【摘要】 在非同时读出条件下测量了 Ce:KNSNB晶体两波耦合体光栅衍射效率随写入光强比、写入光偏振态和写入光夹角的变化关系 ,并与同时读出条件下衍射效率变化规律的测量结果进行了比较 ,发现二者基本一致 .利用耦合波理论对实验结果进行了理论分析和拟合 ,拟合结果和实验数据较好的吻合更多还原

【Abstract】 At non simultaneous writing reading process,the diffraction efficiency of the volume grating written by two wave coupling in a Ce∶KNSBN photorefractive crystal is experimentally studied with respect to the writing beam intensity ratio,the polarization of writing beams and the angle between the writing beams.Due to the energy transfer,the diffraction efficiency strongly depends on the polarization of the writing beams.While the writing beams are both with extraordinary polarization or both with ordinary polarization,the volume grating has different maximum diffraction efficiency value and the maximum diffraction efficiency appear at different writing beam intensity ratio β.The grating written by the ordinarily polarized beams obtains its maximum diffraction efficiency at β=0.6.But the volume grating written by the extraordinarily polarized beams obtains its maximum diffraction efficiency at β=0.12,which has a "left shift".While the writing beams are both with extraordinary polarization or both with ordinary polarization,the maximum diffraction efficiency is corresponding to the same angle between the writing beams.But the maximum diffraction efficiency of extraordinary writing beams case is about three times of that of ordinary writing beams case.The experimental result is also compared with that obtained at simultaneous writing reading process and they agree with each other.Finally the coupling wave theory was induced to fit the experimental data and the fitting curves are coincident with the experimental data very well.更多还原