasers has produced.

Conversion from non-orthogonally to orthogonally polarized optical single-sideband modulation using optically injected semiconductor lasers.

Science.gov (United States)

Hung, Yu-Han; Tseng, Chin-Hao; Hwang, Sheng-Kwang

2018-06-01

This Letter investigates an optically injected semiconductor laser for conversion from non-orthogonally to orthogonally polarized optical single-sideband modulation. The underlying mechanism relies solely on nonlinear laser characteristics and, thus, only a typical semiconductor laser is required as the key conversion unit. This conversion can be achieved for a broadly tunable frequency range up to at least 65 GHz. After conversion, the microwave phase quality, including linewidth and phase noise, is mostly preserved, and simultaneous microwave amplification up to 23 dB is feasible.

Applications of lasers and electro-optics

International Nuclear Information System (INIS)

Tan, B.C.; Low, K.S.; Chen, Y.H.; Harith bin Ahmad; Tou, T.Y.

1994-01-01

Supported by the IRPA Programme on Laser Technology and Applications, many types of lasers have been designed, constructed and applied in various areas of science, medicine and industries. Amongst these lasers constructed were high power carbon dioxide lasers, rare gas halide excimer lasers, solid state Neodymium-YAG lasers, nitrogen lasers, flashlamp pumped dye lasers and nitrogen and excimer laser pumped dye lasers. These lasers and the associated electro-optics system, some with computer controlled, are designed and developed for the following areas of applications: 1. Industrial applications of high power carbon dioxide lasers for making of i.c. components and other materials processing purposes. Prototype operational systems have been developed. 2. Medical applications of lasers for cancer treatment using the technique of photodynamic therapy. A new and more effective treatment protocol has been proposed. 3. Agricultural applications of lasers in palm oil and palm fruit-fluorescence diagnostic studies. Fruit ripeness signature has been developed and palm oil oxidation level were investigated. 4. Development of atmospheric pollution monitoring systems using laser lidar techniques. Laboratory scale systems were developed. 5. Other applications of lasers including laser holographic and interferometric methods for the non destructive testing of materials. The activities of the group (from 1988-1990) have resulted in the submission of a patent for a laser device, publication of many research paper sin local and overseas journals and conference proceedings, completion of 1 Ph.D. dissertation and 6 M. Phil theses. Currently (1991), a total of 3 Ph.D., 6 M. Phil research programmes are involved in this research and development programme

Experimental Implementation of a Biometric Laser Synaptic Sensor

Directory of Open Access Journals (Sweden)

Alexander N. Pisarchik

2013-12-01

Full Text Available We fabricate a biometric laser fiber synaptic sensor to transmit information from one neuron cell to the other by an optical way. The optical synapse is constructed on the base of an erbium-doped fiber laser, whose pumped diode current is driven by a pre-synaptic FitzHugh–Nagumo electronic neuron, and the laser output controls a post-synaptic FitzHugh–Nagumo electronic neuron. The implemented laser synapse displays very rich dynamics, including fixed points, periodic orbits with different frequency-locking ratios and chaos. These regimes can be beneficial for efficient biorobotics, where behavioral flexibility subserved by synaptic connectivity is a challenge.

Optical spectroscopy using gas-phase femtosecond laser filamentation.

Science.gov (United States)

Odhner, Johanan; Levis, Robert

2014-01-01

Femtosecond laser filamentation occurs as a dynamic balance between the self-focusing and plasma defocusing of a laser pulse to produce ultrashort radiation as brief as a few optical cycles. This unique source has many properties that make it attractive as a nonlinear optical tool for spectroscopy, such as propagation at high intensities over extended distances, self-shortening, white-light generation, and the formation of an underdense plasma. The plasma channel that constitutes a single filament and whose position in space can be controlled by its input parameters can span meters-long distances, whereas multifilamentation of a laser beam can be sustained up to hundreds of meters in the atmosphere. In this review, we briefly summarize the current understanding and use of laser filaments for spectroscopic investigations of molecules. A theoretical framework of filamentation is presented, along with recent experimental evidence supporting the established understanding of filamentation. Investigations carried out on vibrational and rotational spectroscopy, filament-induced breakdown, fluorescence spectroscopy, and backward lasing are discussed.

A frequency-type optically controllable YAG:Nd(3+) laser

Energy Technology Data Exchange (ETDEWEB)

Baliasnyi, L.M.; Groznov, M.A.; Gubanov, B.S.; Zoria, A.V.; Myl' nikov, V.S.

1990-06-01

The paper demonstrates the feasibility of using MOS-LC modulators based on the s-effect with an internal dividing mirror as the optically controllable mirrors of frequency-type YAG:Nd(3+) lasers. It is shown that the maximum energy of the laser in free-runnig operation of 10 mJ/sq cm is limited by the radiation resistance (not greater than 70 mJ/sq cm) of the orienting fluid, i.e., polyvinyl alcohol. The optical inhomogeneity of the modulator amounts to 20-40 percent, which is connected with the presence of a bonded single-crystal GaAs layer. The working frequency of the laser was about 20 Hz.

Optical nano and micro actuator technology

CERN Document Server

Knopf, George K

2012-01-01

In Optical Nano and Micro Actuator Technology, leading engineers, material scientists, chemists, physicists, laser scientists, and manufacturing specialists offer an in-depth, wide-ranging look at the fundamental and unique characteristics of light-driven optical actuators. They discuss how light can initiate physical movement and control a variety of mechanisms that perform mechanical work at the micro- and nanoscale. The book begins with the scientific background necessary for understanding light-driven systems, discussing the nature of light and the interaction between light and NEMS/MEMS d

Fiber Optic Cables for Transmission of High-Power Laser Pulses in Spaceflight Applications

Science.gov (United States)

Thomes, W. J., Jr.; Ott, M. N.; Chuska, R. F.; Switzer, R. C.; Blair, D. E.

2010-01-01

Lasers with high peak power pulses are commonly used in spaceflight missions for a wide range of applications, from LIDAR systems to optical communications. Due to the high optical power needed, the laser has to be located on the exterior of the satellite or coupled through a series of free space optics. This presents challenges for thermal management, radiation resistance, and mechanical design. Future applications will require multiple lasers located close together, which further complicates the design. Coupling the laser energy into a fiber optic cable allows the laser to be relocated to a more favorable position on the spacecraft. Typical fiber optic termination procedures are not sufficient for injection of these high-power laser pulses without catastrophic damage to the fiber endface. In the current study, we will review the causes of fiber damage during high-power injection and discuss our new manufacturing procedures that overcome these issues to permit fiber use with high reliability in these applications. We will also discuss the proper methods for launching the laser pulses into the fiber to avoid damage and how this is being implemented for current spaceflight missions.

Fiber optic cables for transmission of high-power laser pulses in spaceflight applications

Science.gov (United States)

Thomes, W. J.; Ott, M. N.; Chuska, R. F.; Switzer, R. C.; Blair, D. E.

2017-11-01

Lasers with high peak power pulses are commonly used in spaceflight missions for a wide range of applications, from LIDAR systems to optical communications. Due to the high optical power needed, the laser has to be located on the exterior of the satellite or coupled through a series of free space optics. This presents challenges for thermal management, radiation resistance, and mechanical design. Future applications will require multiple lasers located close together, which further complicates the design. Coupling the laser energy into a fiber optic cable allows the laser to be relocated to a more favorable position on the spacecraft. Typical fiber optic termination procedures are not sufficient for injection of these high-power laser pulses without catastrophic damage to the fiber endface. In the current study, we will review the causes of fiber damage during high-power injection and discuss our new manufacturing procedures that overcome these issues to permit fiber use with high reliability in these applications. We will also discuss the proper methods for launching the laser pulses into the fiber to avoid damage and how this is being implemented for current spaceflight missions.

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.

Design of fiber optic probes for laser light scattering

Science.gov (United States)

Dhadwal, Harbans S.; Chu, Benjamin

1989-01-01

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

Optical spectroscopy of laser-produced plasmas for standoff isotopic analysis

Science.gov (United States)

Harilal, S. S.; Brumfield, B. E.; LaHaye, N. L.; Hartig, K. C.; Phillips, M. C.

2018-06-01

Rapid, in-field, and non-contact isotopic analysis of solid materials is extremely important to a large number of applications, such as nuclear nonproliferation monitoring and forensics, geochemistry, archaeology, and biochemistry. Presently, isotopic measurements for these and many other fields are performed in laboratory settings. Rapid, in-field, and non-contact isotopic analysis of solid material is possible with optical spectroscopy tools when combined with laser ablation. Laser ablation generates a transient vapor of any solid material when a powerful laser interacts with a sample of interest. Analysis of atoms, ions, and molecules in a laser-produced plasma using optical spectroscopy tools can provide isotopic information with the advantages of real-time analysis, standoff capability, and no sample preparation requirement. Both emission and absorption spectroscopy methods can be used for isotopic analysis of solid materials. However, applying optical spectroscopy to the measurement of isotope ratios from solid materials presents numerous challenges. Isotope shifts arise primarily due to variation in nuclear charge distribution caused by different numbers of neutrons, but the small proportional nuclear mass differences between nuclei of various isotopes lead to correspondingly small differences in optical transition wavelengths. Along with this, various line broadening mechanisms in laser-produced plasmas and instrumental broadening generated by the detection system are technical challenges frequently encountered with emission-based optical diagnostics. These challenges can be overcome by measuring the isotope shifts associated with the vibronic emission bands from molecules or by using the techniques of laser-based absorption/fluorescence spectroscopy to marginalize the effect of instrumental broadening. Absorption and fluorescence spectroscopy probe the ground state atoms existing in the plasma when it is cooler, which inherently provides narrower

Efficient optical trapping of CdTe quantum dots by femtosecond laser pulses

KAUST Repository

Chiang, Weiyi

2014-12-11

The development in optical trapping and manipulation has been showing rapid progress, most of it is in the small particle sizes in nanometer scales, substituting the conventional continuous-wave lasers with high-repetition-rate ultrashort laser pulse train and nonlinear optical effects. Here, we evaluate two-photon absorption in optical trapping of 2.7 nm-sized CdTe quantum dots (QDs) with high-repetition-rate femtosecond pulse train by probing laser intensity dependence of both Rayleigh scattering image and the two-photon-induced luminescence spectrum of the optically trapped QDs. The Rayleigh scattering imaging indicates that the two-photon absorption (TPA) process enhances trapping ability of the QDs. Similarly, a nonlinear increase of the two-photon-induced luminescence with the incident laser intensity fairly indicates the existence of the TPA process.

