[3] [3] Ewbank M D,Vazquez R A,Neurgaonkar R R, et al. Contradirectional two-beam coupling in absorptive photorefractive materials application to Rh-doped strontium barium niobate(SBN:60). J. Opt. Soc. B, 1995, 12(1):87～98

[4] [4] Vazquez R A,Ewbank M D,Neurgaonkar R R. Photorefractive properties of doped strontium-barium niobate. Opt Comm., 1991, 80(3,4): 253～258

[5] [5] Woike T,Photorefractive properties of Cr-doped Sr0.61Ba0.39Nb2O6 related to crystal purity and doping concentration. App. Phys.(B), 2001, 72:661～666

[6] [6] Zhao J,Wang B,Wu J, et al. Investigation of photorefractive two-wave coupling in Cr-doped strontium barium niobate (SBN:Cr) crystal. Chinese Physics, 2001, 10(8): 739～742

[8] [8] Tomita Y,Suzuki A.Photorefractive proerties of Cr-doped strontium-barium niobate at 514.5nm and 623.8 nm : A comparative study. Appl Phys (A), 1994, 59: 579～582

[9] [9] Koichi Sayano, Amnon Yariv, Ratnakar R. Neurgaonkar. Photorefractive gain and response time of Cr-doped strontium barium niobat. Appl Phys Lett,1989, 55(4): 328～330