钽铌酸钾晶体的电控双折射效应

Electronically Controlled Birefringence of Potassium Tantalate Niobate Crystals

钽铌酸钾(KTN)晶体作为一种性能优良的多功能晶体,具有显著的二次电光效应。在应用该晶体进行电光调制实验的过程中,发现了一种基于该晶体的电控双折射效应。为了对这种电控光束偏转分离现象做出合理的解释,运用KTN晶体的二次电光效应原理和菲涅耳方程建立了光束分离偏转的数学模型,从理论上阐明了该现象产生的原因,给出了非寻常光的偏转角度与电压及光束入射角之间的函数关系。并进一步通过实验测量了KTN晶体的电控双折射现象,对相应理论进行了实验验证。实验结果表明在532nm激光斜入射的情况下,KTN晶体具有明显的电控双折射效应和较大的非寻常光偏转角。

As an outstanding quality multi-functional crystal,potassium tantalate niobate（KTN）crystal is notable for its quadratic electro-optical effect.An electronically controlled birefringence effect based on the crystal is found during the experiment of electro-optical modulation.To illustrate this kind of performance that one electronically controlled beam is separated into two beams of orthogonal polarization light,the principle of quadratic electro-optical effect and the Fresnel equation are used to construct the mathematic model of beam separation deflection.The reason for the phenomenon is elucidated theoretically,and the function relationship between voltage,incident angle and deflection angle of extraordinary light is given.In the experiments,the electronically controlled birefringence phenomenon of KTN crystal is further measured and the corresponding theory is verified.The experimental results show that KTN crystal has obvious electronically controlled birefringence effect and large deflection angle of extraordinary in the case of 532 nm laser oblique incident.