Aircraft Position Measurement Using Laser Beacon Optics.

Science.gov (United States)

1981-01-01

8217Comparison of Solar Concentrators .’ Solar Energy, Vol. 10, p. 93, 1976. 7. Winston , R., ’Light Collection Within the Framework of Goemetrical Optics ...8217 J. Optical Society of Am., Vol. 60, p. 245, 1970. 8. Welford, W. T., tics of Nonimaging Concentrators . New York, Academic Press, T978. 9. Bracewell...helicopter pilot and the flight engineer on board the YO-3A. This thesis will concentrate on the development of the laser beacon, the detector optics

Laser Transmitters for the optical link systems used in CMS

CERN Multimedia

Maximilien Brice

2005-01-01

In the CMS experiment of the now new flagship LHC optical links will be used for the tracker readout system. One part of this components will be semiconductor laser (~50.000 !!!), named correctly: 1310 nm InGaAsP (DCPBH-MQW) edge-emitting laser. They are foreseen as transmitter in the Tx Hybrid part of the optical link system.

All-metal coupling and package of semiconductor laser and amplifier with optical fiber

International Nuclear Information System (INIS)

Xu Fenglan; Li Lina; Zhang Yueqing

1992-01-01

The semiconductor laser and optical amplifier made by Changchun Institute of Physics coupled with optical fiber by use of all-metal coupling are represented. The net gain of semiconductor laser amplifier with optical fiber is 14 ∼18 dB

Development of an energy selector system for laser-driven proton beam applications

Energy Technology Data Exchange (ETDEWEB)

Scuderi, V., E-mail: scuderiv@lns.infn.it [Department of Experimental Program at ELI-Beamlines, Institute of Physics of the ASCR, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic); Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Bijan Jia, S. [Ferdowsi University of Mashhad, Azadi Square, Mashhad (Iran, Islamic Republic of); Carpinelli, M. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Cirrone, G.A.P. [Department of Experimental Program at ELI-Beamlines, Institute of Physics of the ASCR, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic); Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Cuttone, G. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Korn, G. [Department of Experimental Program at ELI-Beamlines, Institute of Physics of the ASCR, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic); Licciardello, T. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Maggiore, M. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, Viale dell' Universit 2, Legnaro (Pd) (Italy); Margarone, D. [Department of Experimental Program at ELI-Beamlines, Institute of Physics of the ASCR, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic); Pisciotta, P.; Romano, F. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Schillaci, F. [Department of Experimental Program at ELI-Beamlines, Institute of Physics of the ASCR, ELI-Beamlines project, Na Slovance 2, Prague (Czech Republic); Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); Stancampiano, C. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Sud, Via Santa Sofia 62, Catania (Italy); and others

2014-03-11

Nowadays, laser-driven proton beams generated by the interaction of high power lasers with solid targets represent a fascinating attraction in the field of the new acceleration techniques. These beams can be potentially accelerated up to hundreds of MeV and, therefore, they can represent a promising opportunity for medical applications. Laser-accelerated proton beams typically show high flux (up to 10{sup 11} particles per bunch), very short temporal profile (ps), broad energy spectra and poor reproducibility. In order to overcome these limitations, these beams have be controlled and transported by means of a proper beam handling system. Furthermore, suitable dosimetric diagnostic systems must be developed and tested. In the framework of the ELIMED project, we started to design a dedicated beam transport line and we have developed a first prototype of a beam line key-element: an Energy Selector System (ESS). It is based on permanent dipoles, capable to control and select in energy laser-accelerated proton beams. Monte Carlo simulations and some preliminary experimental tests have been already performed to characterize the device. A calibration of the ESS system with a conventional proton beam will be performed in September at the LNS in Catania. Moreover, an experimental campaign with laser-driven proton beam at the Centre for Plasma Physics, Queens University in Belfast is already scheduled and will be completed within 2014.

Measuring implosion velocities in experiments and simulations of laser-driven cylindrical implosions on the OMEGA laser

Science.gov (United States)

Hansen, E. C.; Barnak, D. H.; Betti, R.; Campbell, E. M.; Chang, P.-Y.; Davies, J. R.; Glebov, V. Yu; Knauer, J. P.; Peebles, J.; Regan, S. P.; Sefkow, A. B.

2018-05-01

Laser-driven magnetized liner inertial fusion (MagLIF) on OMEGA involves cylindrical implosions, a preheat beam, and an applied magnetic field. Initial experiments excluded the preheat beam and magnetic field to better characterize the implosion. X-ray self-emission as measured by framing cameras was used to determine the shell trajectory. The 1D code LILAC was used to model the central region of the implosion, and results were compared to 2D simulations from the HYDRA code. Post-processing of simulation output with SPECT3D and Yorick produced synthetic x-ray images that were used to compare the simulation results with the x-ray framing camera data. Quantitative analysis shows that higher measured neutron yields correlate with higher implosion velocities. The future goal is to further analyze the x-ray images to characterize the uniformity of the implosions and apply these analysis techniques to integrated laser-driven MagLIF shots to better understand the effects of preheat and the magnetic field.

Computer controlling of writing beam in laser microfabrication of diffractive optics

OpenAIRE

Korolkov, V.; Shimansky, R.; Cherkashin, V.; Denk, D.

2003-01-01

Laser microfabrication of diffractive optics with continuous relief is based on the direct local action of focused laser radiation on the recording material. Control of writing beam parameters (beam power, spot size, waist position) is one of the main tasks in microfabrication using laser writing systems. Method of the control defines the correspondence between the fabricated microrelief of the diffractive optical element and a designed one. Complexity of this task consists in the necessity t...

Developing a more useful surface quality metric for laser optics

Science.gov (United States)

Turchette, Quentin; Turner, Trey

2011-02-01

Light scatter due to surface defects on laser resonator optics produces losses which lower system efficiency and output power. The traditional methodology for surface quality inspection involves visual comparison of a component to scratch and dig (SAD) standards under controlled lighting and viewing conditions. Unfortunately, this process is subjective and operator dependent. Also, there is no clear correlation between inspection results and the actual performance impact of the optic in a laser resonator. As a result, laser manufacturers often overspecify surface quality in order to ensure that optics will not degrade laser performance due to scatter. This can drive up component costs and lengthen lead times. Alternatively, an objective test system for measuring optical scatter from defects can be constructed with a microscope, calibrated lighting, a CCD detector and image processing software. This approach is quantitative, highly repeatable and totally operator independent. Furthermore, it is flexible, allowing the user to set threshold levels as to what will or will not constitute a defect. This paper details how this automated, quantitative type of surface quality measurement can be constructed, and shows how its results correlate against conventional loss measurement techniques such as cavity ringdown times.

Laser-induced optical effects in triglycine-zinc chloride single crystals

International Nuclear Information System (INIS)

Wojciechowski, A.; Kityk, I.V.; Lakshminarayana, G.; Fuks-Janczarek, I.; Berdowski, J.; Berdowska, E.; Tylczynski, Z.

2010-01-01

The influence of irradiation by a cw 532 nm laser on the behavior of the absorption and optical second harmonic generation of triglicyne-zinc chloride crystal has been studied. Additional absorption bands correlate well with the time of the cw laser exposure. These lines occur at 260 nm, 305 nm, and, with small intensity, at 355 nm. The remaining part of the spectra shows substantially less changes. According to the performed quantum chemical simulations, one may expect that the observed dependences and the stability of the observed photoinduced changes are caused by formation of polarized electron-phonon states and the principal role should belong here to the electron-phonon anharmonicities, which cause the effects described by the non-polar third rank polar tensor like optical second harmonic generation. The increasing optical SHG signal shows a clear correlation with the behavior of the green laser-532 nm. It is important principal that for the blue laser-405 nm, the SHG effect is substantially less. This may reflect that the additional absorption maxima may be responsible for the non-linear optical effects. The effect demonstrates a slow time decay.

Laser amplification of optical images using a CW Nd:YAG amplifier

International Nuclear Information System (INIS)

Aman, H

2013-01-01

In this paper a scheme for the amplification of optical images is described, using a continuous wave (CW) diode-pumped Nd:YAG (yttrium aluminum garnet) laser module. A passively q-switched end-pumped Nd:YAG laser is used as a pump source, which carries the optical image distribution as an input which is transmitted towards the amplifier at a distance of about ten feet. For amplification, a three-side-pumped CW Nd:YAG laser module is utilized without the cavity mirrors. In this way, optical images are amplified by a factor of 3.2 and imaged at a distance of ten feet with a spatial resolution of 500 μm. (paper)

Laser beam soldering of micro-optical components

Science.gov (United States)

Eberhardt, R.

2003-05-01

MOTIVATION Ongoing miniaturisation and higher requirements within optical assemblies and the processing of temperature sensitive components demands for innovative selective joining techniques. So far adhesive bonding has primarily been used to assemble and adjust hybrid micro optical systems. However, the properties of the organic polymers used for the adhesives limit the application of these systems. In fields of telecommunication and lithography, an enhancement of existing joining techniques is necessary to improve properties like humidity resistance, laserstability, UV-stability, thermal cycle reliability and life time reliability. Against this background laser beam soldering of optical components is a reasonable joining technology alternative. Properties like: - time and area restricted energy input - energy input can be controlled by the process temperature - direct and indirect heating of the components is possible - no mechanical contact between joining tool and components give good conditions to meet the requirements on a joining technology for sensitive optical components. Additionally to the laser soldering head, for the assembly of optical components it is necessary to include positioning units to adjust the position of the components with high accuracy before joining. Furthermore, suitable measurement methods to characterize the soldered assemblies (for instance in terms of position tolerances) need to be developed.

Laser Communications and Fiber Optics Lab Manual. High-Technology Training Module.

Science.gov (United States)

Biddick, Robert

This laboratory training manual on laser communications and fiber optics may be used in a general technology-communications course for ninth graders. Upon completion of this exercise, students achieve the following goals: match concepts with laser communication system parts; explain advantages of fiber optic cable over conventional copper wire;…

Near-field enhanced optical tweezers utilizing femtosecond-laser nanostructured substrates

Energy Technology Data Exchange (ETDEWEB)

Kotsifaki, D. G., E-mail: dkotsif@eie.gr; Kandyla, M. [Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vasileos Constantinou Avenue, 11635 Athens (Greece); Lagoudakis, P. G. [Department of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ (United Kingdom)

2015-11-23

We present experimental evidence of plasmonic-enhanced optical tweezers, of polystyrene beads in deionized water in the vicinity of metal-coated nanostructures. The optical tweezers operate with a continuous wave near-infrared laser. We employ a Cu/Au bilayer that significantly improves dissipation of heat generated by the trapping laser beam and avoid de-trapping from heat convection currents. We investigate the improvement of the optical trapping force and the effective trapping quality factor, and observe an exponential distance dependence of the trapping force from the nanostructures, indicative of evanescent plasmonic enhancement.

All Solid State Optical Pulse Shaper for the OMEGA Laser Fusion Facility

International Nuclear Information System (INIS)

Okishev, A.V.; Skeldon, M.D.; Keck, R.L.; Seka, W.

2000-01-01

OAK-B135 All Solid State Optical Pulse Shaper for the OMEGA Laser Fusion Facility. The authors have developed an all-solid-state, compact, computer-controlled, flexible optical pulse shaper for the OMEGA laser facility. This pulse shaper produces high bandwidth, temporally shaped laser pulses that meet OMEGA requirements. The design is a significant simplification over existing technology with improved performance capabilities

Solid hydrogen target for laser driven proton acceleration

Science.gov (United States)

Perin, J. P.; Garcia, S.; Chatain, D.; Margarone, D.

2015-05-01

The development of very high power lasers opens up new horizons in various fields, such as laser plasma acceleration in Physics and innovative approaches for proton therapy in Medicine. Laser driven proton acceleration is commonly based on the so-called Target Normal Sheath Acceleration (TNSA) mechanisms: a high power laser is focused onto a solid target (thin metallic or plastic foil) and interact with matter at very high intensity, thus generating a plasma; as a consequence "hot" electrons are produced and move into the forward direction through the target. Protons are generated at the target rear side, electrons try to escape from the target and an ultra-strong quasi-electrostatic field (~1TV/m) is generated. Such a field can accelerate protons with a wide energy spectrum (1-200 MeV) in a few tens of micrometers. The proton beam characteristics depend on the laser parameters and on the target geometry and nature. This technique has been validated experimentally in several high power laser facilities by accelerating protons coming from hydrogenated contaminant (mainly water) at the rear of metallic target, however, several research groups are investigating the possibility to perform experiments by using "pure" hydrogen targets. In this context, the low temperature laboratory at CEA-Grenoble has developed a cryostat able to continuously produce a thin hydrogen ribbon (from 40 to 100 microns thick). A new extrusion concept, without any moving part has been carried out, using only the thermodynamic properties of the fluid. First results and perspectives are presented in this paper.

Optically pumped laser systems

International Nuclear Information System (INIS)

DeMaria, A.J.; Mack, M.E.

1975-01-01

Laser systems which are pumped by an electric discharge formed in a gas are disclosed. The discharge is in the form of a vortex stabilized electric arc which is triggered with an auxiliary energy source. At high enough repetition rates residual ionization between successive pulses contributes to the pulse stabilization. The arc and the gain medium are positioned inside an optical pumping cavity where light from the arc is coupled directly into the gain medium

Applications of optical sensing for laser cutting and drilling.

Science.gov (United States)

Fox, Mahlen D T; French, Paul; Peters, Chris; Hand, Duncan P; Jones, Julian D C

2002-08-20

Any reliable automated production system must include process control and monitoring techniques. Two laser processing techniques potentially lending themselves to automation are percussion drilling and cutting. For drilling we investigate the performance of a modification of a nonintrusive optical focus control system we previously developed for laser welding, which exploits the chromatic aberrations of the processing optics to determine focal error. We further developed this focus control system for closed-loop control of laser cutting. We show that an extension of the technique can detect deterioration in cut quality, and we describe practical trials carried out on different materials using both oxygen and nitrogen assist gas. We base our techniques on monitoring the light generated by the process, captured nonintrusively by the effector optics and processed remotely from the workpiece. We describe the relationship between the temporal and the chromatic modulation of the detected light and process quality and show how the information can be used as the basis of a process control system.

Modelling exciton–phonon interactions in optically driven quantum dots

DEFF Research Database (Denmark)

Nazir, Ahsan; McCutcheon, Dara

2016-01-01

We provide a self-contained review of master equation approaches to modelling phonon effects in optically driven self-assembled quantum dots. Coupling of the (quasi) two-level excitonic system to phonons leads to dissipation and dephasing, the rates of which depend on the excitation conditions...

Instabilities of line-driven stellar winds. V. Effect of an optically thick continuum

International Nuclear Information System (INIS)

Owocki, S.P.; Rybicki, G.B.

1991-01-01

Earlier analyses of the linear instability of line-driven stellar winds are extended to the case, relevant to Wolf-Rayet stars, in which the continuum remains optically thick well above the sonic point. It is found that an optically thick flow driven by pure scattering lines is stabilized by the drag effect of the diffuse, scattered radiation. However, even a relatively small photon destruction probability can cause a flow with continuum optical thickness much greater than 1 to remain unstable, with a given growth rate. The implications of these results for the variability characteristics of winds from Wolf-Rayet stars are briefly discussed. 16 refs

Advances in lasers and optical micro-nano-systems

Science.gov (United States)

Laurell, F.; Fazio, E.

2010-09-01

Lasers represent a well consolidated technology: nevertheless, research in this field remains very active and productive, in both basic and applied directions. At the moment significant attention is given to those sources that bring together high power and compactness. Such high power lasers find important applications for material treatments and such applications are presented by Ehsani et al and Saiedeh Saghafi et al, in the treatment of dielectric thin films (Alteration of optical and morphological properties of polycarbonate illuminated by visible/IR laser beams) or of biological tissues like pistachio seeds (Investigating the effects of laser beams (532 and 660 nm) in annihilation of pistachio mould fungus using spectrophotometry analysis). In particular the latter paper show how laser sources can find very important applications in new domains, preserving goods and food without the need for preservatives or pesticides by simply sterilizing them using light. Optical Micro and Nano Systems presents a new domain for exploration. In this framework this special issue is very attractive, because it assembles papers reporting new results in three directions: new techniques for monitoring integrated micro- and nano-systems, new integrated systems and novel high performance metamaterial configurations. Integrated micro-components can be monitored and controlled using reflectance measurements as presented by Piombini et al (Toward the reflectance measurement of micro components). Speckle formation during laser beam reflection can also be a very sophisticated tool for detecting ultra-precise displacements, as presented by Filter et al (High resolution displacement detection with speckles : accuracy limits in linear displacement speckle metrology). Three dimensional integrated optical structures is indeed a big challenge and a peculiarity of photonics, they can be formed through traditional holography or using more sophisticated and novel ! technologies. Thus, special

Very high repetition-rate electro-optical cavity-dumped Nd: YVO4 laser with optics and dynamics stabilities

Science.gov (United States)

Liu, Xuesong; Shi, Zhaohui; Huang, Yutao; Fan, Zhongwei; Yu, Jin; Zhang, Jing; Hou, Liqun

2015-02-01

In this paper, a very high repetition-rate, short-pulse, electro-optical cavity-dumped Nd: YVO4 laser is experimentally and theoretically investigated. The laser performance is optimized from two aspects. Firstly, the laser resonator is designed for a good thermal stability under large pump power fluctuation through optics methods. Secondly, dynamics simulation as well as experiments verifies that cavity dumping at very high repetition rate has better stability than medium/high repetition rate. At 30 W, 880 nm pump power, up to 500 kHz, constant 5 ns, stable 1064 nm fundamental-mode laser pulses can be obtained with 10 W average output power.

Reduction of damage initiation density in fused silica optics via UV laser conditioning

Science.gov (United States)

Peterson, John E.; Maricle, Stephen M.; Brusasco, Raymond M.; Penetrante, Bernardino M.

2004-03-16

The present invention provides a method for reducing the density of sites on the surface of fused silica optics that are prone to the initiation of laser-induced damage, resulting in optics which have far fewer catastrophic defects and are better capable of resisting optical deterioration upon exposure for a long period of time to a high-power laser beam having a wavelength of about 360 nm or less. The initiation of laser-induced damage is reduced by conditioning the optic at low fluences below levels that normally lead to catastrophic growth of damage. When the optic is then irradiated at its high fluence design limit, the concentration of catastrophic damage sites that form on the surface of the optic is greatly reduced.

QUANTITATIVE DETECTION OF ENVIRONMENTALLY IMPORTANT DYES USING DIODE LASER/FIBER-OPTIC RAMAN

Science.gov (United States)

A compact diode laser/fiber-optic Raman spectrometer is used for quantitative detection of environmentally important dyes. This system is based on diode laser excitation at 782 mm, fiber optic probe technology, an imaging spectrometer, and state-of-the-art scientific CCD camera. ...

The Laser Guide Star System for Adaptive Optics at Subaru Telescope

Science.gov (United States)

Hayano, Y.; Saito, Y.; Ito, M.; Saito, N.; Akagawa, K.; Takazawa, A.; Ito, M.; Wada, S.; Takami, H.; Iye, M.

