摘要
提出用纳米光学透镜替代传统光镊装置中的大数值孔径几何光学透镜来捕获瑞利粒子的设想,基于电磁场时域有限差分方法计算了平面波经过纳米透镜后的衍射光场,并结合点偶极子近似计算了瑞利粒子在透镜衍射光场中的受力。研究结果表明,与传统光镊最好的情况(焦斑接近衍射极限)相比,本方案的捕获效率、稳定捕获区长度和光镊的品质因子都有很大程度的改善,尤其是出现在纳米透镜两侧的捕获区,对瑞利粒子的捕获效率和品质因子可提高2～3个量级,而且捕获粒子的受力具有强偏振相关性(不同于传统光镊),可用来实现粒子的旋转操作。
An idea that Rayleigh particles can be captured by replacing the geometry optical lens in the traditional optical tweezers with nano-lens is proposed. We calculate the diffraction field of a plane wave passed through the nano-lens by using the finite difference time domain （FDTD） method and the radiation force acted on the Rayleigh particles in the field based on the point dipole approximation method. The results show that, comparing to best results （focal spot close to the diffraction limit） of conventional optical tweezers, the trapping efficiency, stable trapping zone length and quality factor of the proposed tweezers can be greatly improved. Especially for the two capture zones on the both sides of nano-lens, the trapping efficiency and quality factor can be improved by 2 to 3 orders of magnitude, and also the force of trapped particles has a strong polarization dependence （unlike conventional optical tweezers）, which can be used to achieve rotation operation of particles.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2013年第9期325-334,共10页
Acta Optica Sinica
基金
中央高校基本科研业务费专项资金(2012-Ia-048)
关键词
衍射
光镊
激光捕获
纳米透镜
瑞利粒子
diffraction
optical tweezers laser trappings nano-lens Rayleigh particles
作者简介
刘子龙（1972-），男，博士，副教授，主要从事光与物质相互作用方面的研究。E-mail：liuyu-7212@163．com
