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Proceedings Paper

Photorefractive self-focusing and defocusing as an optical limiter
Author(s): Galen C. Duree Jr.; Gregory J. Salamo; Mordechai Segev; Amnon Yariv; Edward J. Sharp; Ratnakar R. Neurgaonkar
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Paper Abstract

Focusing and defocusing of laser light has been observed for many years. Kerr type materials exhibit this effect but only for high intensities. We show experimental evidence that photorefractive materials can also produce dramatic focusing and defocusing. Whereas Kerr materials produce this effect for high intensities, photorefractive materials produce these effects independent of intensity indicating that this effect would be ideal for an optical limiter. We compare the characteristics of Kerr and photorefractive materials, discuss the physical models for both materials and present experimental evidence for photorefractive defocusing. Self-focusing and defocusing was observed for any incident polarization although the effect was more pronounced using extraordinary polarized light. In addition, self-focusing or defocusing could be observed depending on the direction of the applied electric field. When the applied field was in the same direction as the crystal spontaneous polarization, focusing was observed. When the applied field was opposite the material spontaneous polarization, the incident laser light was dramatically defocused.

Paper Details

Date Published: 6 July 1994
PDF: 8 pages
Proc. SPIE 2229, Nonlinear Optical Materials for Switching and Limiting, (6 July 1994); doi: 10.1117/12.179585
Show Author Affiliations
Galen C. Duree Jr., Univ. of Arkansas (United States)
Gregory J. Salamo, Univ. of Arkansas (United States)
Mordechai Segev, California Institute of Technology (United States)
Amnon Yariv, California Institute of Technology (United States)
Edward J. Sharp, Army Research Lab. (United States)
Ratnakar R. Neurgaonkar, Rockwell International Science Ctr. (United States)

Published in SPIE Proceedings Vol. 2229:
Nonlinear Optical Materials for Switching and Limiting
M. J. Soileau, Editor(s)

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