We report on the current status of developing the new laser guide star (LGS) system for the Subaru adaptive optics (AO) system. We have three major subsystems: the laser unit, the relay optical fiber and the laser launching telescope. A 4W-class all-solid-state 589nm laser has been developed as a light source for sodium laser guide star. We use two mode-locked Nd:YAG lasers operated at the wavelength of 1064nm and 1319nm to generate sum-frequency conversion into 589nm. The side-LD pumped configuration is used for the mode-locked Nd:YAG lasers. We have carefully considered the thermal lens effect in the cavity to achieve a high beam quality with TEM00; M2 = 1.06. The mode-locked frequency is selected at 143 MHz. We obtained the output powers of 16.5 W and 5.0 W at 1064nm and 1319 nm. Sum frequency generated by mixing two synchronized Nd:YAG mode-locked pulsed beams is precisely tuned to the sodium D2 line by thermal control of the etalon in the 1064nm Nd:YAG laser by observing the maximum fluorescence intensity of heated sodium vapor cell. The maximum output power at 589.159 nm reaches to 4.6 W using a PPMgOSLT crystal as a nonlinear optical crystal. And the output power can be maintained within a stability of +/- 1.2% for more than 3 days without optical damage. We developed a single-mode photonic crystal fiber (PCF) to relay the laser beam from laser clean room, in which the laser unit is located on the Nasmyth platform, to the laser launching telescope mounted behind the secondary mirror of Subaru Telescope. The photonic crystal fiber has solid pure silica core with the mode field diameter of 14 micron, which is relatively larger than that of the conventional step-index type single mode fiber. The length of the PCF is 35m and transmission loss due to the pure silica is 10dB/km at 589nm, which means PCF transmits 92% of the laser beam. We have preliminary achieved 75% throughput in total. Small mode-locked pulse width in time allows us to transmit the high

Neutron Generation by Laser-Driven Spherically Convergent Plasma Fusion

Science.gov (United States)

Ren, G.; Yan, J.; Liu, J.; Lan, K.; Chen, Y. H.; Huo, W. Y.; Fan, Z.; Zhang, X.; Zheng, J.; Chen, Z.; Jiang, W.; Chen, L.; Tang, Q.; Yuan, Z.; Wang, F.; Jiang, S.; Ding, Y.; Zhang, W.; He, X. T.

2017-04-01

We investigate a new laser-driven spherically convergent plasma fusion scheme (SCPF) that can produce thermonuclear neutrons stably and efficiently. In the SCPF scheme, laser beams of nanosecond pulse duration and 1 014- 1 015 W /cm2 intensity uniformly irradiate the fuel layer lined inside a spherical hohlraum. The fuel layer is ablated and heated to expand inwards. Eventually, the hot fuel plasmas converge, collide, merge, and stagnate at the central region, converting most of their kinetic energy to internal energy, forming a thermonuclear fusion fireball. With the assumptions of steady ablation and adiabatic expansion, we theoretically predict the neutron yield Yn to be related to the laser energy EL, the hohlraum radius Rh, and the pulse duration τ through a scaling law of Yn∝(EL/Rh1.2τ0.2 )2.5. We have done experiments at the ShengGuangIII-prototype facility to demonstrate the principle of the SCPF scheme. Some important implications are discussed.

Push-Pull Laser-Atomic Oscillator

International Nuclear Information System (INIS)

Jau, Y.-Y.; Happer, W.

2007-01-01

A vapor of alkali-metal atoms in the external cavity of a semiconductor laser, pumped with a time-independent injection current, can cause the laser to self-modulate at the 'field-independent 0-0 frequency' of the atoms. Push-pull optical pumping by the modulated light drives most of the atoms into a coherent superposition of the two atomic sublevels with an azimuthal quantum number m=0. The atoms modulate the optical loss of the cavity at the sharply defined 0-0 hyperfine frequency. As in a maser, the system is not driven by an external source of microwaves, but a very stable microwave signal can be recovered from the modulated light or from the modulated voltage drop across the laser diode. Potential applications for this new phenomenon include atomic clocks, the production of long-lived coherent atomic states, and the generation of coherent optical combs

High energy laser optics manufacturing: a preliminary study

International Nuclear Information System (INIS)

Baird, E.D.

1980-07-01

This report presents concepts and methods, major conclusions, and major recommendations concerning the fabrication of high energy laser optics (HELO) that are to be machined by the Large Optics Diamond Turning Machine (LODTM) at the Lawrence Livermore National Laboratory (LLNL). Detailed discussions of concepts and methods proposed for metrological operations, polishing of reflective surfaces, mounting of optical components, construction of mirror substrates, and applications of coatings are included

Low-power laser therapy for carpal tunnel syndrome: effective optical power

Directory of Open Access Journals (Sweden)

Yan Chen

2016-01-01

Full Text Available Low-power laser therapy has been used for the non-surgical treatment of mild to moderate carpal tunnel syndrome, although its efficacy has been a long-standing controversy. The laser parameters in low-power laser therapy are closely related to the laser effect on human tissue. To evaluate the efficacy of low-power laser therapy, laser parameters should be accurately measured and controlled, which has been ignored in previous clinical trials. Here, we report the measurement of the effective optical power of low-power laser therapy for carpal tunnel syndrome. By monitoring the backside reflection and scattering laser power from human skin at the wrist, the effective laser power can be inferred. Using clinical measurements from 30 cases, we found that the effective laser power differed significantly among cases, with the measured laser reflection coefficient ranging from 1.8% to 54%. The reflection coefficient for 36.7% of these 30 cases was in the range of 10–20%, but for 16.7% of cases, it was higher than 40%. Consequently, monitoring the effective optical power during laser irradiation is necessary for the laser therapy of carpal tunnel syndrome.

Communication with diode laser: short distance line of sight communication using fiber optics

International Nuclear Information System (INIS)

Mirza, A.H.

1999-01-01

The objective of this project is to carry audio signal from transmitting station to a short distance receiving station along line of sight and also communication through fiber optics is performed, using diode laser light as carrier. In this project optical communication system, modulation techniques, basics of laser and causes of using diode laser are discussed briefly. Transmitter circuit and receiver circuit are fully described. Communication was performed using pulse width modulation technique. Optical fiber communication have many advantages over other type of conventional communication techniques. This report contains the description of optical fiber communication and compared with other communication systems. (author)

Studies of bandwidth dependence of laser plasma instabilities driven by the Nike laser

Science.gov (United States)

Weaver, J.; Kehne, D.; Obenschain, S.; Serlin, V.; Schmitt, A. J.; Oh, J.; Lehmberg, R. H.; Brown, C. M.; Seely, J.; Feldman, U.

2012-10-01

Experiments at the Nike laser facility of the Naval Research Laboratory are exploring the influence of laser bandwidth on laser plasma instabilities (LPI) driven by a deep ultraviolet pump (248 nm) that incorporates beam smoothing by induced spatial incoherence (ISI). In early ISI studies with longer wavelength Nd:glass lasers (1054 nm and 527 nm),footnotetextObenschain, PRL 62(1989);Mostovych, PRL 62(1987);Peyser, Phys. Fluids B 3(1991). stimulated Raman scattering, stimulated Brillouin scattering, and the two plasmon decay instability were reduced when wide bandwidth ISI (δν/ν˜0.03-0.19%) pulses irradiated targets at moderate to high intensities (10^14-10^15 W/cm^2). The current studies will compare the emission signatures of LPI from planar CH targets during Nike operation at large bandwidth (δν˜1THz) to observations for narrower bandwidth operation (δν˜0.1-0.3THz). These studies will help clarify the relative importance of the short wavelength and wide bandwidth to the increased LPI intensity thresholds observed at Nike. New pulse shapes are being used to generate plasmas with larger electron density scale-lengths that are closer to conditions during pellet implosions for direct drive inertial confinement fusion.

Near and long term pulse power requirements for laser driven inertial confinement fusion

International Nuclear Information System (INIS)

Gagnon, W.L.

1979-01-01

At the Lawrence Livermore Laboraory, major emphasis has been placed upon the development of large, ND:glass laser systems in order to address the basic physics issues associated with light driven fusion targets. A parallel program is directed toward the development of lasers which exhibit higher efficiencies and shorter wavelengths and are thus more suitable as drivers for fusion power plants. This paper discusses the pulse power technology which has been developed to meet the near and far term needs of the laser fusion program at Livermore

High-brightness switchable multiwavelength remote laser in air

Energy Technology Data Exchange (ETDEWEB)

Yao Jinping; Cheng Ya; Xu Zhizhan [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Zeng Bin; Li Guihua; Chu Wei; Ni Jielei; Zhang Haisu [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Graduate School of Chinese Academy of Sciences, Beijing 100080 (China); Xu Huailiang [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012 (China); Chin, See Leang [Center for Optics, Universite Laval, Quebec City, Quebec G1V 0A6 (Canada)

2011-11-15

We demonstrate a harmonic-seeded switchable multiwavelength laser in air driven by intense midinfrared femtosecond laser pulses, in which population inversion occurs at an ultrafast time scale (i.e., less than {approx}200 fs) owing to direct formation of excited molecular nitrogen ions by strong-field ionization of inner-valence electrons. The bright multiwavelength laser in air opens the perspective for remote detection of multiple pollutants based on nonlinear optical spectroscopy.

Strong optical feedback in birefringent dual frequency laser

Institute of Scientific and Technical Information of China (English)

Mao Wei; Zhang Shu-Lian

2006-01-01

Strong optical feedback in a birefringent dual frequency He-Ne laser with a high reflectivity feedback mirror has been investigated for the first time. The output characteristics of two orthogonally polarized modes are demonstrated in two different optical feedback cases: one is for both modes being fed back and the other is for only one of the modes being fed back. Strong mode competition can be observed between the two modes with strong optical feedback. And when one mode's intensity is near its maximum, the other mode is nearly extinguished. When both modes are fed back into the laser cavity, the mode competition is stronger than when only one mode is fed back. The difference in initial intensity between the two orthogonally polarized modes plays an important role in the mode competition, which has been experimentally and theoretically demonstrated.

Combined advanced finishing and UV laser conditioning process for producing damage resistant optics

Science.gov (United States)

Menapace, Joseph A.; Peterson, John E.; Penetrante, Bernardino M.; Miller, Philip E.; Parham, Thomas G.; Nichols, Michael A.

2005-07-26

A method for reducing the density of sites on the surface of fused silica optics that are prone to the initiation of laser-induced damage, resulting in optics which have far fewer catastrophic defects, and are better capable of resisting optical deterioration upon exposure to a high-power laser beam.

