平面手征结构的旋光度精密测量

Study on precise measurement of the optical activity of plane chiral structure

基于精密步进电机和光纤光谱仪的光学测试系统,优化设计了一种精确测量手征结构样品旋光度的方案。对手征样品旋光性的理论分析结果表明,由于周期性手征结构样品制作过程中90°旋转对称性被打破,线偏振光经过样品后偏振面旋转角度与入射光的偏振面角度有关。实验测量结果直接证明了理论分析的正确性。利用设计的光学测试系统对采用电子束光刻技术制作的周期性平面手征结构样品进行旋光度测量的结果表明,样品在波长为633nm处具有0.05°的旋光度,很好证明了研制的周期性平面手征结构具有一定的旋光性。

An optimal design experimental method that can accurately measure the optical activity of the periodic planar chiral structure sample is proposed. This method is based on an optical test system mainly consisting a precise stepping motor and a fiber optical spectrometer. In addition, the optical activity of the periodic planar chiral structure is performed through detailed deduction of the formula and theoretical analysis. The analysis results reveal that when the linearly polarized light transmits through the periodic planar chiral structure the polarization azimuth rotation angle is a function of the polarization angle of the incident light, since the 90°-rotation symmetry is broken caused by the random errors of manufacture. Experimental results exactly demonstrate the validity of theory analysis. The optical activity of the periodic planar chiral structure sample fabricated by electron beam lithography technology is measured by the designed optical test system. The experimental results show that the periodic planar chiral sample possesses the optical activity of 0. 05° at the wavelength of 633 nm. As a consequence,the optical activity of the fabricated chiral structure is well demonstrated.