GARPUN-MTW: A hybrid Ti:Sapphire/KrF laser facility for simultaneous amplification of subpicosecond/nanosecond pulses relevant to fast-ignition ICF concept

The first stage of the petawatt excimer laser project started at the P.N. Lebedev Physical Institute, implements a development of multiterawatt hybrid GARPUN-MTW laser facility for generation of ultra-high intensity subpicosecond ultraviolet (UV) laser pulses. Under this project, a multi-stage e-beam-pumped 100-J, 100-ns GARPUN KrF laser was upgraded with a femtosecond Ti:Sapphire front-end, to produce combined subpicosecond/nanosecond laser pulses with variable time delay. Attractive possibility to amplify simultaneously short and long pulses in the same large-scale KrF amplifiers is analyzed with regard to the fast-ignition, inertial confinement fusion problem. Detailed description of hybrid laser system is presented with synchronized KrF and Ti:Sapphire master oscillators. Based on gain and absorption measurements at GARPUN amplifier and numerical simulations with a quasi-stationary code, we are predicting that 1.6 J can be obtained in a short pulse at hybrid GARPUN-MTW Ti:Sapphire/KrF laser facility, combined with several tens of joules in nanosecond pulse. Amplified spontaneous emission, which is responsible for the pre-pulse formation on a target, was also investigated: its acceptable level can be provided by properly choosing staged gain or loading the amplifiers by quasi-steady laser radiation. Fluorescence and transient absorption spectra of Ar/Kr/F2 mixtures conventionally used in KrF amplifiers were recorded to find out the possibility for femtosecond pulse amplification at the broadband Kr2F (42Γ → 1,2 2Γ) transition, which benefits in 100 times higher saturation energy density than for KrF (B → X) transition.

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An overview of Aurora: a multi-kilojoule KrF laser system for inertial confinement fusion

Laser and Particle Beams ◽

10.1017/s0263034600001622 ◽

1986 ◽

Vol 4 (1) ◽

pp. 55-70 ◽

Cited By ~ 28

Author(s):

Louis A. Rosocha ◽

Pleas S. Bowling ◽

Michael D. Burrows ◽

Michael Kang ◽

John Hanlon ◽

...

Keyword(s):

Inertial Confinement Fusion ◽

Large Scale ◽

Short Pulse ◽

Laser System ◽

Laser Pulses ◽

Inertial Confinement ◽

Laser Amplifiers ◽

Krf Laser ◽

Confinement Fusion ◽

Laser Systems

Aurora is a short-pulse high-power krypton-fluoride laser system that serves as an end-to-end technology demonstration prototype for large-scale ultraviolet laser systems of interest for short wavelength inertial confinement fusion (ICF) studies. The system is designed to employ optical angular multiplexing and serial amplification by electron-beam-driven KrF laser amplifiers to deliver 248 nm, 5-ns duration multi-kilojoule laser pulses to ICF targets using a beam train of approximately 1 km in length.In this paper, we will discuss the goals for the system and summarize the design features of the major system components: front-end lasers, amplifier train, optical train, and the alignment and controls systems.

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Target alignment in the Shen-Guang II Upgrade laser facility

High Power Laser Science and Engineering ◽

10.1017/hpl.2018.4 ◽

2018 ◽

Vol 6 ◽

Cited By ~ 2

Author(s):

Lei Ren ◽

Ping Shao ◽

Dongfeng Zhao ◽

Yang Zhou ◽

Zhijian Cai ◽

...

Keyword(s):

Inertial Confinement Fusion ◽

Short Pulse ◽

Three Dimensional ◽

Nanosecond Laser ◽

Alignment Error ◽

Inertial Confinement ◽

Pulse Beam ◽

Rotation Sensor ◽

Confinement Fusion ◽

Laser Facility

The Shen-Guang II Upgrade (SG-II-U) laser facility consists of eight high-power nanosecond laser beams and one short-pulse picosecond petawatt laser. It is designed for the study of inertial confinement fusion (ICF), especially for conducting fast ignition (FI) research in China and other basic science experiments. To perform FI successfully with hohlraum targets containing a golden cone, the long-pulse beam and cylindrical hohlraum as well as the short-pulse beam and cone target alignment must satisfy tight specifications (30 and $20~\unicode[STIX]{x03BC}\text{m}$ rms for each case). To explore new ICF ignition targets with six laser entrance holes (LEHs), a rotation sensor was adapted to meet the requirements of a three-dimensional target and correct beam alignment. In this paper, the strategy for aligning the nanosecond beam based on target alignment sensor (TAS) is introduced and improved to meet requirements of the picosecond lasers and the new six LEHs hohlraum targets in the SG-II-U facility. The expected performance of the alignment system is presented, and the alignment error is also discussed.