Theoretical model for a background noise limited laser-excited optical filter for doubled Nd lasers

Science.gov (United States)

Shay, Thomas M.; Garcia, Daniel F.

1990-01-01

A simple theoretical model for the calculation of the dependence of filter quantum efficiency versus laser pump power in an atomic Rb vapor laser-excited optical filter is reported. Calculations for Rb filter transitions that can be used to detect the practical and important frequency-doubled Nd lasers are presented. The results of these calculations show the filter's quantum efficiency versus the laser pump power. The required laser pump powers required range from 2.4 to 60 mW/sq cm of filter aperture.

Development of high-power optically-pumped far-infrared lasers for plasma diagnostics

International Nuclear Information System (INIS)

Yamanaka, Masanobu; Yamanaka, Tatsuhiko; Mitsuishi, Akiyoshi; Fujita, Shigeru; Tsunawaki, Yoshiaki.

1982-01-01

The activities for developing an over 0.1-MW optically-pumped 385-μm D 2 O laser and a CW optically-pumped 382.9-μm CH 2 F 2 laser as local oscillator for measurement of ion temperature in Tokamaks are described. (author)

Role of resistivity gradient in laser-driven ion acceleration

Directory of Open Access Journals (Sweden)

L. A. Gizzi

2011-01-01

Full Text Available It was predicted that, when a fast electron beam with some angular spread is normally incident on a resistivity gradient, magnetic field generation can occur that can inhibit beam propagation [A. R. Bell et al., Phys. Rev. E 58, 2471 (1998PLEEE81063-651X10.1103/PhysRevE.58.2471]. This effect can have consequences on the laser-driven ion acceleration. In the experiment reported here, we compare ion emission from laser irradiated coated and uncoated metal foils and we show that the ion beam from the coated target has a much smaller angular spread. Detailed hybrid numerical simulations confirm that the inhibition of fast electron transport through the resistivity gradient may explain the observed effect.

An online, energy-resolving beam profile detector for laser-driven proton beams

Energy Technology Data Exchange (ETDEWEB)

Metzkes, J.; Rehwald, M.; Obst, L.; Schramm, U. [Helmholtz-Zentrum Dresden–Rossendorf (HZDR), Bautzner Landstr. 400, 01328 Dresden (Germany); Technische Universität Dresden, 01062 Dresden (Germany); Zeil, K.; Kraft, S. D.; Sobiella, M.; Schlenvoigt, H.-P. [Helmholtz-Zentrum Dresden–Rossendorf (HZDR), Bautzner Landstr. 400, 01328 Dresden (Germany); Karsch, L. [OncoRay-National Center for Radiation Research in Oncology, Technische Universität Dresden, 01307 Dresden (Germany)

2016-08-15

In this paper, a scintillator-based online beam profile detector for the characterization of laser-driven proton beams is presented. Using a pixelated matrix with varying absorber thicknesses, the proton beam is spatially resolved in two dimensions and simultaneously energy-resolved. A thin plastic scintillator placed behind the absorber and read out by a CCD camera is used as the active detector material. The spatial detector resolution reaches down to ∼4 mm and the detector can resolve proton beam profiles for up to 9 proton threshold energies. With these detector design parameters, the spatial characteristics of the proton distribution and its cut-off energy can be analyzed online and on-shot under vacuum conditions. The paper discusses the detector design, its characterization and calibration at a conventional proton source, as well as the first detector application at a laser-driven proton source.

Optical wave microphone measurements of laser ablation of copper in supercritical carbon dioxide

Energy Technology Data Exchange (ETDEWEB)

Mitsugi, Fumiaki, E-mail: mitsugi@cs.kumamoto-u.ac.jp [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Ikegami, Tomoaki [Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Kumamoto 860-8555 (Japan); Nakamiya, Toshiyuki; Sonoda, Yoshito [Graduate School of Industrial Engineering, Tokai University, 9-1-1 Toroku, Kumamoto 862-8652 (Japan)

2013-11-29

Laser ablation plasma in a supercritical fluid has attracted much attention recently due to its usefulness in forming nanoparticles. Observation of the dynamic behavior of the supercritical fluid after laser irradiation of a solid is necessary for real-time monitoring and control of laser ablation. In this study, we utilized an optical wave microphone to monitor pulsed laser irradiation of a solid in a supercritical fluid. The optical wave microphone works based on Fraunhofer diffraction of phase modulation of light by changes in refractive index. We hereby report on our measurements for pulsed laser irradiation of a Cu target in supercritical carbon dioxide using an optical wave microphone. Photothermal acoustic waves which generated after single pulsed laser irradiation of a Cu target were detectable in supercritical carbon dioxide. The speed of sound around the critical point of supercritical carbon dioxide was clearly slower than that in gas. The optical wave microphone detected a signal during laser ablation of Cu in supercritical carbon dioxide that was caused by shockwave degeneration. - Highlights: • Photothermal acoustic wave in supercritical fluid was observed. • Sound speed around the critical point was slower than that in gas. • Optical wave microphone detected degeneration of a shockwave. • Ablation threshold of a solid in supercritical fluid can be estimated. • Generation of the second shockwave in supercritical phase was suggested.

Development of surgical CW Nd:YAG laser with optical fiber delivery system

International Nuclear Information System (INIS)

Kim, Cheol Jung; Kim, Jeong Mook; Jung, Chin Mann; Kim, Kwang Suk; Kim, Min Suk; Cho, Jae Wan; Kim, Duk Hyun

1992-06-01

We developed a surgical CW Nd:YAG laser with optical fiber delivery system. Several commercial models have been investigated in design and performance. We improved its quality to the level of commercial Nd:YAG laser by an endurance test for each parts of laser system. The maximum power of our surgical laser was 150 W and the laser pulse width could be controlled to 99 sec continuously by 0.1 sec. Many optical parts were localized and lowered much in cost. Only few parts were imported and almost 90% in cost were localized. Also, to find out the maintenance problem of this surgical laser, it was applicated to the production line of our joint company. (Author)

CO2 laser-driven Stirling engine. [space power applications

Science.gov (United States)

Lee, G.; Perry, R. L.; Carney, B.

1978-01-01

A 100-W Beale free-piston Stirling engine was powered remotely by a CO2 laser for long periods of time. The engine ran on both continuous-wave and pulse laser input. The working fluid was helium doped with small quantities of sulfur hexafluoride, SF6. The CO2 radiation was absorbed by the vibrational modes of the sulfur hexafluoride, which in turn transferred the energy to the helium to drive the engine. Electrical energy was obtained from a linear alternator attached to the piston of the engine. Engine pressures, volumes, and temperatures were measured to determine engine performance. It was found that the pulse radiation mode was more efficient than the continuous-wave mode. An analysis of the engine heat consumption indicated that heat losses around the cylinder and the window used to transmit the beam into the engine accounted for nearly half the energy input. The overall efficiency, that is, electrical output to laser input, was approximately 0.75%. However, this experiment was not designed for high efficiency but only to demonstrate the concept of a laser-driven engine. Based on this experiment, the engine could be modified to achieve efficiencies of perhaps 25-30%.

Electro-optic analysis of the influence of target geometry on electromagnetic pulses generated by petawatt laser-matter interactions

Science.gov (United States)

Robinson, Timothy; Giltrap, Samuel; Eardley, Samuel; Consoli, Fabrizio; De Angelis, Riccardo; Ingenito, Francesco; Stuart, Nicholas; Verona, Claudio; Smith, Roland A.

2018-01-01

We present an analysis of strong laser-driven electromagnetic pulses using novel electro-optic diagnostic techniques. A range of targets were considered, including thin plastic foils (20-550 nm) and mass-limited, optically-levitated micro-targets. Results from foils indicate a dependence of EMP on target thickness, with larger peak electric fields observed with thinner targets. Spectral analysis suggests high repeatability between shots, with identified spectral features consistently detected with earth following ejection of hot electrons from the plasma, in contrast to predictions for pin-mounted foils in the Poyé EMP generation model. With levitated targets, no EMP was measurable above the noise threshold of any diagnostic, despite observation of protons accelerated to >30 MeV energies, suggesting the discharge current contribution to EMP is dominant.

Semiconductor optical amplifier-based heterodyning detection for resolving optical terahertz beat-tone signals from passively mode-locked semiconductor lasers

International Nuclear Information System (INIS)

Latkowski, Sylwester; Maldonado-Basilio, Ramon; Carney, Kevin; Parra-Cetina, Josue; Philippe, Severine; Landais, Pascal

2010-01-01

An all-optical heterodyne approach based on a room-temperature controlled semiconductor optical amplifier (SOA) for measuring the frequency and linewidth of the terahertz beat-tone signal from a passively mode-locked laser is proposed. Under the injection of two external cavity lasers, the SOA acts as a local oscillator at their detuning frequency and also as an optical frequency mixer whose inputs are the self-modulated spectrum of the device under test and the two laser beams. Frequency and linewidth of the intermediate frequency signal (and therefore, the beat-tone signal) are resolved by using a photodiode and an electrical spectrum analyzer.

Fiber optic coherent laser radar 3d vision system

International Nuclear Information System (INIS)

Sebastian, R.L.; Clark, R.B.; Simonson, D.L.

1994-01-01

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 of 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

Lasers and optical fibers in medicine

CERN Document Server

Katzir, Abraham

1993-01-01

The increasing use of fiber optics in the field of medicine has created a need for an interdisciplinary perspective of the technology and methods for physicians as well as engineers and biophysicists. This book presents a comprehensive examination of lasers and optical fibers in an hierarchical, three-tier system. Each chapter is divided into three basic sections: the Fundamentals section provides an overview of basic concepts and background; the Principles section offers an in-depth engineering approach; and the Advances section features specific information on systems an

Optical gain in an optically driven three-level ? system in atomic Rb vapor

Science.gov (United States)

Ballmann, C. W.; Yakovlev, V. V.

2018-06-01

In this work, we report experimentally achieved optical gain of a weak probe beam in a three-level ? system in a low density Rubidium vapor cell driven by a single pump beam. The maximum measured gain of the probe beam was about 0.12%. This work could lead to new approaches for enhancing molecular spectroscopy applications.

