旋转玻片法实现分时复用多光阱

Time-Sharing Multiple Optical Traps Using Rotating Glass Plate

利用倾斜放置于光镊光路中的旋转玻片对激光束进行斩波可以实现分时复用多光阱。详细讨论了光镊光路中引入玻片后,光阱位置的变化随玻片位置、厚度以及倾斜角度等因素的变化关系。设计了可以加载不同厚度玻片的8孔转盘,通过直流电机带动转盘旋转实现玻片对激光束的机械斩波,进而获得分时复用多光阱。利用分时复用多光阱实现了两个、三个不同大小聚苯乙烯小球的稳定捕获,通过改变玻片倾角可以改变光阱之间的距离,实现对捕获小球距离的控制。给出了分时复用多光阱的初步结果,从实验上证实了方法的可行性。

A novel method to realize time-sharing multiple optical traps is reported. Adding a tilted glass plate to the optical path, the laser propagation direction translates slightly. The dependence of trap position relying on the geometrical parameters of glass plate, such as plate site, thickness and tilted angle, are analyzed. A turnplate which is capable of loading as many as 8 glass plates of different thicknesses has been designed and fabricated. A direct current motor rotates the turnplate enabling mechanical chop of the laser beam, which forms the time-sharing multiple optical traps. Two and three polystyrene beads with different sizes are trapped by timing-sharing dual optical traps and tri-optical traps respectively. The distance between two adjacent traps varies when changing the tilted angle of the glass plate. Experimental results agree well with our theoretical ones discussed in the paper.