Smirnov A. Elastic deformation at relaxations photo thermo excitation at crystal with by different extenet of piezoelectrical chararacterristic.

Thesis deals with investigation of Rayleigh elastic waves excited in LiNbO3, GaAs and CdTe:Mn single crystals due to the absorption of light pulses available from Q-switched ruby laser (? = 694 nm, ?L = 20 ns) with prethreshold intensity. Transformation efficiency of optical energy to acoustical energy was determined to have a value of about (10-7-10-6). The direct registration of the acoustic response was made for LiNbO3 and GaAs piezocrystals. The generation of elastic waves in GaAs and CdTe crystals as result of the thermal expansion of the crystal lattice and thermalization of the photogenerated nonequilibrium carriers was analyzed. The displacement (? 5 nm) and the effective pressure (? 3 MPa) accompanying the elastic wave propagation were calculated at the location of 4 mm from the irradiated field. "Long-range" effect induced by laser irradiation in CdTe:Mn and Сd1-xMnxTe (х = 0.08-0.1) crystals was found and was connected with propagation of optically excited Rayleigh elastic waves. It was shown that the action of the acoustic wave excited in CdxHg1-xTe-based geterostructures by piezotransducer results in an essential change of the carrier concentration up to change of the conductivity type. The possibility of the inverse photothermal excitation of solid with activation of internal sources of the infrared radiation as a consequence of the acoustic wave energy absorption was determined.