| 摘要 |
PURPOSE:To modulate a second harmonic wave in response to the intensity of an information signal by providing a laser active medium for forming a resonator to a reflecting surface, and a harmonic wave generating medium provided in the resonator to generate a hermonic wave, and applying an ultrasonic wave to any of them. CONSTITUTION:In an acoustic-optical element, a transducer 7 is bonded to a dielectric crystal 6 such as TeO2 (tellurium dioxide), PbMoO4 (lead molybdate), and an AC voltage of MHz or more is applied thereto to generate an ultrasonic wave 9. A compressional wave by such an ultrasonic wave 9 or an electro- optical wave can be regarded as a diffraction grating generated in a crystal. If it exists in the crystal, an incident laser beam 10 is diffracted to bent its propagation path. Thus, the ultrasonic wave is bent in the propagating direction of an incident laser basic wave or a second harmonic wave to turn ON, OFF the ultrasonic wave or to alter the amplitude. Thus, the intensity of the basic wave or its second harmonic wave can be modulated. |
