A scheme of a high-power Cr:LiSAF laser operating in active Q-switching mode with a Pockels cell is developed. A method for shortening the laser pulse duration and increasing the peak power by means of intracavity transverse mode selection using an aperture diaphragm and external feedback with Bragg grating is proposed. As a result, the duration of the laser pulse was 19 ns and the pulse energy of 7.7 mJ, which corresponds to 0.41 MW of peak power at the central wavelength of 830 nm. The laser wavelength tuning was also adjusted in the range of 825–865 nm with a width of 2 nm. The results of the research obtained in this work will serve as a basis for the development of new systems for spectrometry for environmental monitoring of the atmosphere using the differential optical absorption spectroscopy method.

Non-contact, non-destructive testing of surface microgeometry plays a key role in such industries as microelectronics, additive manufacturing, and precision engineering. This paper presents the development and experimental testing of a digital holographic system based on a low-coherence laser diode operating at two close wavelengths, designed to measure height differences in the micrometer range. The method is based on a Michelson interferometer and reconstruction of the complex amplitude of the object wave, which allows phase measurements with subsequent phase conversion into heights. The tests were carried out on micrometer roughness standards with a trapezoidal profile with a groove depth from 24.5 μm to 100 μm and a profile width from 65 μm to 150 μm, as well as on reference strokes with a width from 25 to 200 μm. The obtained data demonstrate the possibility of three-dimensional and two-dimensional visualization of the objects under study with a relative error in height from 5.3% to 11.6% and in width up to 18.6%. It is shown that the system allows reliable measurement of defects of metal surfaces in the range from 25 to 100 μm both vertically and horizontally. Thus, the developed method can be used for high-precision, non-destructive testing in a wide range of technological tasks.

В статье дан краткий обзор методов записи объемных голографических решеток Брэгга используемых в качестве оптических элементов для управления спектром излучения мощных импульсных твердотельных лазеров. Рассмотрены регистрирующие среды голографических решеток Брэгга (галогенидосеребряные эмульсии, слои хромированного желатина, кристалл ниобата лития (LiNbO3) и фототерморефрактивное стекло). Представлены схемы записи Ллойда, Майкельсона и Тальбота. Описаны требования, предъявляемые к пространственной стабильности лазерного излучения, и приведена методика их контроля. Приведены экспериментальные результаты процесса записи пропускающих решеток Брэгга в различных твердотельных материалах. Определен порог поверхностной лучевой стойкости фототерморефрактивного стекла путем регистрации пробоя поверхности решетки. Доказана возможность использования решетки в мощных импульсных лазерах.