光偏振的微小旋转角的测量技术

A Measurement Technique of the Tiny Rotatory Angle of Polarization

本实验提供一种对光偏振的微小旋转角的测量技术．实验采用法拉第调制方法，分别用632．8nm的He-Ne激光器和532nm的LD泵浦固体激光器做测量光源，对乙醇水溶液（浓度50％）的磁光法拉第偏振角进行测量．当改变外加磁场的磁感应强度时，可使偏转角在亚毫度范围内取值．采用这一技术，对蔗糖水溶液的旋光角进行测量，浓度低达每毫升10－4克．为具有小的费尔德常数的化学物质或生命物质的旋光测量提供了很好的手段．

This experiment demonstrates a measurement technique of very small rotatory angle of polarization. Faraday rotatory angle is measured in ethanol solution of concentration 50% usiflg 632.8 nm He-Ne laser and 532 nm LD pump solid laser as measuring sourcest respectively. The rotatory ang1e can take values in the mag-nitude of sub-millidegree (10-4degrees ) as the intensity of induction field changes.Applying this polarimetric technique, the rotatory angle can be measured in the cane sugar solution of concentration of 10-4g/ml. Therefore it provides a good polarimetric method for chemical and life substances with small Verdet constants.