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Дисперсионные линии задержки для сверхмощных лазерных систем
Application of acousto-optic dispersive delay lines makes it possible to solve problems of shape correction of ultra-short laser pulses in high-power laser systems designed for controlled inertial fusion. Creation of high-power femtosecond laser systems proved to be one of the breakthroughs in the science of physics at the turn of the century. In recent years the development of femtosecond laser systems shows evidence of a swift progress. In the leading international laboratories the peak laser pulse power ranges up to the petawatt level which exceeds a hundred times the combined power of all energy sources on earth. As of now, laser systems of multi-petawatt power are under development. In some laboratories there has been obtained a stable lasing of femtosecond emission containing only 1-2 periods. Such laser sources will furnish a way in the nearest future to carry out fundamental research in the field of physics of super-high energy density. The recent line of investigation is the initiation of nuclear reaction, generation of strong X-ray emission, acceleration of electrons and ions, as well as creation of charged particles laser accelerators using the action of petawatt optical impulses on gas and solid-state targets. This opens up new avenues for low-scale low-contrast X-ray tomography, hadron cancer therapy, protonography, etc. The quality of pulses substantially depends on uncompensated higher-order dispersions and deformation of emission spectrum in the amplifier. If to use in a laser system a special dispersive device compensating the available higher-order dispersions and introduce spectrum distortions in optical channel of the system, by way of adaptive action on spectral amplitudes and phases of the femtosecond pulse, it is possible to cut down the duration of the compensated impulse, to enhance the contrast and suppress the pre-pulses. The solution of this kind makes it possible to raise the peak power of femtosecond emission not by increasing the power of laser system but by shortening the impulse through changing the spectral phase in an orderly fashion. On the other hand, an independent control of amplitude of pulse spectrum gives an opportunity to form pulses of necessary shape expressly designed for optimal conditions whereby the amplification of subsequent cascades takes place. To-day in modern laser installations different methods of controlling the spectrum phase are in use, namely, chirped mirrors, liquid-crystal spatial light modulators, and devices of wave electronics: adaptive delay lines on the base of acousto-optic effect. Experiences in operating high-power laser systems pointed to the fact that delay lines on the base of acousto-optic effect offer a number of advantages, such as the linear geometry without close correspondence with stretcher’s geometry, the continuity of phase control, the possibility of independent control over not only the phase but spectrum amplitude as well, the high-speed adaptive response. Finally, acousto-optic delay lines possess optical memory stemming from the finite velocity of propagation of the controlled sound field in crystals. That is a necessary condition for creating intellectual systems. Thanks to these advantages the acousto-optic delay line has won the competition with other devices.

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Director of Acousto-optical Research Center, Ph.D.
Vice-director of Acousto-optical Research Center, Ph.D.
Senior researcher, Ph.D.
Senior researcher, Ph.D.
Leading researcher, Ph.D.

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