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Proceedings Paper

Energy transfer characteristics of photorefractive wave mixing in BaTiO3 at three wavelengths
Author(s): Mohammad Hossien Majles Ara; M. Shaban; J. Badraghi; A. Banaei
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Paper Abstract

Photorefractive two-wave mixing and energy transfer in BaTiO3 are studied at three wavelengths using He-Cd, He-Ne and diode laser. The Photorefractive signal beam gain is measured as a function of the pump beam intensity, beam ratio intensity, spatial frequency of the grating, and angle between the grating vector and c axis of the crystal. The exponential gain coefficient is calculated from signal beam gain, and its dependence on the same parameters is studied. The dependence of the signal beam gain and exponential gain coefficient on spatial frequency are also evaluated theoretically and found to be in good agreement with the experimental data. Also, the signal beam gain is studied as a function of wavelength, and a very high value is obtained at 441.6nm. Diffraction efficiency of photorefractive gratings recorded in two-beam coupling configuration in crystal of BaTiO3 at multiple wavelengths is reported. We study the distortive effects in a thick PR hologram due to the angle between the two interfering beams and present our results on effect of spatial frequency on the diffraction efficiency. The behavior of crystal is compared at 441.6 nm, 632.8 nm and 780 nm using He-Cd, He-Ne and semiconductor diode lasers respectively. Value of diffraction efficiency of the crystal is higher at 441.6 nm as compared to other wavelengths. Figure-of-merit parameters such as the maximum change in the refractive index, the space charge field at saturation, the trap density of the charge carriers, and the photorefractive sensitivity of the crystals are calculated from the experimental data. Since the absorption in BaTiO3 varies strongly with wavelength, its influence has been included in the calculation of the figure-of-merit parameters.

Paper Details

Date Published: 14 February 2005
PDF: 8 pages
Proc. SPIE 5776, Eighth International Symposium on Laser Metrology, (14 February 2005); doi: 10.1117/12.611692
Show Author Affiliations
Mohammad Hossien Majles Ara, Teacher Training Univ. (Iran)
M. Shaban, Teacher Training Univ. (Iran)
J. Badraghi, Research Institute of Applied Sciences (Iran)
A. Banaei, Research Institute of Applied Sciences (Iran)

Published in SPIE Proceedings Vol. 5776:
Eighth International Symposium on Laser Metrology
R. Rodriguez-Vera; F. Mendoza-Santoyo, Editor(s)

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