Y. V. Lebiadok

High-performance LD-pumped solid-state lasers for range finding and spectroscopy

Power, special and temporal characteristics of high–performance advanced LD–pumped solid–state laser systems emitting in the spectral ranges of 1064, 1535 and 1570 (fundamental modes) as well as 266, 355 and 532 nm (fourth, third and second harmonics) are discussed. The ways for further improvement of those laser systems are proposed. In addition, the problem of optimization of the pump unit based on the powerful laser diode arrays (LDAs) is analyzed. The effect of the LDA internal optical loss on the amplified spontaneous emission flux value developed within the LDA active layer is considered in detail.

Measurement of the water content in oil and oil products using IR light-emitting diode–photodiode optrons

The feasibility of using light-emitting devices, the radiation spectrum of which has maxima at wavelengths of 1.7, 1.9, and 2.2 μm for determining the water concentration in oil and oil products (gasoline, kerosene, diesel fuel) has been demonstrated. It has been found that the measurement error can be lowered if (i) the temperature of the light-emitting diode is maintained accurate to 0.5–1.0°C, (ii) by using a cell through which a permanently stirred analyte is pumped, and (iii) by selecting the repetition rate of radiation pulses from the light-emitting diodes according to the averaging time. A meter of water content in oil and oil products has been developed that is built around IR light-emitting device–photodiode optrons. This device provides water content on-line monitoring accurate to 1.5%.

Influence of vacancies on GaN/AlN interface characteristics

The results of the influence of point defects (vacancy with interstitial atom) on the GaN/AlN heterointerface is presented. It was ascertained that presence of Al atom vacancy in the heterointerface leads to the contacting layer atoms rearrangement. The presence of N atom vacancy does not influence on the contacting Ga and Al layers intermixing.

Nitrogen vacancies in the GaN/AlN heterointerface

The results of calculation of nitrogen vacancy geometry in GaN/AlN heterointerface and its comparison with experimental data are discussed in the paper. The methods of calculation of point defects geometry in the GaN/AlN interface within the frameworks of self-consistent field and density functional theory are compared.

Active vision systems based on powerful laser diode matrixes: design peculiarities and vision range

The present paper is aimed to development of the powerful illumination module based on powerful AlGaAs/GaAs laser diode matrix with short laser pulses, high repetition rate, given radiation divergence characteristics and stabilized parameters. Developed modification of the powerful illumination module gives the chance to realize powerful pulse laser radiation on the wavelength of 846 nm with the effective form of the laser pulse, wide range of duration from tens to hundreds of nanoseconds and the frequency of repetition rate of pulses up to 10 kHz in the set space angle of radiation 27° × 8°.

Efficiency of laser-diode-array side pumping of a passively Q-switched erbium laser

A method of modelling the conditions for side pumping a passively Q-switched erbium laser with linear laser-diode arrays is proposed that makes it possible to determine the most efficient geometry for the placement of the linear arrays relative to the active element, taking into account the characteristics of not only the diode arrays and the active element, but also of the optical cavity that is used. The results of the modelling make it possible to choose the distance between the linear arrays and the active element and the allowable shift of the linear arrays relative to each other, and this optimizes the matching of the excitation and lasing conditions. The proposed optimization method takes into account the divergence and polarization of the radiation of the diode arrays, the geometrical and optical properties of the active element, and the configuration of the lasing mode. The theoretical results of the modelling are compared with the experimental data.

Multiwave LD-pumped solid-state lasers for aerosol lidar application

The work is devoted to the development and creation of the powerful all solid-state air-cooled multiwave Nd:YAG laser integrated with the output telescope system and to the development of the LD-pumped solid-state source with the extremely narrow lasing linewidth. The laser sources are meant for operation with the multiwave aerosol LIDAR (atmosphere probing altitude is up to 40 km).