| Abstrakt: |
Two methods are presented for generating sound at microwave frequencies with a Q-switched ruby laser. They are based on the modulation of the laser due to its mode structure and on the nonlinear properties of the solid. Sound is created at the laser modulation frequency. (1) Electrostrictive mixing in a LiNbO3 crystal, using a forward Brillouin scattering geometry, produces sound pulses at 800 MHz inside the crystal. Acoustic power densities were around 0.1 mW/mm2. (2) We then used surface heating of a metal film deposited on the surface of a dielectric crystal. At microwave frequencies, good efficiencies can be achieved; at 840 MHz, we generated in a gold film nearly 10 mW/mm2 of sound in 30-nsec pulses. [ABSTRACT FROM AUTHOR] |
