干涉式多光镊系统研究

为了定量测量光阱力,采用共面但不同轴的两束激光束产生干涉光场进而构成干涉式光镊系统的方法,分析了两束同向传输激光束以一定角度相干涉从而产生干涉条纹,即2维多光镊的原理,并给出了3维光镊的实验系统。采用分析作用在聚苯乙烯小球上的力的方法,进行了理论分析和实验验证,取得了光阱力分布的数据。结果表明,干涉式光镊可以提供皮牛级横向光阱力,能够实现光捕获,当只考虑光束的束腰半径和光功率两个因素时,实验数据与理论分析吻合得很好。这一结果对光镊技术在生物学、生物医学以及纳米技术等领域的应用是有帮助的。

Research of interferometric multiple optical tweezers

In order to measure the optical trap force, how two beams with optical off-axes in one plane generate an interference field was introduced, based on which a so-called interferometric optical tweezers was built up.Firstly how two coplanar laser beams at a certain angle interfered was analyzed,i.e.,the principle of two-dimension optical tweezers,then the principle of the three-dimension optical tweezers was presented.After analyzing the force acting on the polystyrene beads, the analytical and experimental data of the optical trap force were obtained.The result showed that interferometric optical tweezers could provide cross trap force about pico-Newton level and achieve optical trapping,the experiment data accorded with the theoretic results very well when only the optical power and the full width half maximum of the beam were considered.The result is very helpful to optical tweezers' application in biology, biomedicine and nano-technology.