摘 要

微纳光纤是直径范围达到微米或纳米量级的一类光纤，微纳光纤具有低传输损耗和大百分比倏逝场等特性，微纳光纤的传输损耗相比与同样在微纳尺度的硅基平面波导低的多，但又比常规的单模光纤略高，并且虽然微纳光纤的直径很小，但它的机械强度却比普通光纤高得多，比普通光纤拥有更广泛的应用范围。已经在光纤传感检测、光电子器件、光纤通信、近场光学、非线性光学等研究领域都有广泛的应用。

本文首先研究了熔融拉锥法制备的微纳光纤的传输特性，分析了微纳光纤的光纤为纤芯空气为包层的结构，进一步分析了其单模条件，并基于其单模条件分析了微纳光纤基本模式分布下的倏逝场分布特性，用matlab数学软件仿真了微纳光纤纤芯内外部的倏逝场分布情况和距离光纤不同位置的倏逝场强度；之后分析了基于倏逝场的微纳光纤光镊的应用原理，分析了倏逝场中微粒受到的作用力的产生原因，选定了计算分析方法；最后基于适用于直径远小于光波长的瑞利粒子的电磁模型，模拟计算微纳光纤作为光镊对瑞利粒子的捕获力。

研究得出微纳光纤直径越小纤芯外倏逝场强度越高的结论，仿真结果符合理论，并证明了距离微纳光纤越远处倏逝场的强度越小，模拟计算微纳光纤倏逝场对瑞利粒子的作用力，改变部分影响因素时，计算得出的微粒受力变化情况符合实际情况，根据得出的结论可以在进行实际捕获瑞利粒子时调整微粒距离光纤的距离、光纤直径等因素来提升微纳光纤光镊的捕获能力，对光镊的实际应用有一定指导意义。

关键词：微纳光纤；倏逝场；光镊；瑞利粒子

Abstract

Micro-nano fiber refers to a light guide fiber with a diameter in the order of micrometers or nanometers. Micro-nano fiber has strong light field confinement capability and a large proportion of evanescent field characteristics. The transmission loss of micro-nano fiber is compared with silicon-based micro-nano scale planar waveguide Much lower, but higher than conventional single-mode fiber, and although the diameter of micro-nano fiber is small, but its mechanical strength is much higher than ordinary fiber, has a wider range of applications than ordinary fiber. It has been widely used in optical fiber sensing and detection, optoelectronic devices, optical fiber communication, near-field optics, nonlinear optics and other research fields.

This paper studies the melting cone method of micro-nano optical fiber transmission characteristics, analyzed the single-mode condition of micro-nano optical fiber, and then based on the condition of single mode analysis evanescent field features, matlab simulation of micro-nano optical fiber core, internal and external evanescent field distribution and the distance of different location of the optical fiber evanescent field strength, and based on the strong micro-nano fiber evanescent field, the application principle of micro nano fiber optical tweezers was analyzed. Finally, the trapping force of Rayleigh particles as optical tweezers was simulated.

The study concludes that the smaller the micro-nano fiber diameter is, the higher the evanescent field strength of the core is. The simulation results are in line with the theory, and it is proved that the intensity of the evanescent field is further away from the micro-nano fiber. The simulation calculation of the micro-nano fiber evanescent When the force of the field on Rayleigh particles changes some of the influencing factors, the calculated force changes of the particles are in line with the actual situation. According to the conclusion, the distance between the particle and the fiber and the diameter of the fiber can be adjusted to improve the capturing

ability of the micro-nano fiber optical tweezers.This has certain guiding significance to the practical application of optical tweezers.

Key Words：Micro-nano fiber; Evanescent field; Optical tweezers; Rayleigh particle

目 录

摘 要 I

Abstract II

第一章 绪论 1

1.1 研究背景和意义 1

1.2 微纳光纤国内外研究现状 1

1.3 微纳光纤的特性和应用 3

1.4 本论文的主要工作 3

第二章 微纳光纤传输特性研究 5

2.1微纳光纤的单模条件 5

2.2 微纳光纤的倏逝场 6

2.3 微纳光纤倏逝场分布理论 6

2.4 微纳光纤倏逝场分布的模拟 9

2.5 本章小结 10

第三章 微纳光纤倏逝场捕获瑞利粒子 12

3.1 微纳光纤光镊原理 12

3.1.1梯度力和散射力 12

3.1.2瑞利粒子的计算模型 12

3.2 微纳光纤倏逝场捕获瑞利粒子的模拟 12

3.3 本章小结 16

第四章 论文工作总结及展望 18

4.1工作总结 18

4.2 展望 19

参考文献 20

致 谢 21

第一章 绪论

1.1 研究背景和意义

随着科学技术的发展，人们对与各种事物的研究越来越深入细致，因此器件的微型化发展已经成为如今科研工作的的重要方向，直径在微纳尺度的光纤作为微型光学器件中最基本的信息传输单元，对它的研究是整个光学研究领域中最实用的内容，现在光纤器件的直径尺度己经达到了微米和纳米级别，这种直径在微米和纳米级别的光纤即为微纳光纤，在小尺寸光子学等众多的研究领域，微纳光纤的研究已经受到了广泛关注。