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Modeling of pulsed laser ablation of aluminum under the action of infrared nanosecond laser pulses

EPJ Web of Conferences ◽

10.1051/epjconf/201919600020 ◽

2019 ◽

Vol 196 ◽

pp. 00020

Author(s):

Nikolay Rubtsov ◽

Victor Bessmeltsev ◽

Maksim Grishin

Keyword(s):

Pulsed Laser ◽

Pulsed Laser Ablation ◽

Laser Pulses ◽

Ablation Depth ◽

Aluminum Surface ◽

Nanosecond Laser ◽

Ablation Process ◽

Nanosecond Pulses ◽

Nanosecond Laser Pulses ◽

Plasma Shielding

The paper presents the results of numerical simulation of aluminum ablation process that is caused by a series of incident nanosecond pulses on a wavelength λ=1064 nm. The mechanism of normal evaporation and the effect of plasma shielding were taken into account. As a result of mathematical modeling the ablation depth was obtained. It is shown that plasma shielding reduces the effectiveness of ablation process much more than cooling of the aluminum surface between pulses.

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Femtosecond, picosecond, and nanosecond laser microablation: Laser plasma and crater investigation

Laser and Particle Beams ◽

10.1017/s0263034602201093 ◽

2002 ◽

Vol 20 (1) ◽

pp. 67-72 ◽

Cited By ~ 56

Author(s):

A. SEMEROK ◽

B. SALLÉ ◽

J.-F. WAGNER ◽

G. PETITE

Keyword(s):

Laser Ablation ◽

Theoretical Models ◽

Laser Pulses ◽

Femtosecond Laser Pulses ◽

Laser Beams ◽

Limiting Factors ◽

Nanosecond Laser ◽

Ablation Efficiency ◽

Nanosecond Pulses ◽

Focused Laser Beams

Crater shapes and plasma plume expansion in the interaction of sharply focused laser beams (10 μm waist diameter, 60 fs–6 ns pulse duration) with metals in air at atmospheric pressure were studied. Laser ablation efficiencies and rates of plasma expansion were determined. The best ablation efficiency was observed with femtosecond laser pulses. It was found that for nanosecond pulses, the laser beam absorption, its scattering, and its reflection in plasma were the limiting factors for efficient laser ablation and precise material sampling with sharply focused laser beams. The experimental results obtained were analyzed with relation to different theoretical models of laser ablation.

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Generation of shock waves in dense plasmas by high-intensity laser pulses

Nukleonika ◽

10.1515/nuka-2015-0056 ◽

2015 ◽

Vol 60 (2) ◽

pp. 193-198 ◽

Cited By ~ 2

Author(s):

John Pasley ◽

I. A. Bush ◽

Alexander P. L. Robinson ◽

P. P. Rajeev ◽

S. Mondal ◽

...

Keyword(s):

Shock Waves ◽

Laser Plasma ◽

Inertial Confinement Fusion ◽

Laser Pulses ◽

Fast Ignition ◽

Intense Laser ◽

Inertial Confinement ◽

Relative Significance ◽

Wide Range ◽

Confinement Fusion

Abstract When intense short-pulse laser beams (I > 1022 W/m2, τ < 20 ps) interact with high density plasmas, strong shock waves are launched. These shock waves may be generated by a range of processes, and the relative significance of the various mechanisms driving the formation of these shock waves is not well understood. It is challenging to obtain experimental data on shock waves near the focus of such intense laser–plasma interactions. The hydrodynamics of such interactions is, however, of great importance to fast ignition based inertial confinement fusion schemes as it places limits upon the time available for depositing energy in the compressed fuel, and thereby directly affects the laser requirements. In this manuscript we present the results of magnetohydrodynamic simulations showing the formation of shock waves under such conditions, driven by the j × B force and the thermal pressure gradient (where j is the current density and B the magnetic field strength). The time it takes for shock waves to form is evaluated over a wide range of material and current densities. It is shown that the formation of intense relativistic electron current driven shock waves and other related hydrodynamic phenomena may be expected over time scales of relevance to intense laser–plasma experiments and the fast ignition approach to inertial confinement fusion. A newly emerging technique for studying such interactions is also discussed. This approach is based upon Doppler spectroscopy and offers promise for investigating early time shock wave hydrodynamics launched by intense laser pulses.

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Development of high-performance KrF and Raman laser facilities for inertial confinement fusion and other applications

Laser and Particle Beams ◽

10.1017/s0263034600004936 ◽

1993 ◽

Vol 11 (2) ◽

pp. 331-346 ◽

Cited By ~ 6

Author(s):

M.J. Shaw ◽

B. Edwards ◽

G.J. Hirst ◽

C.J. Hooker ◽

M.H. Key ◽

...

