Running gratings in photoconductive materials

Abstract

Starting from the three-dimensional version of a standard photorefractive model (STPM), we obtain a reduced compact set of equations for an electric field based on the assumption of a quasi-steady-state fast recombination. The equations are suitable for evaluation of a current induced by running gratings at small-contrast approximation and also are applicable for the description of space-charge wave domains. We discuss spatial domain and subharmonic beam formation in bismuth silicon oxide (BSO) crystals in the framework of the smallcontrast approximation of STPM. The experimental results confirming holographic current existence in BSO crystal are reported.

Dynamic holographic interferometry in IR and visible range in semiconductor crystals for acoustical sensing (modeling and experimental realization)

“…Another type of phase modulation, describing running interference patterns (or "running gratings"), was considered theoretically using similar approach and compared with experiment in our paper [10] Theoretical modeling predicts that faster response (in order of nanoseconds) is possible in the same semiconductor crystals, using free carrier's gratings (Drude-Lorentz nonlinearity). We have described fast optical response, based on Drude-Lorentz nonlinearity (also called plasma nonlinearity) that play essential role in the surface-plasmon resonance phenomena.…”

Non-steady-state photoelectromotive force and two-wave mixing in photorefractive crystals under frequency modulated illumination

“…The electric current appears due to spatial shifts of the spacecharge and photoconductivity distributions in the crystal volume. The related techniques realized with an interference pattern running with constant velocity are called the holographic current [15] or moving photocarrier grating technique [16]. The two-wave mixing effect has been studied for years in photorefractive crystals and consists in intensity or phase redistribution for light waves propagating in the direction of the signal and reference beams [17][18][19][20][21].…”

Non-steady-state photo-EMF in semi-insulating GaAs under frequency-modulated illumination

“…The effect reveals itself as an alternating current arising in a semiconductor illuminated by an oscillating interference pattern [1][2][3]. The related techniques realized with an interference pattern running with constant velocity are called holographic current [4] or moving photocarrier grating technique [5]. The electric current appears due to spatial shifts of the space-charge and photoconductivity distributions in the crystal volume.…”