Laser driven compression and neutron generation with spherical shell targets

International Nuclear Information System (INIS)

Campbell, P.M.; Hammerling, P.; Johnson, R.R.; Kubis, J.J.; Mayer, F.J.

1977-01-01

Laser-driven implosion experiments using DT-gas-filled spherical glass-shell targets are described. Neutron yields to 5 x 10 7 are produced from implosions of small ( -- 55 μm-diameter) targets spherically illuminated with an on-target laser power of 0.4 terawatt. Nuclear reaction product diagnostics, X-ray pinhole photographs, fast-ion spectra and X-ray measurements are used in conjunction with hydrodynamic computer code simulations to investigate the implosion phenomenology as well as the target corona evolution. Simulations using completely classical effects are not able to describe the full range of experimental data. Electron or radiation preheating may be required to explain some implosion measurements. (auth.)

Dynamic control of laser driven proton beams by exploiting self-generated, ultrashort electromagnetic pulses

Energy Technology Data Exchange (ETDEWEB)

Kar, S., E-mail: s.kar@qub.ac.uk; Ahmed, H.; Nersisyan, G.; Hanton, F.; Naughton, K.; Lewis, C. L. S.; Borghesi, M. [Centre for Plasma Physics, School of Mathematics and Physics, Queen' s University Belfast, Belfast BT7 1NN (United Kingdom); Brauckmann, S.; Giesecke, A. L.; Willi, O. [Institut für Laser-und Plasmaphysik, Heinrich-Heine-Universität, Düsseldorf (Germany)

2016-05-15

As part of the ultrafast charge dynamics initiated by high intensity laser irradiations of solid targets, high amplitude EM pulses propagate away from the interaction point and are transported along any stalks and wires attached to the target. The propagation of these high amplitude pulses along a thin wire connected to a laser irradiated target was diagnosed via the proton radiography technique, measuring a pulse duration of ∼20 ps and a pulse velocity close to the speed of light. The strong electric field associated with the EM pulse can be exploited for controlling dynamically the proton beams produced from a laser-driven source. Chromatic divergence control of broadband laser driven protons (upto 75% reduction in divergence of >5 MeV protons) was obtained by winding the supporting wire around the proton beam axis to create a helical coil structure. In addition to providing focussing and energy selection, the technique has the potential to post-accelerate the transiting protons by the longitudinal component of the curved electric field lines produced by the helical coil lens.

Laser backlight unit based on a leaky optical fiber

Science.gov (United States)

Okuda, Yuuto; Onoda, Kousuke; Fujieda, Ichiro

2012-07-01

A backlight unit is constructed by laying out an optical fiber on a two-dimensional plane and letting the light leak out in a controlled manner. In experiment, we formed multiple grooves on the surface of a plastic optical fiber by pressing a heated knife edge. The depth of the groove determined the percentage of the optical power leaking out. The optical fiber with multiple grooves was embedded in an acrylic plate with a spiral trench, and a diffuser sheet was placed over it. When we injected laser light into the end of the optical fiber, this configuration successfully worked as an area illuminator. However, the coherent nature of the laser light caused severe speckle noise. We evaluated the speckle contrast under darkness, and it varied from 80% to 23%, depending on the lens aperture used to capture the images of the illuminator. We glued an ultrasound generator to the optical fiber to introduce phase modulation for the light propagating inside the optical fiber. In this way, the speckle contrast was reduced by a factor of seven to four. Under room lighting, the speckle noise was made barely noticeable by turning on the ultrasound generator.

Nonlinear optics and solid-state lasers advanced concepts, tuning-fundamentals and applications

CERN Document Server

Yao, Jianquan

2012-01-01

This book covers the complete spectrum of nonlinear optics and all solid state lasers.The book integrates theory, calculations and practical design, technology, experimental schemes and applications. With the expansion and further development of Laser technology, the wavelength spectrum of Lasers had to be enlarged, even to be tunable which requires the use of nonlinear optical and Laser tunable technology. It systematically summarizes and integrates the analysis of international achievements within the last 20 years in this field. It will be helpful for university teachers, graduate students as well as engineers.

Chaos-pass filtering in injection-locked semiconductor lasers

International Nuclear Information System (INIS)

Murakami, Atsushi; Shore, K. Alan

2005-01-01

Chaos-pass filtering (CPF) of semiconductor lasers has been studied theoretically. CPF is a phenomenon which occurs in laser chaos synchronization by injection locking and is a fundamental technique for the extraction of messages at the receiver laser in chaotic communications systems. We employ a simple theory based on driven damped oscillators to clarify the physical background of CPF. The receiver laser is optically driven by injection from the transmitter laser. We have numerically investigated the response characteristics of the receiver when it is driven by periodic (message) and chaotic (carrier) signals. It is thereby revealed that the response of the receiver laser in the two cases is quite different. For the periodic drive, the receiver exhibits a response depending on the signal frequency, while the chaotic drive provides a frequency-independent synchronous response to the receiver laser. We verify that the periodic and chaotic drives occur independently in the CPF response, and, consequently, CPF can be clearly understood in the difference of the two drives. Message extraction using CPF is also examined, and the validity of our theoretical explanation for the physical mechanism underlying CPF is thus verified

The impact of laser ablation on optical soft tissue differentiation for tissue specific laser surgery-an experimental ex vivo study

Directory of Open Access Journals (Sweden)

Stelzle Florian

2012-06-01

Full Text Available Abstract Background Optical diffuse reflectance can remotely differentiate various bio tissues. To implement this technique in an optical feedback system to guide laser surgery in a tissue-specific way, the alteration of optical tissue properties by laser ablation has to be taken into account. It was the aim of this study to evaluate the general feasibility of optical soft tissue differentiation by diffuse reflectance spectroscopy under the influence of laser ablation, comparing the tissue differentiation results before and after laser intervention. Methods A total of 70 ex vivo tissue samples (5 tissue types were taken from 14 bisected pig heads. Diffuse reflectance spectra were recorded before and after Er:YAG-laser ablation. The spectra were analyzed and differentiated using principal component analysis (PCA, followed by linear discriminant analysis (LDA. To assess the potential of tissue differentiation, area under the curve (AUC, sensitivity and specificity was computed for each pair of tissue types before and after laser ablation, and compared to each other. Results Optical tissue differentiation showed good results before laser exposure (total classification error 13.51%. However, the tissue pair nerve and fat yielded lower AUC results of only 0.75. After laser ablation slightly reduced differentiation results were found with a total classification error of 16.83%. The tissue pair nerve and fat showed enhanced differentiation (AUC: 0.85. Laser ablation reduced the sensitivity in 50% and specificity in 80% of the cases of tissue pair comparison. The sensitivity of nerve–fat differentiation was enhanced by 35%. Conclusions The observed results show the general feasibility of tissue differentiation by diffuse reflectance spectroscopy even under conditions of tissue alteration by laser ablation. The contrast enhancement for the differentiation between nerve and fat tissue after ablation is assumed to be due to laser removal of the

Acceleration of laser-injected electron beams in an electron-beam driven plasma wakefield accelerator

International Nuclear Information System (INIS)

Knetsch, Alexander

2018-03-01

Plasma wakefields deliver accelerating fields that are approximately a 100 times higher than those in conventional radiofrequency or even superconducting radiofrequency cavities. This opens a transformative path towards novel, compact and potentially ubiquitous accelerators. These prospects, and the increasing demand for electron accelerator beamtime for various applications in natural, material and life sciences, motivate the research and development on novel plasma-based accelerator concepts. However, these electron beam sources need to be understood and controlled. The focus of this thesis is on electron beam-driven plasma wakefield acceleration (PWFA) and the controlled injection and acceleration of secondary electron bunches in the accelerating wake fields by means of a short-pulse near-infrared laser. Two laser-triggered injection methods are explored. The first one is the Trojan Horse Injection, which relies on very good alignment and timing control between electron beam and laser pulse and then promises electron bunches with hitherto unprecedented quality as regards emittance and brightness. The physics of electron injection in the Trojan Horse case is explored with a focus on the final longitudinal bunch length. Then a theoretical and numerical study is presented that examines the physics of Trojan Horse injection when performed in an expanding wake generated by a smooth density down-ramp. The benefits are radically decreased drive-electron bunch requirements and a unique bunch-length control that enables longitudinal electron-bunch shaping. The second laser-triggered injection method is the Plasma Torch Injection, which is a versatile, all-optical laser-plasma-based method capable to realize tunable density downramp injection. At the SLAC National Laboratory, the first proof-of-principle was achieved both for Trojan Horse and Plasma Torch injection. Setup details and results are reported in the experimental part of the thesis along with the commissioning

Tunable and broadband microwave frequency combs based on a semiconductor laser with incoherent optical feedback

International Nuclear Information System (INIS)

Zhao Mao-Rong; Wu Zheng-Mao; Deng Tao; Zhou Zhen-Li; Xia Guang-Qiong

2015-01-01

Based on a semiconductor laser (SL) with incoherent optical feedback, a novel all-optical scheme for generating tunable and broadband microwave frequency combs (MFCs) is proposed and investigated numerically. The results show that, under suitable operation parameters, the SL with incoherent optical feedback can be driven to operate at a regular pulsing state, and the generated MFCs have bandwidths broader than 40 GHz within a 10 dB amplitude variation. For a fixed bias current, the line spacing (or repetition frequency) of the MFCs can be easily tuned by varying the feedback delay time and the feedback strength, and the tuning range of the line spacing increases with the increase in the bias current. The linewidth of the MFCs is sensitive to the variation of the feedback delay time and the feedback strength, and a linewidth of tens of KHz can be achieved through finely adjusting the feedback delay time and the feedback strength. In addition, mappings of amplitude variation, repetition frequency, and linewidth of MFCs in the parameter space of the feedback delay time and the feedback strength are presented. (paper)

Influence of optical feedback on laser frequency spectrum and threshold conditions

DEFF Research Database (Denmark)

Osmundsen, Jens Henrik; Gade, Niels

1983-01-01

The steady state behavior of the external cavity operated laser has been analyzed, taking into account multiple reflections. The effect of optical feedback is included in the phase- and gain-conditions by a factor which is shown to have a simple geometrical representation. From this representation...... it is easily seen how the laser frequency spectrum and the threshold gain depend on external parameters such as distance to the reflection point and the amount of optical feedback. Furthermore, by inserting a variable attenuator in the external cavity and measuring the threshold current versus transmittance we...... have simultaneously determined the photon lifetime and the absolute amount of optical feedback. For the laser considered we found the photon lifetimetau_{p} = 1.55ps....

