Rainbow pattern analysis of a multilayered sphere for optical diagnostic of a heating droplet
Rainbow pattern analysis of a multilayered sphere for optical diagnostic of a heating droplet
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DOI：
10.1016/j.optcom.2019.02.061
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发表时间：
2019-06
影响因子：
2.4
通讯作者：
Jianxi Zhou;Yuan Fang;Jiajie Wang;Le Zhu;T. Wriedt
中科院分区：
文献类型：
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作者：
Jianxi Zhou;Yuan Fang;Jiajie Wang;Le Zhu;T. Wriedt
为了利用彩虹折射技术提取加热液滴内部的温度梯度分布，利用高斯光束照射多层球体的光散射模拟激光束照射下径向非均匀加热液滴的彩虹图案。本文在广义洛伦兹-米氏理论（GLMT）的框架内，采用一种基于理论重新表述和各种辅助函数计算的稳定数值算法来实现分析。分析了多层球的层数、高斯光束的束腰半径以及高斯光束中液滴的位置对彩虹图案的影响。通过对艾里模式的分析，可以确定用于模拟连续折射率剖面的最少层数。艾里图及其第一个最大值的角位置对液滴的折射率分布高度敏感。结果表明，当束腰半径小于液滴半径时，应考虑束腰半径的影响。而当高斯光束的束腰半径远大于液滴直径时，艾里模式中第一峰的角位置变化不大。
To extract the temperature gradient profile inside heating droplets using the Rainbow Refractometry technique, light scattering of a multilayered sphere illuminated by a Gaussian beam is applied to simulate the rainbow pattern of a radially inhomogeneous heating droplet in the case of a laser beam illumination. The analysis is implemented within the framework of Generalized Lorenz–Mie Theory (GLMT) by using a stable numerical algorithm developed recently based on theoretical reformulations and calculations of various auxiliary functions. Influences of the layer number of the multilayered sphere, beam waist radius of the Gaussian beam, and location of the droplet in the Gaussian beam on the rainbow pattern are analyzed. The least number of layers used to model a continuous profile of refractive index can be determined based on the analysis of Airy pattern. Both the Airy pattern and the angular position of its first maximum are high sensitive to the refractive index profile of the droplet. The results show that the influence of the beam waist radius should be taken into consideration if the beam waist radius of the beam is less than the radius of the droplet. While the angular position of the first peak in the Airy pattern changes little if the beam waist radius of the Gaussian beam is much larger than the diameter of the droplet.