scholarly journals Adaptive Optical Systems in Air-Based Laser System. Analytical Review. Part 1. Current Status

2019 ◽  
pp. 1-23
Author(s):  
Yu. I. Shanin
Keyword(s):  
Laser Radiation ◽  
Adaptive Optics ◽  
Laser System ◽  
The United States ◽  
High Energy ◽  
Optical Systems ◽  
Current Status ◽  
Powerful Laser ◽  
Optical Elements ◽  
Laser Systems

Aviation-based laser complex is a complex technical object. Among its systems, we analyse only an adaptive optical system and issues related to its performance, and show that the effectiveness of the complex without an adaptive system is small. The analysis was carried out in terms of systems that were developed in the United States.Using the tilt corrector, an adaptive optics provides accurate tracking of the object. A deformable mirror performs correction of higher-order radiation wavefront aberrations caused by atmospheric turbulence for incoming light and outgoing laser radiation. The advantages of onboard laser systems are the beam propagation at the speed of light and the low price of a shot. The disadvantages are that the target should be in line-of-sight and there is a negative influence of the atmosphere. Another negative influences are vibrations of the aircraft and the aero-optical problem because of output radiation. An assured thermal target kill is possible at the range of 3-10 km. A functional kill and suppression are capable at ranges of 102-103 times longer than for the thermal target kill.Among the programs for the development of an onboard laser in the USA, the YAL, ATL and ABL programs are considered. The YAL program is an attempt to intercept short-and medium-range missiles with a powerful laser. The ATL system was to be installed on a heavily armed ground support aircraft. An airborne laser (ABL) is a demonstration of the U.S. Air Force of a high-energy laser system designed to destroy missiles on their boost phase. Over 30 years and several tens of billions of dollars were expended to develop the systems. Unfortunately, all onboard laser development programs have been closed.Experience of the flying laboratories is realized by Cessna Citations and Falcon 10s planes and is relevant, as it gives the chance to estimate adverse effects of aero-optics and vibrations directly in flight.Among the problems that need to be solved when creating adaptive optics for an onboard laser, the following are highlighted:-      loss of compensation capabilities;-      thermal effects of laser radiation on optical elements;-      creation of attenuators and radiation couplers;-    mitigating the negative effects of the onboard platform on radiation;-      operation reliability of the actuators of correction devices;-      technological working off of the uncooled optical elements which are affected by powerful laser radiation.For newly developed aviation-based laser systems, it is necessary to envision the niche in which their use will be most efficient.

High-Energy Laser System with Self-Sustaining Adaptive Optics and Laser Speckle Effect

2016 ◽  
Vol 36 (10) ◽  
pp. 1001001
Author(s):  
贾昱成 Jia Yucheng ◽  
许倩 Xu Qian ◽  
孙建锋 Sun Jianfeng ◽  
曾祥龙 Zeng Xianglong ◽  
刘立人 Liu Liren
Keyword(s):  
Adaptive Optics ◽  
Laser System ◽  
High Energy ◽  
Laser Speckle ◽  
Energy Laser ◽  
High Energy Laser

scholarly journals Using an Adaptive Filtration to Improve Adaptive Optical Systems Performance. Analytical Review

2019 ◽  
pp. 34-60
Author(s):  
Yu. I. Shanin
Keyword(s):  
Wave Front ◽  
Adaptive Optics ◽  
Adaptive Filtering ◽  
Input Signal ◽  
Least Square ◽  
Optical Systems ◽  
Control Algorithms ◽  
Optical Wave ◽  
Adaptive Filtration ◽  
Laser Systems

For adaptive optical systems (AOS) installed in the optical path of aircraft-based laser systems, the presence of changing input light signals is typical. A wave-front sensor processes these signals. The quality of the radiation wave-front correction depends on how well the rapidly changing input signal is received and processed. When dealing with such signals, an adaptive filtration (AF) is used, which allows automatic adaptation to the changing input signal. The adaptive filtration is used in control algorithms for adaptive optical systems.The paper gives a brief theoretical AF background as applied to the AOS. The AF with feedback can be used for the following: a) predictions, b) identification of an unknown system, c) balancing of characteristics, d) disturbance rejection. The AF main point is to control the weighting factors of the input signal, which form the output signal. Under control, the difference between the reference and output signals is minimized. Mathematically, this comes down to defining the global minimum of the objective function. Among the search methods for this minimum, the paper considers the following ones: the Newton's method, the steepest-descent method and its modified version - the least square error method, and the recursive AF algorithm using the least squares criterion. The choice requirements for an adaptive algorithm are formulated.The paper considers direct application of the AF methods in the control algorithms of the AOS used in the airborne laser systems. Analyzes both the works on improving operation of classical AOS control loops (based on the PID-controllers with time-fixed gains) by adding various adaptive devices to the circuit, and the works on direct use of the adaptive filters and their relevant control algorithms. Adaptive filtering has shown the positive results both in suppressing the multiple narrow-band vibrations inherent in the aircraft and in broadband jitter due to the turbulent atmosphere, including the aero-optical wave-front aberrations of laser radiation.For more successful application of the adaptive filtering methods for AOS control, further interpretation and research into capabilities of their practical implementation for specific applications of adaptive optics is required.

