Investigation of possibility to improve the efficiency of adaptive system of “Luch” facility
S.G. Garanin, A.I. Golubev, V.M. Povyshev, F.A. Starikov, R.A. Shnyagin
Federal State Unitary Enterprise, Russian Federal Nuclear Center — All-Russian Research Institute of Experimental Physics', Sarov, Nizhny Novgorod region, Russia,
37, pr. Mira, 607188, Sarov, Nizhny Novgorod region, Russia
Keywords: adaptive mirror, phase correction of laser beam, optical aberrations, stochastic parallel gradient algorithm, laser irradiation
Abstract
The methods of the control of a wide-aperture 61-element adaptive mirror implemented at the “Luch” facility are numerically investigated. These methods are based on the stochastic parallel gradient (SPG) algorithm and the least-squares approach (LSA) for control voltage calculation. The capability of the adaptive mirror is determined regarding to correction of phase aberrations. It is found that SPG algorithm is capable to practically completely realize the potential of the adaptive mirror on the energy focusing. By means of SPG algorithm it is possible to obtain more efficient correction of the laser beam aberrations in comparison with that realized in the experiments under conventional adaptive mirror operation mode based on the phase measurement by a wavefront sensor. A combined method (based on SPG algorithm and LSA) of adaptive mirror control is proposed. By means of this method it is possible to obtain the laser energy in diffraction angle at a level of 40% and the Strehl number at a rate of 0.4.
|
