I B Mukhin

Faraday Rotators With Short Magneto-Optical Elements for 50-kW Laser Power

Faraday rotators with short magneto-optical elements are created and experimentally studied. The magneto-optical elements are made three to four times shorter either by cooling them to nitrogen temperatures or by increasing the magnetic field. These ways are shown to increase maximum average laser power passing through the Faraday isolators up to 50 kW

Influence of the orientation of a crystal on thermal polarization effects in high-power solid-state lasers

The polarization thermal self-action of laser radiation propagating in an isotropic crystal has been studied experimentally. New nonlinear effects have been observed for the first time. These effects include a change in the symmetry of the depolarized-field distribution and the qualitative dependence of the degree of the self-induced depolarization on the geometry of the beam and crystal. The classical problem of self-induced depolarization has been analytically solved in the general form for an arbitrary orientation of any cubic crystal. The theoretical results agree well with the experimental data. The optimum orientation of the laser crystal has been determined, which can be effectively used in lasers with high average power.

Experimental study of thermally induced depolarization in Nd:YAG ceramics

Spatial modulation of a laser beam with a transverse size of the order of one grain size is experimentally found at thermal depolarization in Nd:YAG ceramics. This effect, which was theoretically predicted earlier, is typical for ceramics only, with no analogs either in glasses or in single crystals.

Thermal Effects in End-Pumped Yb:YAG Thin-Disk and Yb:YAG/YAG Composite Active Element

The small signal gain and phase and polarization distortions of laser radiation have been investigated theoretically and experimentally in end-pumped Yb:YAG thin-disk and Yb:YAG/YAG composite active element under nonlasing conditions. Comparison of experimental data with calculation results reveals an additional heat release whose negative influence is three times stronger than that of amplified spontaneous emission in the thin-disk active element.

Drastic reduction of heat release in magneto-optical elements: new ways towards a 100 kW average power Faraday isolator

Faraday isolators with low heat release are created for high average power lasers. The heat release is reduced either by shortening the optical element (due to cooling to nitrogen temperatures or use of superconducting solenoids) or by employing non-traditional magneto-optical media with better thermo-optical properties. It is shown that the suggested ways make it possible to create a Faraday isolator for 100kW average power.

Improvement of thermal management in the composite Yb:YAG/YAG thin-disk laser

To improve the thermal management in the composite Yb:YAG/YAG thin-disk laser a new design of laser head is developed. Thermal-induced phase distortions, small signal gain and lasing in the upgraded laser head are investigated and compared with previously published results. A substantial decrease of the thermal lens optical power and phase aberrations and increase of the laser slope efficiency are observed. A continuous-wave laser with 440 W average power and 44% slope efficiency is constructed.

Yb : YAG thin-rod laser amplifier with a high pulse energy for a fibre oscillator

High (more than ten times) small-signal gain is demonstrated in an Yb : YAG single crystal thin rods with pumping by a fibre-coupled diode laser. A four-pass amplifier for a fibre master oscillator with an average output power exceeding 15 W at a pulse repetition rate of 3 MHz is fabricated based on this active element. The small-signal gain in the developed amplifier is 26 dB, which is comparable with the gain in regenerative amplifiers. The possibility of obtaining sub-millijoule pulse energy at a pulse repetition rate of tens of kilohertz is shown.

Comparative characteristics of Yb:(YLa)2O3laser ceramics

Two samples of laser ceramics synthesised at Russian institutes by two different methods are studied. The optical quality of the samples is measured, and efficient (36.6%) lasing in one of the samples is obtained under pumping at a wavelength of 940 nm.

Comparison of composite and disk shaped active elements for pulsed lasers

Characteristics of active elements with different geometry have been compared theoretically. The possibility to reduce thermally the induced distortions of laser radiation and to increase the stored energy in a disk laser with a composite active element at room and cryogenic temperatures has been investigated

Sub-joule level high repetition rate cryogenic disk laser

Spectral and thermooptical properties, the stored energy and amplification in Yb: YAG disks are investigated at 77-300K temperature range. The current status of the laser system development with 0.5J output energy at 1kHz repetition rate is presented.