レーザマイクロフォンによる音波検出に関する研究

Abstract

Since the vibrating film is used for a current microphone, the detectable frequency is restricted.Recently, the influence on the human body by the sound wave of low frequency or high frequency from various apparatuses or equipmentshas became a problem. It is necessary to detect the sound wave of such frequency.A new type of microphone by using self-coupling effect of semiconductor laser has been studied.It is named the laser microphone.This microphone consists of laser and a light reflector, and it is not necessary to post-process a signal. An acoustic field is not disturbed by the microphone. The laser microphone can detect a sound withfrequency from 10Hz to 20kHz. The laser microphone is more sensitive than the condenser microphone in long distance from sound source, and is detectable a sound with lower frequency than condenser microphone. Moreover, if there is the sound source with some sound pressure, sound with the lower frequency below 10 Hz may be detectable.