Nikolay Stanislavovich Kazak (b. 29.10.1945, v. Deshchenka, Uzda District, Minsk Region), physicist. Academician of the National Academy of Sciences of Belarus (2003; corresponding member since 2000), Doctor of Physico-Mathematical Sciences (1993).
Scientific works on crystal optics, crystal acoustics and nonlinear optics. He carried out research on the nonlinear conversion of laser radiation in various crystals and experimental geometries with regard to the real parameters of laser radiation. He created a number of highly efficient nonlinear optical frequency converters and other radiation parameters of various types of lasers. Received a powerful smoothly tunable UV radiation by converting the frequency of dye lasers, predicted non-linear-optical effect of generating an alternating electric field. Implemented the method of "nonlinear mirror" to control the spectral, temporal and spatial parameters of the radiation of complex laser systems. He developed nonlinear optical methods for measuring parameters of laser radiation and substances in the UV and IR ranges, a method of passive absorption spectroscopy, IR spectrometers with high spectral brightness based on intracavity up-conversion, methods of controlling ultrasonic beams. He studied the propagation of light and ultrasonic waves near special directions in a crystal and created methods for controlling the spatial parameters of these beams. Investigated various modes of nonlinear-optical frequency conversion of Bessel light beams. Showed the possibility of birth and annihilation of optical vortices in the nonlinear-frequency conversion of these beams. Implemented a method of forming higher order Bessel beams and beams with wave front dislocation using biaxial crystals.
Author of more than 320 scientific papers, 41 inventions.
State Prize of the Republic of Belarus in 2000 for the research of nonlinear optical phenomena and the creation on this basis of new highly efficient sources of laser radiation. The Leninist Komsomol Prize of Belarus in 1978 for the research of laser radiation conversion processes and the development on its basis of high-power coherent light sources with a smooth frequency tuning in the visible, ultraviolet and infrared ranges.
Awarded with the Order of Francisk Skaryna (2002), the Order of Honor (2012).