CAJ | 학술논문

针对高精度微小旋光度测量需求,本文提出一种基于弹光调制器的高分辨率微小旋光度测量方法及实验验证方案.该方法原理是当起偏器、检偏器相对弹光调制器分别45°和0°放置时,待测微小旋光度与弹光调制信号的二次谐波近似成线性关系.为验证该方法的实验效果,本文采用双光电管的平衡探测方法设计了一个低噪声前置光电转电路,并利用锁相放大技术从弹光调制信号中提取谐波分量,在上述基础上实现了高分辨率旋光度测量.实验结果表明,基于弹光调制器的新型旋光度测量方法可实现高达10-6rad的高分辨率旋光度测量;并且本文设计的双光电管平衡探测电路可明显提高信号的信噪比,而基于锁相放大技术提取弹光调制信号谐波分量的方案也有助于实现高分辨率旋光度检测.
침대고정도미소선광도측량수구,본문제출일충기우탄광조제기적고분변솔미소선광도측량방법급실험험증방안.해방법원리시당기편기、검편기상대탄광조제기분별45°화0°방치시,대측미소선광도여탄광조제신호적이차해파근사성선성관계.위험증해방법적실험효과,본문채용쌍광전관적평형탐측방법설계료일개저조성전치광전전전로,병이용쇄상방대기술종탄광조제신호중제취해파분량,재상술기출상실현료고분변솔선광도측량.실험결과표명,기우탄광조제기적신형선광도측량방법가실현고체10-6rad적고분변솔선광도측량;병차본문설계적쌍광전관평형탐측전로가명현제고신호적신조비,이기우쇄상방대기술제취탄광조제신호해파분량적방안야유조우실현고분변솔선광도검측.
For satisfying the demand of high precision small optical rotation measurement, an new method is proposed and experimental researched, which is using the photoelastic modulator(PEM). Its measurement mechanism is that when the polarizer is set at 45° to PEM and analyzer is set at 0° to PEM, the magnitude of the optical rotation is linearly dependent with the PEM's second harmonic. For verifying the effect of this mechanism, a low noise photoelectric conversion circuit is designed that using dual photodiode, and the second harmonic is detected by a lock-in amplifier. Finally, a high resolution rotation measurement is experimentally realized. Our experimental results show that the a high precision small optical rotation measurement that reaching up to 10-6 rad based on the PEM is possible. Besides, the dual photodiode-based photoelectric conversion circuit design could improve the signal-to-noise ratio. And the lock-in amplifier circuit used for processing the harmonic signal of PEM also contributes to high resolution small optical rotation measurement.