Accession Number : ADP006782

Title :   Self-Pumped Phase Conjugation in Barium Titanate with High Intensity Nanosecond Pulses,

Corporate Author : IMPERIAL COLL OF SCIENCE AND TECHNOLOGY LONDON (UNITED KINGDOM) BLACKETT LAB

Personal Author(s) : Damzen, M. J. ; Barry, N.

Report Date : 22 MAY 1992

Pagination or Media Count : 4

Abstract : An investigation of self-pumped phase conjugation in barium titanate is made using nanosecond pulses (15 ns) derived from a repetitively pulsed (10 Hz) and frequency-doubled Nd:YAG laser system (532 nm wavelength). It is experimentally shown that high reflectivity (> 20 %) can be achieved. It is also shown that there is a progressive decrease in the reflectivity of both the corner-pumped and ring-passive geometries at pulse intensities of > 4 MW/sq.cm. At these intensity levels a high photo-carrier population is induced, altering the relative concentrations of Fe(2+) and Fe(3+) centres and leading to a strong intensity-dependent competition between hole and electron photoconductivity. For the corner-pumped geometry the intensity-dependence of the phase conjugate reflectivity is shown. The reflectivity increases with pulse intensity up to 20%. Small change in reflectivity occurs in the range 0.5 to 4 M/cm2 but a dramatic decrease in the reflectivity occurs at intensity > 4 MW/sq.cm.

Descriptors :   *BARIUM TITANATES, *PHOTOCONDUCTIVITY, *REFLECTIVITY, BARIUM, COMPETITION, ELECTRONS, FREQUENCY, INTENSITY, LASERS, PULSES, RINGS, YAG LASERS, OPTICAL PUMPING, IRON, ELECTRON TRANSPORT, PHOTOIONIZATION, REFRACTION, CRYSTALS, SYMPOSIA.

Subject Categories : Optics
      Nuclear Physics & Elementary Particle Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE