Accession Number : ADP006750

Title :   Transport-Induced-Grating Interferometry;Application to Photorefractive Bi sub 12 Tio sub 20,

Corporate Author : UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES

Personal Author(s) : Xia, Ping ; Partanen, J. P. ; Hellwarth, R. W.

Report Date : 22 MAY 1992

Pagination or Media Count : 4

Abstract : We have developed a technique to measure interferometrically charge-transport-induced refractive index gratings in photoconductive insulators. All four parameters needed to describe fully the interaction between the two beams Bragg matched to the grating can be determined. We use the method to find that the complex optical polarizability of an occupied charge trap equals that of an unoccupied trap plus (0.7 - i4.5 + or - 0.7 + or - iO.4) x 10 to the -22nd cu.cm. in photorefractive Bi12TiO20. A spatially sinusoidal grating of optical intensity can produce a sinusoidal grating of occupied deep traps in photorefractive crystals. Under a wide variety of experimental conditions, a steady trap grating is produced, after sufficiently long times, that results in a change delta epsilon of the optical dielectric tensor of the form.

Descriptors :   *REFRACTIVE INDEX, *PHOTOCONDUCTORS, *OPTICAL INTERFEROMETERS, AMPLITUDE, CRYSTALS, DELTAS, DIELECTRICS, ELECTRIC FIELDS, FREQUENCY, INTENSITY, INTERACTIONS, PARAMETERS, TENSORS, TRANSPORT, TRAPS, GRATINGS(SPECTRA), ELECTROOPTICS, REFRACTION, SYMPOSIA.

Subject Categories : Optics
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE