一般相位匹配条件下声光可调谐滤波器系统的理论分析

研究非共线性声光可调谐滤波器(AOTF)在一般相位匹配条件下的声光相互作用关系。对于通常设计制造的声光可调谐滤波器,它的o光和e光具有不同的波长,应用中无法同时使用此两束衍射光,为了使可用光强增大,应当使两束衍射光的波长相等。研究了使一般声光可调谐滤波器晶体两束衍射光波长相等的方法。对于未按照等值点理论制造的声光可调谐滤波器晶体,可以使入射光与晶体表面的法线成一个小的角度,根据一般相位匹配原理可以使两束光的出射波长相等。在实验中证明此方法的正确性,此角度称为等值偏置角。对于不同数值的衍射波长,有不同的等值偏置角,最后给出了等值偏置角随衍射波长的变化规律。

Theoretical Analysis to Acousto-Optic Tunable Filter System with Normal Phase Match Condition

The optic-acoustic reaction relationship is analyzed to noncollinear acousto-optic tunable filter(AOTF) under normal phase matching condition in this paper.To the generally designed AOTF,the diffracted o and e rays have different wavelengths.The two rays cannot be used simultaneously in practice.In order to magnify the intensity of light that can be used,the two diffracted rays should have same wavelength.The main research content of the paper is how to get two rays with same wavelength in normally produced AOTF crystal.For the AOTF crystal not produced by equivalent point theory,the incident light can be deflected a small degree with the normal of the crystal plane.By normal phase match condition it can be found that certain degree can diffracted the same wavelength rays.Experiments have validated the method.The deflected degree is called equivalent offset angle.For different diffracted wavelengths,there are corresponding different equivalent offset angles.Finally the variation rule of equivalent offset angle with diffracted wavelength is given.