A.N. Mal'shakov

Compensation of thermally induced modal distortions in Faraday isolators

Two methods of compensation of thermal lensing in high-power terbium gallium garnet (TGG) Faraday isolators have been investigated in detail: compensation by means of an ordinary negative lens and compensation using FK51 Schott glass possessing a negative dn/dT. Key thermooptic constants for TGG crystals and FK51 glass were measured. We find that the contribution of the photoelastic effect to the total thermal lens cannot be neglected for either TGG or FK51. We define a figure of merit for compensating glass and show that for FK51, an ordinary negative lens with an optimal focus is more efficient, but requires physical repositioning of the lens for different laser powers. In contrast, the use of FK51 as a compensating element is passive and works at any laser power, but is less effective than simple telescopic compensation. The efficiency of adaptive compensation can be considerably enhanced by using a compensating glass with figure of merit more than 50, a crystal with natural birefringence or gel.

1 petawatt OPCPA laser in Russia: Status and expectations

In spite of the fact that the petawatt level has been attained quite a time ago [ 1 ], only a few petawatt facilities are available worldwide. One of them, a 056 PW OPCPA facility, was created at the Institute of Applied Physics in 2006 [ 2 ]. The main OPCPA merit is a possibility of power scaling. In the current work we report construction of still another Russian OPCPA-based laser complex.

Use of self-focusing effect for measurements of small (less than A/3000) wavefront distortions

Results of using the self-focusing effect in Kerr liquids for measurements of small wavefront distortions of laser radiation transmitted through a transparent optical sample are presented. An experimental prototype of a new device, a Scanning Nonlinear Hartmann Sensor, is described.

Initial experiments on electron acceleration driven by OPCPA laser

Experiments on electron and ion acceleration using powerful laser radiation have been successfully carried out lately. A possibility to get high electron energies amounting hundreds of MeV and even GeV, the electron energy spread being small and the angular spectrum being narrow, makes laser-driven accelerators interesting and promising for many applications in atomic physics, medicine, etc.

Tabletop 300J 1ns Nd:glass laser with 3 diffraction-limited beam divergence

This paper describe tabletop 300J Nd:glass laser is used to pump a broadband chirped pulse optical parametric amplifier and constitutes part of a 0,5 PW femtosecond setup. Beam divergence was measured in the focal plane of a non-aberration objective with a focal distance of 3m. The measurements showed that 90% of beam energy was concentrated in an angle 35 murad. The second harmonic generator is made of a 22-mm-long KD*P crystal (oee type). The second harmonic energy was up to 190J.

Tabletop 200 TW 45 fs laser based on optical parametric chirped pulse amplification

200TW peak power at 45 fs pulse duration (910 nm central wavelength) has been achieved experimentally using three optical parametrical amplifiers based on KD*P crystals. Energy conversion efficiency of the final amplifier stage was 25%.

A compact 100 J/100 GW pump laser for broadband chirped pulse optical parametric amplifier

The described laser system comprises a Nd:YLF pulse-repetitive laser, a tabletop 100 J pulsed Nd:glass laser and a beam shaper. The system is synchronized with a femtosecond laser and used as pump of optical parametric amplifier.

Front-end system for multi-petawatt laser based on non-generaive optical parametric amplification in KD*P

In a three-cascade optical parametric chirp pulse amplifier based on KD*P crystal the pulse energy was 100mJ at 911nm wavelength. Adding two more parametrical amplifiers (100mm and 300mm diameter) will result in a multipetawatt laser.

Construction of the prototype of an optical system for measurement of small wavefront distortion of laser radiation in optical elements: proposal for the ISTC project

Technique testing of quality the transparent component of optical devices with application of self-focusing effect is offered. In measurement of small wavefront distortions a method of comparison of laser beam parameters before and after passage of a tested optical element is used. With the purpose of increase of sensitivity it is offered for overcoming negative diffraction action to use self-focusing effect of probe beam. Application of self-focusing effect allows to reach sensitivity no less than (lambda) /600 and in future up to (lambda) /3000. On simple samples experimental checks of a method are made.

Pulse-shape control in phase conjugate lasers

A simple quality model of stimulated Brillouin scattering of focused beams is suggested which allows us to quite accurately describe the shape of a Stocks pulse. For a case of totally overlapping pulses we have theoretically and experimentally investigated peculiarities of laser pulse deformations under amplification in two-pass and four-pass amplifiers with a phase-conjugate mirror when pump and spontaneous emission are neglected. Approximate formulas for determination of output pulse duration and duration of the pulse leading front are obtained. Parameters permitting to more effectively control the output pulse shape are found. We also suggest some ways to change the duration of a laser pulse without any significant change in its energy.