scholarly journals The all-diode-pumped laser system POLARIS – an experimentalist’s tool generating ultra-high contrast pulses with high energy

2014 ◽  
Vol 2 ◽  
Author(s):  
Marco Hornung ◽  
Hartmut Liebetrau ◽  
Andreas Seidel ◽  
Sebastian Keppler ◽  
Alexander Kessler ◽  
...  
Keyword(s):  
Laser System ◽  
Laser Pulses ◽  
High Energy ◽  
Current Status ◽  
Temporal Contrast ◽  
Chirped Pulse ◽  
Chirped Pulse Amplification ◽  
Diode Pumped ◽  
Generation Pulse ◽  
Scientific Tool

Abstract The development, the underlying technology and the current status of the fully diode-pumped solid-state laser system POLARIS is reviewed. Currently, the POLARIS system delivers 4 J energy, 144 fs long laser pulses with an ultra-high temporal contrast of $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}5\times 10^{12}$ for the ASE, which is achieved using a so-called double chirped-pulse amplification scheme and cross-polarized wave generation pulse cleaning. By tightly focusing, the peak intensity exceeds $3.5\times 10^{20}\ \mathrm{W\ cm}^{-2}$ . These parameters predestine POLARIS as a scientific tool well suited for sophisticated experiments, as exemplified by presenting measurements of accelerated proton energies. Recently, an additional amplifier has been added to the laser chain. In the ramp-up phase, pulses from this amplifier are not yet compressed and have not yet reached the anticipated energy. Nevertheless, an output energy of $16.6\ \mathrm{J}$ has been achieved so far.

Large-Size Monosectorial Crystal Elements for Powerful Laser Systems

1997 ◽  
Vol 06 (04) ◽  
pp. 467-472 ◽  
Author(s):  
V. I. Bespalov
Keyword(s):  
Crystal Growth ◽  
Nuclear Fusion ◽  
High Rate ◽  
Powerful Laser ◽  
Applied Physics ◽  
Optical Elements ◽  
Growth Technique ◽  
Large Size ◽  
Laser Systems ◽  
Fusion Experiments

The potentialities of fabricating large-size monosectorial crystals for powerful laser systems are discussed. Two types of technologies used for high-rate growth of profiled crystals and some results attained in crystal growth in the Institute of Applied Physics of the Russian Academy of Science are described briefly. It is concluded that the growth technique developed may be used for producing large-size optical elements (about 400 × 400 mm2) for laser systems intended for nuclear fusion experiments.

scholarly journals ASTIGMATISM COMPENSATION IN BLOCK OF TEMPORAL BROADENING OF PULSE FOR PUMP CHANNEL OF HIGH POWER LASER SYSTEM

2020 ◽  
Vol 25 (4) ◽  
pp. 205-212
Author(s):  
Alexei V. Laptev ◽  
◽  
Gleb V. Kuptsov ◽  
Vladimir A. Petrov ◽  
Victor V. Petrov ◽  
...  
Keyword(s):  
Laser System ◽  
Average Power ◽  
High Average Power ◽  
Optimal Parameters ◽  
Power Laser ◽  
Optical Elements ◽  
Laser Amplification ◽  
Laser Systems ◽  
High Power Laser System ◽  
Temporal Broadening

A high peak and high average power femtosecond laser system based on media doped with Yb3+ ions is being developed at the Institute of Laser Physics of the SB RAS. For efficient laser amplification and to avoid optical damage is actually to compensate wave front distortion caused by grating astigmatism in pump channel. Based on theory of propagation of gaussian beam in space and through optical elements the calculation of optimal parameters of two lenses telescope and comparison with experimental data has been performed. The obtained results can be used for decrease of astigmatic effect on beam profile quality in design of laser systems with elements involving astigmatism.

Design of Diffractive Optical Elements for Chromatic Aberration Correction in High-Energy Petawatt Laser System

2010 ◽  
Vol 30 (1) ◽  
pp. 142-146
Author(s):  
谢旭东 Xie Xudong ◽  
朱启华 Zhu Qihua ◽  
周凯南 Zhou Kainan ◽  
张颖 Zhang Ying ◽  
黄小军 Huang Xiaojun
Keyword(s):  
Laser System ◽  
Chromatic Aberration ◽  
High Energy ◽  
Aberration Correction ◽  
Diffractive Optical Elements ◽  
Optical Elements

scholarly journals Ultrashort pulse capability at the L2I high intensity laser facility

