使用三維時域擬譜法分析生物細胞的光學特性

Abstract

摘要 在本篇論文中，我們主要的研究目標是:「利用時域擬譜法 (pseudospectral time-domain method, PSTD法)，來模擬生物細胞的光學特性。」；而在我們研究中，只要能夠有效的提供出細胞的折射率分佈，任何的生物細胞我們都可以去模擬的，在這只是剛好用到HT-29細胞來做為研究。而我們主要是利用模擬的方法，將生物細胞的光學特性模擬出來。 模擬的方法主要是使用時域擬譜法，時域擬譜法是使用快速傅立葉轉換 (fast Fourier transform, 簡稱FFT)，來對Maxwell方程式的空間項做處理，而時間項的部分依然是使用中央差分法來計算。而光學特性方面，是以光學定理 (optical theorem) 為主，主要都是在觀測總散射截面 (total scattering cross section, TSCS) 和微分散射截面 (differential scattering cross section, DSCS) 之差異。 最後，我們希望藉由改變HT-29細胞內的折射率分佈，來觀測出總散射截面和微分散射截面值的變化，探討這些細胞內的折射率分佈，對於整體光學散射特性的影響。

Abstract In this thesis, our main topic of investigation is the “Pseudospectral Time-Domain Method (PSTD),”used to simulate the optical properties of biological cells. In our study, as long as we could effectively provide the distribution of cellular refraction index, we could also simulate any biological cell. But for the purposes of this study, we focus on the HT-29 cell as our model to simulate the optical properties of a biological cell. The simulation method we have adopted is the PSTD, which utilizes the Fast Fourier Transform (FFT) to treat the spatial dimension of the Maxwell’s equations. As for its temporal dimension, we have used the central difference method for its calculation. With regard to optical properties, we mainly used the optical theorem to measure the difference between the value of the Total Scattering Cross Section (TSCS) and that of the Differential Scattering Cross Section (DSCS). Finally, by changing the distribution of the refraction index inside the HT-29 cell, we measure the changes in both the TSCS and the DSCS, in order to understand its special effect on the overall scatter of optical light.