Keyword(s):

Power Systems ◽

Inertial Confinement Fusion ◽

High Performance ◽

Short Pulse ◽

High Reliability ◽

Laser System ◽

Raman Laser ◽

Current Status ◽

Inertial Confinement ◽

Laser Amplifiers

This article describes the current status of the KrF development programme based on the Sprite laser system at the Rutherford Appleton Laboratory. High reliability and high shot rate have been demonstrated. Using a unique KrF-pumped Raman laser architecture, beam brightness exceeding 2×1019 Wcm-2 sterad-1 giving a focussed intensity >5 ×1017 Wcm-2 has been achieved. The development of transform-limited short-pulse oscillators is shown to be of importance in avoiding spectral broadening in air propagation of high-intensity beams. Beam smoothing of KrF beams in a multiplexed configuration has been demonstrated for the first time. The technique of echelon-free induced spatial incoherence has been shown to produce smooth intensity distributions in the far field, which remain essentially unchanged on amplification. The development of pulsed-power systems capable of exciting multikilojoule laser amplifiers for the next phase of development, the Supersprite system, is briefly discussed.

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Лазерно-индуцированный графен на полиимидной пленке: наблюдение эффекта увлечения

Письма в журнал технической физики ◽

10.21883/pjtf.2020.09.49375.18152 ◽

2020 ◽

Vol 46 (9) ◽

pp. 51

Author(s):

К.Г. Михеев ◽

Р.Г. Зонов ◽

Д.Л. Булатов ◽

А.Е. Фатеев ◽

Г.М. Михеев

Keyword(s):

Continuous Wave ◽

Graphene Film ◽

Laser Pulses ◽

Wavelength Dependence ◽

Polyimide Film ◽

Film Structure ◽

Laser Generation ◽

Nanosecond Laser ◽

Nanosecond Pulses ◽

Wide Range

Porous graphene film structures were produced by irradiation of polyimide film with focused continuous wave CO2 laser. Generation of nanosecond pulses of photocurrent was observed in the obtained structures upon excitation by nanosecond laser pulses in a wide range of wavelengths. It is shown that the photocurrent linearly increases with pulsed laser power and its dependence on the angle of light incidence on the film structure is symmetric about the origin. Wavelength dependence of light-to-photocurrent conversion coefficient was measured. The obtained results are explained by photon-drag effect photocurrent generation.

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Enhancement of nonlinear optical property in ZnS PVA films due to self-assembly

Journal of Nonlinear Optical Physics & Materials ◽

10.1142/s0218863515500204 ◽

2015 ◽

Vol 24 (02) ◽

pp. 1550020 ◽

Cited By ~ 1

Author(s):

S. Mathew ◽

Manu Vaishak ◽

Boni Samuel ◽

T. M. Libish ◽

P. Radhakrishnan ◽

...

Keyword(s):

Thin Film ◽

Thin Films ◽

Self Assembly ◽

Second Harmonic ◽

Laser System ◽

Laser Pulses ◽

Saturable Absorption ◽

Nanosecond Laser ◽

Harmonic Intensity ◽

Visible Luminescence

Nanostructured zinc sulfide ( ZnS ) thin films were synthesized in polyvinyl alcohol matrix by chemical bath deposition and self-assembly techniques. ZnS nanostructured thin films show second harmonic generation (SHG) under irradiation with a pico-second Nd :YAG laser system and the second harmonic intensity is higher for self-assembled nanotree like structured ZnS thin film in comparison with that from chemical bath deposited thin film. Under nanosecond laser pulses, thin films possess good saturable absorption behavior. The optical bandgap and visible luminescence also get enhanced.

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Laser performance of the SG-III laser facility

High Power Laser Science and Engineering ◽

10.1017/hpl.2016.20 ◽

2016 ◽

Vol 4 ◽

Cited By ~ 61

Author(s):

Wanguo Zheng ◽

Xiaofeng Wei ◽

Qihua Zhu ◽

Feng Jing ◽

Dongxia Hu ◽

...

Keyword(s):

Inertial Confinement Fusion ◽

Laser System ◽

Power Balance ◽

Inertial Confinement ◽

Fusion Research ◽

Laser Performance ◽

Laser Driver ◽

Confinement Fusion ◽

Laser Facility ◽

Better Than

SG-III laser facility is now the largest laser driver for inertial confinement fusion research in China. The whole laser facility can deliver 180 kJ energy and 60 TW power ultraviolet laser onto target, with power balance better than 10%. We review the laser system and introduce the SG-III laser performance here.

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