| Summary: | 博士 === 國立成功大學 === 機械工程學系碩博士班 === 100 === A decoupled analytical technique based on the Mueller matrix method and the Stokes parameters is proposed for extracting nine effective parameters in linear birefringence (LB), linear dichroism (LD), circular birefrinegence (CB), and circular dichroism (CD), linear depolarization (L-Dep), and circular depolarization (C-Dep) properties of turbid media. In contrast to existing analytical models, the nine effective parameters are extracted in a totally decoupled manner. It is noted that the recent related studies did not show enough nine parameters of characteristics of bio-sample. The error and resolution analysis of the proposed approach is demonstrated by extracting the effective parameters of optical samples with varying degrees of linear / circular birefringence, linear / circular dichroism, and linear / circular depolarization given an assumption of errors ranging from ±0.005 in the values of the output Stokes parameters.
The results confirm the ability of the proposed method to yield full-range measurements of all the effective optical parameters. The validity of the proposed measurement method in testing different samples is proved. Also, the experimental results have showed that the CB property of two types polystyrene microspheres with containing D-glucose and de-ionized water with containing D-glucose is affected by the distance between the samples and detector. The decoupled nature of the analytical model yields several important advantages, including an improved accuracy and the ability to extract the parameters of optical samples with only linear birefringence, circular birefringence, linear dichroism, circular dichroism or depolarization property without using compensation technique or pretreatment. Moreover, by decoupling the extraction process, the “multiple solutions” problem inherent in previous models presented by the current group is avoided. As authors’ knowledge, this methodology could be the most comprehensive algorithm in extracting all nine effective parameters in decoupling in turbid media.
When using an optical fiber probe to measure the properties of anisotropic optical materials, some form of polarization controller is required to compensate for the inherent birefringence and diattenuation properties of the fiber. The experimental settings of the optical components within the polarization controller are generally determined on a trial-and-error basis; resulting in a lengthy experimentation process. Accordingly, in the present study, a method is proposed for calculating in advance the precise controller settings required to guarantee the formation of a free-space condition. In the proposed approach, the effective optical parameters of the optical fiber are determined using this analytical method, and the optimal settings of the polarization controller are then determined using a genetic algorithm. It is shown that the proposed approach enables a free-space condition to be achieved for the common polarization controller. The practical applicability of the proposed approach is demonstrated by remotely and absolutely measuring the linear birefringence and linear diattenuation properties of a quarter-wave plate and a polarizer, respectively.
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