Abstract

The subject of space charge waves covers a wide range of physics from plasmas, acoustics and semiconductors to the relatively new area of photorefractive optics. Space charge waves can be regarded as quasiparticles in solids and are of great interest not only in the case of photorefractive materials but also in the case of many semiconductors. They determine the dynamic behavior of the space charge distribution in the crystal and can be excited optically by various methods. A powerful technique is to use the spatially oscillating interference pattern created by two coherent laser beams. Then, if the frequency of oscillation and the grating spacing of the interference pattern coincide with the frequency and the wavelength of the corresponding space charge wave, a resonance excitation of the space charge wave occurs. Space charge and photoconductivity waves play important role in inducing non-steady-state photocurrents in photorefractive crystals [1]. This effect provide an unique opportunity for direct measurement of the photoelectron's drift mobility from the position of the second resonance maximum in frequency transfer function of the photocurrent

© 2001 EPS