Pulsed-diode-pumped, all-solid-state, electro-optically controlled picosecond Nd:YAG lasers

International Nuclear Information System (INIS)

Gorbunkov, Mikhail V; Shabalin, Yu V; Konyashkin, A V; Kostryukov, P V; Olenin, A N; Tunkin, V G; Morozov, V B; Rusov, V A; Telegin, L S; Yakovlev, D V

2005-01-01

The results of the development of repetitively pulsed, diode-pumped, electro-optically controlled picosecond Nd:YAG lasers of two designs are presented. The first design uses the active-passive mode locking with electro-optical lasing control and semiconductor saturable absorber mirrors (SESAM). This design allows the generation of 15-50-ps pulses with an energy up to 0.5 mJ and a maximum pulse repetition rate of 100 Hz. The laser of the second design generates 30-ps pulses due to combination of positive and negative electro-optical feedback and the control of the electro-optical modulator by the photocurrent of high-speed semiconductor structures. (active media. lasers)

Laser-driven ICF experiments: Laboratory Report No. 223

International Nuclear Information System (INIS)

McCrory, R.L.

1991-04-01

Laser irradiation uniformity is a key issue and is treated in some detail. The basic irradiation uniformity requirements and practical ways of achieving these requirements are both discussed, along with two beam-smoothing techniques: induced spatial incoherence (ISI), and smoothing by spectral dispersion (SSD). Experiments to measure and control the irradiation uniformity are also highlighted. Following the discussion of irradiation uniformity, a brief review of coronal physics is given, including the basic physical processes and their experimental signatures, together with a summary of pertinent diagnostics and results from experiments. Methods of determining ablation rates and thermal transport are also described. The hydrodynamics of laser-driven targets must be fully understood on the basis of experiments. Results from implosion experiments, including a brief description of the diagnostics, are presented. Future experiments aimed at determining ignition scaling and demonstrating hydrodynamically equivalent physics applicable to high-gain designs

Plasma mirrors for ultrahigh-intensity optics

Energy Technology Data Exchange (ETDEWEB)

Thaury, C; Quere, F; Levy, A; Ceccotti, T; Monot, P; Bougeard, M; Reau, F; D' Oliveira, P; Martin, PH [CEA, DSM, DRECAM, Serv Photons Atomes and Mol, F-91191 Gif Sur Yvette, (France); Geindre, J P; Audebert, P [Ecole Polytech, CNRS, Lab Utilisat Lasers Inst, F-91128 Palaiseau, (France); Marjoribanks, R [Univ Toronto, Dept Phys, Toronto, ON M5S 1A7, (Canada); Marjoribanks, R [Univ Toronto, Inst Opt Sci, Toronto, ON M5S 1A7, (Canada)

2007-07-01

Specular reflection is one of the most fundamental processes of optics. At moderate light intensities generated by conventional light sources this process is well understood. But at those capable of being produced by modern ultrahigh-intensity lasers, many new and potentially useful phenomena arise. When a pulse from such a laser hits an optically polished surface, it generates a dense plasma that itself acts as a mirror, known as a plasma mirror (PM). PMs do not just reflect the remainder of the incident beam, but can act as active optical elements. Using a set of three consecutive PMs in different regimes, we significantly improve the temporal contrast of femtosecond pulses, and demonstrate that high-order harmonics of the laser frequency can be generated through two distinct mechanisms. A better understanding of these processes should aid the development of laser-driven atto-second sources for use in fields from materials science to molecular biology. (authors)

Plasma mirrors for ultrahigh-intensity optics

International Nuclear Information System (INIS)

Thaury, C.; Quere, F.; Levy, A.; Ceccotti, T.; Monot, P.; Bougeard, M.; Reau, F.; D'Oliveira, P.; Martin, PH.; Geindre, J.P.; Audebert, P.; Marjoribanks, R.; Marjoribanks, R.

2007-01-01

Specular reflection is one of the most fundamental processes of optics. At moderate light intensities generated by conventional light sources this process is well understood. But at those capable of being produced by modern ultrahigh-intensity lasers, many new and potentially useful phenomena arise. When a pulse from such a laser hits an optically polished surface, it generates a dense plasma that itself acts as a mirror, known as a plasma mirror (PM). PMs do not just reflect the remainder of the incident beam, but can act as active optical elements. Using a set of three consecutive PMs in different regimes, we significantly improve the temporal contrast of femtosecond pulses, and demonstrate that high-order harmonics of the laser frequency can be generated through two distinct mechanisms. A better understanding of these processes should aid the development of laser-driven atto-second sources for use in fields from materials science to molecular biology. (authors)

Development of optical thin film technology for lasers and synchrotron radiation

International Nuclear Information System (INIS)

Apparao, K.V.S.R.; Bagchi, T.C.; Sahoo, N.K.

1985-01-01

Dielectric multilayer optical thin film devices play an important role not only in the working of lasers but also in different front line research activities using high power lasers and high intensity synchrotron radiation sources. Facilities are set up recently in the Spectroscopy Division to develop the optical thin film design and fabrication technologies indigeneously. Using the facilities thin film devices for different laser applications working in the wavelength range from 300 nm to 1064 nm were developed. Different technical aspects involved in the technology development are briefly described. (author)

Storage of laser pulses in a Fabry-Perot optical cavity for high flux x-ray

International Nuclear Information System (INIS)

Takezawa, K.; Honda, Y.; Sasao, N.; Araki, S.; Higashi, Y.; Taniguchi, T.; Urakawa, J.; Nomura, M.; Sakai, H.

2004-01-01

We have a plan to produce a high flux x-ray for medical use by using a Fabry-Perot optical cavity in which the lower pulses from a mode-locked laser are stored and enhanced. In this plan, the X-ray is produced from the Compton scattering of electrons in a storage ring with the laser light in the optical cavity. In order to increase X-ray flux, high power laser light is necessary. We show the enhancement of the laser power from the model locked laser with a Fabry-Perot optical cavity. (author)

Compact disposal of high-energy electron beams using passive or laser-driven plasma decelerating stage

Energy Technology Data Exchange (ETDEWEB)

Bonatto, A.; Schroeder, C. B.; Vay, J. -L.; Geddes, C. R.; Benedetti, C.; Esarey and, E.; Leemans, W. P.

2014-07-13

A plasma decelerating stage is investigated as a compact alternative for the disposal of high-energy beams (beam dumps). This could benefit the design of laser-driven plasma accelerator (LPA) applications that require transportability and or high-repetition-rate operation regimes. Passive and laser-driven (active) plasma-based beam dumps are studied analytically and with particle-in-cell (PIC) simulations in a 1D geometry. Analytical estimates for the beam energy loss are compared to and extended by the PIC simulations, showing that with the proposed schemes a beam can be efficiently decelerated in a centimeter-scale distance.

Laser-driven platform for generation and characterization of strong quasi-static magnetic fields

Czech Academy of Sciences Publication Activity Database

Santos, J.J.; Bailly-Grandvaux, M.; Giuffrida, Lorenzo; Forestier-Colleoni, P.; Fujioka, H.; Zhang, Z.; Korneev, P.; Bouillaud, R.; Dorard, S.; Batani, D.; Chevrot, M.; Cross, J. E.; Crowston, R.; Dubois, J.L.; Gazave, J.; Gregori, G.; d'Humieres, E.; Hulin, S.; Ishihara, K.; Kojima, S.; Loyez, E.; Marqués, J.-R.; Morace, A.; Nicolaï, P.; Peyrusse, O.; Poyé, A.; Raffestin, D.; Ribolzi, J.; Roth, M.; Schaumann, G.; Serres, F.; Tikhonchuk, V.T.; Vacar, P.; Woolsey, N.

2015-01-01

Roč. 17, Aug (2015), s. 1-10, č. článku 083051. ISSN 1367-2630 R&D Projects: GA MŠk ED1.1.00/02.0061 Grant - others:ELI Beamlines(XE) CZ.1.05/1.1.00/02.0061 Institutional support: RVO:68378271 Keywords : strong magnetic field * laser-driven coil targets * laser-plasma interaction Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.570, year: 2015

Coulomb-driven energy boost of heavy ions for laser-plasma acceleration.

Science.gov (United States)

Braenzel, J; Andreev, A A; Platonov, K; Klingsporn, M; Ehrentraut, L; Sandner, W; Schnürer, M

2015-03-27

An unprecedented increase of kinetic energy of laser accelerated heavy ions is demonstrated. Ultrathin gold foils have been irradiated by an ultrashort laser pulse at a peak intensity of 8×10^{19}  W/  cm^{2}. Highly charged gold ions with kinetic energies up to >200  MeV and a bandwidth limited energy distribution have been reached by using 1.3 J laser energy on target. 1D and 2D particle in cell simulations show how a spatial dependence on the ion's ionization leads to an enhancement of the accelerating electrical field. Our theoretical model considers a spatial distribution of the ionization inside the thin target, leading to a field enhancement for the heavy ions by Coulomb explosion. It is capable of explaining the energy boost of highly charged ions, enabling a higher efficiency for the laser-driven heavy ion acceleration.

Quantum confined laser devices optical gain and recombination in semiconductors

CERN Document Server

Blood, Peter

2015-01-01

The semiconductor laser, invented over 50 years ago, has had an enormous impact on the digital technologies that now dominate so many applications in business, commerce and the home. The laser is used in all types of optical fibre communication networks that enable the operation of the internet, e-mail, voice and skype transmission. Approximately one billion are produced each year for a market valued at around $5 billion. Nearly all semiconductor lasers now use extremely thin layers of light emitting materials (quantum well lasers). Increasingly smaller nanostructures are used in the form of quantum dots. The impact of the semiconductor laser is surprising in the light of the complexity of the physical processes that determine the operation of every device. This text takes the reader from the fundamental optical gain and carrier recombination processes in quantum wells and quantum dots, through descriptions of common device structures to an understanding of their operating characteristics. It has a consistent...

