中国物理B ›› 2004, Vol. 13 ›› Issue (9): 1464-1467.doi: 10.1088/1009-1963/13/9/018

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Light-induced scattering in SBN:Cr crystal under external electric fields and its suppression

赵建林, 李振伟, 杨德兴, 马仰华   

  1. Department of Applied Physics, Northwestern Polytechnical University, Xi'an 710072, China
  • 收稿日期:2003-08-28 修回日期:2003-11-27 出版日期:2004-06-21 发布日期:2005-06-21
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 60077018).

Light-induced scattering in SBN:Cr crystal under external electric fields and its suppression

Zhao Jian-Lin (赵建林), Li Zhen-Wei (李振伟), Yang De-Xing (杨德兴), Ma Yang-Hua (马仰华)   

  1. Department of Applied Physics, Northwestern Polytechnical University, Xi'an 710072, China
  • Received:2003-08-28 Revised:2003-11-27 Online:2004-06-21 Published:2005-06-21
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 60077018).

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摘要： In this paper, the enhancement of light-induced scattering in congruent SBN:Cr (Sr_{0.61}Ba_{0.39}Nb_2O_6:Cr) crystals in the presence of an externally applied electric field and its suppression are studied. If a coherent image is focalized in SBN:Cr crystal without applying external electric field, the output image will remain clear, because of the weak photorefractive effect in the crystal. When a field is applied properly along the crystal axis, markedly enhanced scattering from the signal beam and the output image dispersion can be observed due to the increase of the photorefractive two-beam coupling gain and the light-induced index change in SBN:Cr crystals. By introducing a coherent or incoherent beam with higher intensity the light-induced scattering can be suppressed through the erasure of scattering gratings. The difference between coherent and incoherent beam is that the former can also amplify the signal beam as the scattered light is removed, whereas the latter can only make the signal beam revert to its initial state. The results obtained under different experimental conditions are consistent with theoretical analysis.

关键词: light-induced scattering, SBN:Cr crystal, external electric field, photorefractive two-beam coupling

Abstract: In this paper, the enhancement of light-induced scattering in congruent SBN:Cr (Sr$_{0.61}$Ba$_{0.39}$Nb$_2$O$_6$:Cr) crystals in the presence of an externally applied electric field and its suppression are studied. If a coherent image is focalized in SBN:Cr crystal without applying external electric field, the output image will remain clear, because of the weak photorefractive effect in the crystal. When a field is applied properly along the crystal axis, markedly enhanced scattering from the signal beam and the output image dispersion can be observed due to the increase of the photorefractive two-beam coupling gain and the light-induced index change in SBN:Cr crystals. By introducing a coherent or incoherent beam with higher intensity the light-induced scattering can be suppressed through the erasure of scattering gratings. The difference between coherent and incoherent beam is that the former can also amplify the signal beam as the scattered light is removed, whereas the latter can only make the signal beam revert to its initial state. The results obtained under different experimental conditions are consistent with theoretical analysis.

Key words: light-induced scattering, SBN:Cr crystal, external electric field, photorefractive two-beam coupling

中图分类号:  (Diffraction and scattering)

  • 42.25.Fx
42.65.Hw (Phase conjugation; photorefractive and Kerr effects) 42.70.Mp (Nonlinear optical crystals) 42.70.Nq (Other nonlinear optical materials; photorefractive and semiconductor materials)