中国物理B ›› 2006, Vol. 15 ›› Issue (4): 729-734.doi: 10.1088/1009-1963/15/4/013

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Anomalous behaviour of long-time increase in diffraction efficiency of photorefractive grating in Ce:BaTiO3 in dark

张嘉文1, 徐英1, 洪治1, 张明2   

  1. (1)Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation,Zhejiang University,Hangzhou 310027,China; (2)Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation,Zhejiang University,Hangzhou 310027,China;Zhejiang Provincial Key Lab. of Optic Fiber Communication Technology,Zhejiang University of Technology,Hangzh
  • 收稿日期:2005-09-20 修回日期:2005-11-13 出版日期:2006-04-20 发布日期:2006-04-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 60078002).

Anomalous behaviour of long-time increase in diffraction efficiency of photorefractive grating in Ce:BaTiO3 in dark

Zhang Jia-Wen (张嘉文)a, Zhang Ming (张明)ab, Xu Ying (徐英)a, Hong Zhi (洪治)a   

  1. a Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027, China; b Zhejiang Provincial Key Lab. of Optic Fiber Communication Technology, Zhejiang University of Technology, Hangzhou 310032, China
  • Received:2005-09-20 Revised:2005-11-13 Online:2006-04-20 Published:2006-04-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 60078002).

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摘要： Anomalous long-time increase of the diffraction efficiency is observed in dark-decay experiments of photorefractive gratings in Ce:BaTiO2. It is deduced that a phase-conjugate beam is induced by the writing beam at acute angle to the +c axis of the crystal and it interferes with the other writing beam to form a second grating which is perpendicular to the first grating formed by the interference between two writing beams. The rising behaviour of the diffraction efficiency results from the different decay rates of these two photorefractive gratings. Furthermore, a simplified model of two gratings, both induced by two deep traps, is proposed to account for this phenomenon and the fitting results agree well with the experimental results.

关键词: dark decay, photorefractive grating, two deep-trap model, Ce:BaTiO$_{3}$

Abstract: Anomalous long-time increase of the diffraction efficiency is observed in dark-decay experiments of photorefractive gratings in Ce:BaTiO2. It is deduced that a phase-conjugate beam is induced by the writing beam at acute angle to the +c axis of the crystal and it interferes with the other writing beam to form a second grating which is perpendicular to the first grating formed by the interference between two writing beams. The rising behaviour of the diffraction efficiency results from the different decay rates of these two photorefractive gratings. Furthermore, a simplified model of two gratings, both induced by two deep traps, is proposed to account for this phenomenon and the fitting results agree well with the experimental results.

Key words: dark decay, photorefractive grating, two deep-trap model, Ce:BaTiO$_{3}$

中图分类号:  (Phase conjugation; photorefractive and Kerr effects)

  • 42.65.Hw
42.25.Hz (Interference) 42.70.Mp (Nonlinear optical crystals) 42.70.Nq (Other nonlinear optical materials; photorefractive and semiconductor materials) 42.79.Dj (Gratings)