摘要
本文针对纳米材料的纳米操作,提出了一种复合激光近场光镊与AFM探针进行纳米操作的方法,并基于动量守恒原理,采用三维时域有限差分方法建立了该方案中激光近场对纳米微粒的作用力模型,分析了各轴向光阱力的分布情况,讨论了两探针间距离、针尖材料的电导率、入射平面光场的偏振方向、入射角和波长等参数对近场光阱力的影响。结果表明:位于耦合光场中特定位置的微粒可被捕获至固定位置,所需的捕获功率大大低于传统光镊所需的捕获功率;为实现稳定的纳米操作,光纤探针与AFM探针的距离应保持在孔径范围内,两探针的相互位置应保持成垂直关系,同时应选用短波长的捕获激光,并保持激光偏振方向与AFM探针轴线的匹配。本文设计的近场光镊与AFM探针相复合的纳米操作系统,能大大扩宽近场光镊和AFM系统在纳米操作上的应用范围。
Recently, interest in nano-manipulation using the evanescent wave generated by near-field optical probes has been growing. The possibility of using the metallic tip of an atomic force microscope illuminated by evanescent wave from a fiber probe to create optical tweezers for selective manipulation of nano-particles is explored. A generalization of the conservation law for momentum using three-dimensional finite difference time domain method for rigorous calculations is applied to analyze near-field trapping forces. Calculations show that the scheme is able to trap smaller particle with lower laser intensity than that required by conventional near-field optical tweezers. The trapping potential is sensitively dependent on the distance between two probes and incident angle, as well as the incident polarization direction and wavelength. Based on the high manipulation efficiency and the high resolution of AFM system, the scheme allowing for effective and accurate manipulation ofnano-particles opens a way for research on single nano-particle area：
出处
《光电工程》
CAS
CSCD
北大核心
2011年第2期1-8,共8页
Opto-Electronic Engineering
基金
国家自然科学基金(90923041)
浙江工业大学特种装备制造与先进加工技术教育部重点实验室开放基金资助项目(2009EP012)
关键词
三维时域有限差分法
光阱力
近场光镊
AFM探针
three-dimensional finite difference time domain
trapping force
near-field optical tweezers
AFM probe
