M. A. Shchemelev

Spatial and polarization properties of the output beam of an ytterbium-erbium laser with transverse diode pumping

The propagation parameter M2 of the beam of an ytterbium-erbium glass laser with transverse diode pumping has been experimentally investigated for various cavity configurations. The polarization characteristics of the laser radiation are presented for cases in which the active medium is excited by two and four linear laser-diode arrays.

Point defects and amplification in active layers of InGaAs/AlGaAs heterostructures

The energy levels of gallium and arsenic vacancies as well as silicon impurities in the band gap of InxGa1 − x As have been found as functions of the indium content. The effect of defects on the lasing output power and on the optimal reflection coefficient of output mirrors of laser diode arrays (LDAs) based on the In0.11Ga0.89As/AlGaAs heterostructures has been estimated. It has been shown that the lasing output power of LDAs whose active level contains defects with deep energy levels in the band gap is substantially lower (with other conditions being the same) than that of LDAs with shallow level defects in their active layers.

High-power optical parametric oscillator based on a high-pulse repetition rate, master Nd : KGW laser

An optical scheme of an optical parametric oscillator with a master laser based on an Nd : KGW active element excited by two orthogonally oriented diode side pump modules is proposed to form radiation pulses with energies above 30 mJ and a repetition rate of 1 – 20 Hz in the eye-safe spectral range of 1.5 – 1.6 mm. The two-module excitation of the active medium makes the distribution of the master laser radiation intensity in the output beam cross section more uniform and provides a reliable operation of the optical parametric oscillator.

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.

Titanium-sapphire laser pumped by the second-harmonic radiation of a neodymium laser with longitudinal diode pumping

A compact tunable source of laser radiation has been created on the basis of an Al2O3:Ti3+ crystal, with an energy per pulse of up to 85μJ, a pulse width of 5ns, and an M2 parameter of the order of 1.1, pumped with the second-harmonic radiation of a neodymium laser with longitudinal diode pumping. A KTP crystal with 58% conversion efficiency was used to convert the neodymium laser’s radiation to the second harmonic. The external differential quantum yield of the titanium-sapphire laser with respect to the second-harmonic radiation was 41%.

Parameters of the output beam of a longitudinally diode-pumped YVO{sub 4}/Nd:YVO{sub 4}-laser

The power and spatial characteristics of a longitudinally diode-pumped laser based on a composite YVO4/Nd:YVO4 crystal are studied. It is shown that the use of a composite crystal allows one to increase the external slope quantum efficiency from 36% to 41% and decrease the quality factor M2 of the output beam from 2 to 1.5 compared to these parameters for a Nd:YVO4 crystal.