[en] We have studied the effect of a relatively weak quantising magnetic field on emission spectra of a GaInAs/AlInAs quantum cascade laser near 10 K. The results demonstrate that, as the magnetic field induction increases to 7 T, the spectra broaden (to 5 meV) and split into three emission bands. As a result, we observe simultaneously up to 80 longitudinal lasing modes in the three bands and the integrated laser output intensity increases 70 times. The presence of bands in the emission spectra can be accounted for in terms of the magnetic quantisation of the laser levels into spinsplit Landau levels. The increase in emission intensity is attributable primarily to phonon resonance adjustment in a magnetic field. (lasers)

[en] A diode laser bar with unstable optically coupled resonators emitting 4 W of narrowband radiation is fabricated and studied. (lasers)

[en] The results of thermophysical investigations of semiconductor lasers are reported, which underlie the formulation of the optimal requirements on the materials, design parameters, and technological assembling conditions for high-power semiconductor lasers and their one- and two-dimensional arrays with the goal of most efficient heat removal. The methods are outlined for calculating the residual post-assembling mechanical stress and determining the assemblage conditions under which the attendant stress is insignificant and its effect on the laser quality is minimal. Also the methods are given for calculating the thermal resistance for different heat sinks, including heat sinks with forced cooling, and of determining the design requirements on the heat sink arising from specific service conditions. (lasers)

[en] Traditional (in the AlGaAs/GaAs system) and phosphorus-compensated (in the AlGaAs/AlGaPAs/GaAs system) laser heterostructures emitting at a wavelength of 850 nm are grown by MOVPE and studied. Laser diode bars are fabricated and their output characteristics are studied. The method used to grow heterolayers allowed us to control (minimise) mechanical stresses in the AlGaPAs/GaAs laser heterostructure, which made it possible to keep its curvature at the level of the initial curvature of the substrate. It is shown that the use of a compensated AlGaPAs/GaAs heterostructure improves the linear distribution of emitting elements in the near field of laser diode arrays and allows the power - current characteristic to retain its slope at high pump currents owing to a uniform contact of all emitting elements with the heat sink. The radius of curvature of the grown compensated heterostructures turns out to be smaller than that of traditional heterostructures.

[en] Repetitively pulsed generation (200 μs, 40 Hz) was obtained in a neodymium phosphate glass laser pumped by a 870-nm diode array. The maximum slope lasing efficiency with respect to the optical pump energy equal to 13% is restricted by the factor (∼0.23) of active-medium filling by the mode field. By adjusting the laser cavity, the single-transverse mode regime, in particular, the generation of the TEM₀₀ mode is obtained in the entire range of pump energies. (active media. lasers)

[en] The gain ∼3.5x10^-3 cm^-1 is obtained in the repetitively pulsed regime upon pumping a Nd-doped phosphate glass into the ⁴I_9/2-⁴F_3/2 absorption band by diode arrays at 874 nm. The pump efficiency for a sample of volume 6.7 cm³ exceeded 0.5 and was limited only by the geometrical factor and the excited-state lifetime of the Nd³⁺ ion. (lasers and amplifiers)

[en] The nonlinear-optical properties of heterogeneous liquid nanophase composites based on high-energy-gap Al₂O₃ nanoparticles are studied experimentally. The factors determining the nonlinear-optical properties of composites and their strong dependence on the matrix material are analysed and physical mechanisms are proposed to explain the results obtained. (nonlinear optical phenomena)

[en] Crystals of high-power laser diodes are directly mounted on copper heat-removing elements. The maximum output power of 25 W is obtained many times in a 808-nm cw laser with the 150-μm-wide strip contact at 20⁰C. After training tests at the output power of 6 W for 200 hours, the yield of acceptable samples was 80 %. No changes in the output parameters were observed after tests for 70 hours at the output power of 8.5 W. Tests are being continued. (lasers)

[en] An 8-μm quantum cascade laser is fabricated by the metalorganic vapour phase epitaxy method. A scheme of vertical transitions in a structure consisting of three quantum wells is used. The laser operates in a pulsed regime at temperatures up to 250 K. The threshold current density was about 3 kA cm^-2 and increased up to 6 kA cm^-2 at 250 K. The 1-μs pulse power in the multimode regime was 45 mW at 77 K.