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0. L. ARTEMENKO (a) and B. B. SEVRUK (b)The phenomenon of parametric excitation of a transverse hypersonic wave by laser and microwave radiation in cubic semiconductor crystals with strain-dependent dielectric constant and piezoelectric effect induced by a constant transverse electric field is investigated. The numerical analysis of the exact dispersion equation is performed providing resonance dispersion relations of the acoustic wave gain hctor for a wide range of electromagnetic wave frequencies and semiconductor plasma parameters. The boundaries of the absolute instability region and electromagnetic field threshold value are set up, as well as the optimal relationship between the collision frequency and the frequencies of electromagnetic and plasma waves governing acoustic wave generation and amplification.Der Effekt der parametrischen Verstarkung von Querhyperschallwellen durch Laser-und Mikrowellenstrahlung in kubischen Halbleiterkristallen mit dehnungsabhangiger Dielektrizitatskonstante und durch ein konstantes transversales elektrisches Feld induziertem Piezoeffekt wird untersucht. Durch die numerische Losung einer exakten prazisen Dispersionsgleichung werden die Resonanzdispersionsabhangigkeiten des Verstarkungsfaktors einer akustischen Welle in einem brei ten Frequenzbereich der elektromagnetischer Wellen und einem weiten Bereich der Parameter des Halbleiterplasmas errechnet. Es werden die Grenzbereiche absoluter Instabilitat, der Schwellenwert des Feldes elektromagnetischer Wellen angegeben, und fur die Verstarkung und Erzeugung akustischer Wellen wird eine optimale Beziehung zwischen der Kollisionsfrequenz und der Frequenzen elektromagnetischer und Plasmawellen gefunden.

The process of interaction between circularly polarized coherent transverse phonons and slow electrokinetic waves in the centrosymmetric crystal placed in a longitulinal magnetic field and possessing strong strain dependence of the dielectric constant caused by the electrostriction is considered. The cut-off system of equations for the process of nonlinear four-wave interaction in crystal with a quadratic electrostriction corresponding to direct energy conversion from helicon to acoustic wave is derived. Tle solution is sought for numerically in the vicinity of a synnchonism point determined by the intersection of Helicon and phonon dispersion curves at different values of semiconductor plasma parameters. The results show the possibility of effective phonon parametric amplification in semiconductor crystal with the electroinduced elastic anisotropy.

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