2017 ◽  
Vol 5 ◽  
Author(s):  
Gonçalo Figueira ◽  
Joana Alves ◽  
João M. Dias ◽  
Marta Fajardo ◽  
Nuno Gomes ◽  
...  
Keyword(s):  
High Intensity ◽  
Laser System ◽  
Current Status ◽  
Research Centre ◽  
Laser Plasma Interaction ◽  
High Intensity Laser ◽  
Laser Facility ◽  
Laser Systems ◽  
Diode Pumped ◽  
Intensity Laser

The Laboratory for Intense Lasers (L2I) is a research centre in optics and lasers dedicated to experimental research in high intensity laser science and technology and laser plasma interaction. Currently the laboratory is undergoing an upgrade with the goal of increasing the versatility of the laser systems available to the users, as well as increasing the pulse repetition rate. In this paper we review the current status of the laser research and development programme of this facility, namely the upgraded capability and the recent progress towards the installation of an ultrashort, diode-pumped OPCPA laser system.

scholarly journals High energy heavy ion jets emerging from laser plasma generated by long pulse laser beams from the NHELIX laser system at GSI

2005 ◽  
Vol 23 (4) ◽  
pp. 503-512 ◽  
Author(s):  
G. SCHAUMANN ◽  
M.S. SCHOLLMEIER ◽  
G. RODRIGUEZ-PRIETO ◽  
A. BLAZEVIC ◽  
E. BRAMBRINK ◽  
...  
Keyword(s):  
Heavy Ions ◽  
Laser Energy ◽  
Laser System ◽  
Heavy Ion ◽  
Spot Size ◽  
High Energy ◽  
Focal Spot Size ◽  
Laser Systems ◽  
Order Of Magnitude ◽  
Long Pulse

High energy heavy ions were generated in laser produced plasma at moderate laser energy, with a large focal spot size of 0.5 mm diameter. The laser beam was provided by the 10 GW GSI-NHELIX laser systems, and the ions were observed spectroscopically in status nascendi with high spatial and spectral resolution. Due to the focal geometry, plasma jet was formed, containing high energy heavy ions. The velocity distribution was measured via an observation of Doppler shifted characteristic transition lines. The observed energy of up to 3 MeV of F-ions deviates by an order of magnitude from the well-known Gitomer (Gitomer et al., 1986) scaling, and agrees with the higher energies of relativistic self focusing.

FEMTOSECOND LASER-INDUCED DAMAGE OF DIELECTRICS

1999 ◽  
Vol 13 (13) ◽  
pp. 1559-1578 ◽  
Author(s):  
M. LENZNER
Keyword(s):  
Current Knowledge ◽  
Laser System ◽  
Damage Threshold ◽  
Laser Pulses ◽  
Dielectric Materials ◽  
Optical Systems ◽  
Irreversible Damage ◽  
Optical Damage ◽  
Laser Systems ◽  
Laser Induced Damage

Optical damage in non-metals (dielectrics) may severely affect the performance of high-power laser systems as well as the efficiency of optical systems based on nonlinear processes and has therefore been subject to extensive research for some 30 years. The current knowledge of laser-induced optical damage in these materials is reviewed. Emphasis is placed on the recent extension of available experimental data into the femtosecond range. Recent results are presented achieved with a sub-10 fs laser system which explores the limits of time resolution as well as the limit of intensities that a solid can sustain without irreversible damage. It is concluded that sub-10fs laser pulses open up the way to reversible nonperturbative nonlinear optics at intensities greater than 1014 W/cm 2 (slightly below damage threshold) and to nanometer-precision laser ablation (slightly above threshold) in dielectric materials.

scholarly journals Self-pumped SBS effect of high-power super-Gaussian-shaped laser pulses

2015 ◽  
Vol 34 (1) ◽  
pp. 72-79 ◽  
Author(s):  
Yulei Wang ◽  
Xuehua Zhu ◽  
Zhiwei Lu ◽  
Hengkang Zhang
Keyword(s):  
High Power ◽  
Nonlinear Medium ◽  
Brillouin Scattering ◽  
Laser Pulses ◽  
High Energy ◽  
The Self ◽  
Center Frequency ◽  
Stokes Component ◽  
Optical Elements ◽  
Laser Systems

AbstractMost of the high-energy laser systems deliver temporally super-Gaussian-shaped laser pulses. The propagation properties of this kind of pulses in a nonlinear medium are studied in this paper. There is Stokes component in the sideband spectrum of super-Gaussian-shaped pulses, and the frequency difference between the Stokes component and the center frequency is equals to the Brillouin frequency of the nonlinear medium. When the laser is reflected by optical elements in the light path, Stokes component in the reflected light can be amplified by the subsequent part of the laser pulse and excite stimulated Brillouin scattering (self-pumped SBS). The self-pumped SBS is studied theoretically and experimentally, and the experimental results agreed well with the calculated results. The simulation results show that lower-order super-Gaussian-shaped pulses are more suitable for suppressing the self-pumped SBS and of great benefit to the energy delivering of the high-power laser pulses. To the best of our knowledge, this is the first time to experimentally demonstrate the self-pumped SBS of high-power super-Gaussian-shaped laser pulses.

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