光致旋转中晶体微粒厚度对旋转频率的影响

摘要

In the paper,the basic process of the interaction between the laser beam and the birefringent crystal particle is discussed theoretically,and physical model of optical rotation due to the transfer of spin angular momentum from the laser beam to particle is established.For improving rotation frequency of crystal particle,the relation between rotation frequency and thickness of CaCO3 和SiO2 crystal particle was analyzed in theoretical research and experimental re-search.The sine relation curve between CaCO3 and SiO2 particle’s rotation frequency and thickness was simulated with MATLAB software,and the results show that experimental curve of rotation frequency and thickness is the period-ic sine undulation,meanwhile rotation frequency is proportional to laser power.Rotation frequency is measured under the same laser power,the results show the maximum frequency of CaCO3 particles is 1.7 Hz,and the maximum fre-quency of SiO2 particles is 1.5 Hz when laser power is 1 0 mW.The conclusion can be used to the thickness choice of the rotor and the optimization control of rotation frequency in actual application.%从理论上讨论了双折射晶体微粒与圆偏振光束作用的基本过程，建立了由于光束自旋角动量向双折射晶体微粒的转移所引起的旋转现象的物理模型。为提高晶体微粒的旋转频率，从理论和实验两方面对CaCO3和SiO2晶体微粒的厚度与其旋转频率的关系进行了详细分析。基于MATLAB软件分别模拟出双折射晶体微粒的厚度与其旋转频率的正弦关系曲线，并通过实验测得相应的晶体旋转频率数据进行验证。结果表明，在有效激光功率为10 mW的条件下 CaCO3和 SiO2双折射晶体微粒的最大旋转频率分别为1.7 Hz 和1.5 Hz。该结果可用于光致旋转在微机械设计中转子厚度的选择和其旋转频率的最优化控制。