Measurement of Small Lateral Vibrations of Speckle Patterns Using a Non-steady-state Photo-EMF in GaAs: Cr

Abstract

We report the observation of a non-steady-state photo-EMF generated in a semi-insulating GaAs: Cr crystal by vibrating speckle patterns. The experimentally observed basic dependences of the output signal on the vibration frequency and amplitude as well as on the light intensity are in reasonable agreement with those observed earlier for vibrating sinusoidal light patterns. Using this novel technique, lateral vibrations of diffusely scattering objects can be easily detected over a wide range of frequencies and amplitudes.