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-11-15

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

A microring multimode laser using hollow polymer optical fibre

Indian Academy of Sciences (India)

Dye-doped optical fibre; fibre laser; microcavity; whispering gallery mode. ... Cylindrical microcavities with diameters 155, 340 and 615 m were fabricated from a dye-doped hollow polymer optical fibre preform. ... International School of Photonics, Cochin University of Science and Technology, Kochi 682 022, India ...

Quantum Dot Laser for a Light Source of an Athermal Silicon Optical Interposer

Directory of Open Access Journals (Sweden)

Nobuaki Hatori

2015-04-01

Full Text Available This paper reports a hybrid integrated light source fabricated on a silicon platform using a 1.3 μm wavelength quantum dot array laser. Temperature insensitive characteristics up to 120 °C were achieved by the optimum quantum dot structure and laser structure. Light output power was obtained that was high enough to achieve an optical error-free link of a silicon optical interposer. Furthermore, we investigated a novel spot size convertor in a silicon waveguide suitable for a quantum dot laser for lower energy cost operation of the optical interposer.

Cleaning Process Versus Laser-Damage Threshold of Coated Optical Components

International Nuclear Information System (INIS)

Rigatti, A.L.

2005-01-01

The cleaning of optical surfaces is important in the manufacture of high-laser-damage-threshold coatings, which are a key component on peak-power laser systems such as OMEGA located at the Laboratory for Laser Energetics (LLE). Since cleaning adds time, labor, and ultimately cost to the final coated component, this experiment was designed to determine the impact of different cleaning protocols on the measured laser-damage performance

A study on the optical parts for a semiconductor laser module

Energy Technology Data Exchange (ETDEWEB)

Oh, Jun-Girl; Lee, Dong-Kil; Kim, Yang-Gyu; Lee, Kwang-Hoon; Park, Young-Sik [Korea Photonics Technology Institute, Gwangju (Korea, Republic of); Jang, Kwang-Ho [Hanvit Optoline, Gwangju (Korea, Republic of); Kang, Seung-Goo [COSET, Gwangju (Korea, Republic of)

2014-11-15

A semiconductor laser module consists of a LD (laser diode) chip that generates a laser beam, two cylindrical lenses to collimate the laser beam, a high-reflection mirror to produce a large output by collecting the laser beam, a collimator lens to guide the laser beam to an optical fiber and a protection filter to block reflected laser light that might damage the LD chip. The cylindrical lenses used in a semiconductor laser module are defined as FACs (fast axis collimators) and SACs (slow axis collimators) and are attached to the system module to control the shape of the laser beam. The FAC lens and the SAC lens are made of a glass material to protect the lenses from thermal deformation. In addition, they have aspheric shapes to improve optical performances. This paper presents a mold core grinding process for an asymmetrical aspheric lens and a GMP (glass molding press), what can be used to make aspheric cylindrical lenses for use as FACs or SACs, and a protection filter made by using IAD (ion-beam-assisted deposition). Finally, we developed the aspheric cylindrical lenses and the protection filter for a 10-W semiconductor laser module.

Monochromatic x-ray radiography of laser-driven spherical targets using high-energy, picoseconds LFEX laser

Science.gov (United States)

Sawada, Hiroshi; Fujioka, S.; Lee, S.; Arikawa, Y.; Shigemori, K.; Nagatomo, H.; Nishimura, H.; Sunahara, A.; Theobald, W.; Perez, F.; Patel, P. K.; Beg, F. N.

2015-11-01

Formation of a high density fusion fuel is essential in both conventional and advanced Inertial Confinement Fusion (ICF) schemes for the self-sustaining fusion process. In cone-guided Fast Ignition (FI), a metal cone is attached to a spherical target to maintain the path for the injection of an intense short-pulse ignition laser from blow-off plasma created when nanoseconds compression lasers drive the target. We have measured a temporal evolution of a compressed deuterated carbon (CD) sphere using 4.5 keV K-alpha radiography with the Kilo-Joule, picosecond LFEX laser at the Institute of Laser Engineering. A 200 μm CD sphere attached to the tip of a Au cone was directly driven by 9 Gekko XII beams with 300 J/beam in a 1.3 ns Gaussian pulse. The LFEX laser irradiated on a Ti foil to generate 4.51 Ti K-alpha x-ray. By varying the delay between the compression and backlighter lasers, the measured radiograph images show an increase of the areal density of the imploded target. The detail of the quantitative analyses to infer the areal density and comparisons to hydrodynamics simulations will be presented. This work was performed with the support and under the auspices of the NIFS Collaboration Research program (NIFS13KUGK072). H.S. was supported by the UNR's International Activities Grant program.

Ultrafast optical switching in three-dimensional photonic crystals

OpenAIRE

Mazurenko, D.A.

2004-01-01

The rapidly expanding research on photonic crystals is driven by potential applications in all-optical switches, optical computers, low-threshold lasers, and holographic data storage. The performance of such devices might surpass the speed of traditional electronics by several orders of magnitude and may result in a true revolution in nanotechnology. The heart of such devices would likely be an optical switching element. This thesis analyzes different regimes of ultrafast all-optical switchin...

Aurora project: optical design for a kilojoule class KrF laser

International Nuclear Information System (INIS)

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

1985-01-01

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

Creating large second-order optical nonlinearity in optical waveguides written by femtosecond laser pulses in boro-aluminosilicate glass

Science.gov (United States)

An, Hong-Lin; Arriola, Alexander; Gross, Simon; Fuerbach, Alexander; Withford, Michael J.; Fleming, Simon

2014-01-01

The thermal poling technique was applied to optical waveguides embedded in a commercial boro-aluminosilicate glass, resulting in high levels of induced second-order optical nonlinearity. The waveguides were fabricated using the femtosecond laser direct-write technique, and thermally poled samples were characterized with second harmonic optical microscopy to reveal the distribution profile of the induced nonlinearity. It was found that, in contrast to fused silica, the presence of waveguides in boro-aluminosilicate glass led to an enhancement of the creation of the second-order nonlinearity, which is larger in the laser written waveguiding regions when compared to the un-modified substrate. The magnitude of the nonlinear coefficient d33 achieved in the core of the laser-written waveguides, up to 0.2 pm/V, was comparable to that in thermally poled fused silica, enabling the realization of compact integrated electro-optic devices in boro-aluminosilicate glasses.

Beam propagation considerations in the Aurora laser system

International Nuclear Information System (INIS)

Rosoche, L.A.; Mc Leod, J.; Hanlon, J.A.

1987-01-01

Aurora is a high-power KrF laser system now being constructed for inertial confinement fusion (ICF) studies. It will use optical angular multiplexing and serial amplification by electron-beam-driven KrF amplifiers to deliver a stacked, multikilojoule 5-ns-duration laser pulse to ICF targets. The requirements of angular multiplexing KrF lasers at the multikilojoule level dictate path lengths on the order of 1 km. The inherent complicated path crossings produced by angular multiplexing and pulse stacking do not allow isolation of individual beam lines, so the optical quality of the long beam paths must be controlled. Propagation of the 248-nm light beams over long paths in air is affected by scattering, absorption thermal gradients and turbulence, beam alignment, and control and optical component figure errors

Optical Phase Recovery and Locking in a PPM Laser Communication Link

Science.gov (United States)

Aveline, David C.; Yu, Nan; Farr, William H.

2012-01-01

Free-space optical communication holds great promise for future space missions requiring high data rates. For data communication in deep space, the current architecture employs pulse position modulation (PPM). In this scheme, the light is transmitted and detected as pulses within an array of time slots. While the PPM method is efficient for data transmission, the phase of the laser light is not utilized. The phase coherence of a PPM optical signal has been investigated with the goal of developing a new laser communication and ranging scheme that utilizes optical coherence within the established PPM architecture and photon-counting detection (PCD). Experimental measurements of a PPM modulated optical signal were conducted, and modeling code was developed to generate random PPM signals and simulate spectra via FFT (Fast Fourier Transform) analysis. The experimental results show very good agreement with the simulations and confirm that coherence is preserved despite modulation with high extinction ratios and very low duty cycles. A real-time technique has been developed to recover the phase information through the mixing of a PPM signal with a frequency-shifted local oscillator (LO). This mixed signal is amplified, filtered, and integrated to generate a voltage proportional to the phase of the modulated signal. By choosing an appropriate time constant for integration, one can maintain a phase lock despite long dark times between consecutive pulses with low duty cycle. A proof-of-principle demonstration was first achieved with an RF-based PPM signal and test setup. With the same principle method, an optical carrier within a PPM modulated laser beam could also be tracked and recovered. A reference laser was phase-locked to an independent pulsed laser signal with low-duty-cycle pseudo-random PPM codes. In this way, the drifting carrier frequency in the primary laser source is tracked via its phase change in the mixed beat note, while the corresponding voltage feedback

Amplified spontaneous emission and laser emission from a high optical-gain medium of dye-doped dendrimer

International Nuclear Information System (INIS)

Yokoyama, Shiyoshi; Nakahama, Tatsuo; Mashiko, Shinro

2005-01-01

We measured the amplified spontaneous emission and laser emission from high-gain media of laser-dye encapsulated dendrimers. A highly branched poly(amidoamine) (PAMAM-OH) dendrimer formed a guest-host complex with a conventional laser-dye (DCM), resulting in a high optical-gain. Of particular note was the appearance of a laser threshold, above which a super-narrowed laser spectrum was observed, although laser feedback was caused without any mirror cavity devices. The optical feedback was attributed to spatial confinement of the light due to gain guiding under optical excitation. The laser spectrum clearly indicated a resonant laser-mode with a spectrum linewidth of less than 0.1 nm. This order of spectrum narrowing is comparable to that seen in the laser emission from ordinary laser devices

Development of High-Gradient Dielectric Laser-Driven Particle Accelerator Structures