電場蒙地卡羅模擬自動聚焦光束於組織中研究

Abstract

本論文旨在研究複雜光束於生物組織中的行進及其潛在的應用優勢，對此進行了數值模擬的探討。為了考慮光的波動特性，採用電場蒙特卡羅方法代替傳統蒙特卡羅方法。所採用的電場蒙特卡羅方法用於研究相干複雜光束於混濁介質中的作用。 對於入射光束的分布設定，採用拒絕採樣(Rejetion sampling)方法，從複雜光束的分布中隨機取樣入射光子的初始位置。模擬的組織模型由單層模型擴展到多層模型，其中對於遇到折射率不匹配的邊界時，光子經歷反射和透射的座標軸轉換公式於本篇中推導與實踐。程式逐步進行驗證，並將驗證結果與其他研究團隊產生的結果進行比對，程式模擬結果與文獻結果相當接近，說明程式有一定程度的可信度。 最後使用此程式進行貝索光束與艾里光束於混濁介質中行進的模擬，模擬結果與均勻光束和高斯光束的結果進行了比較。其強度隨穿透深度變化衰減曲線顯示了貝索光束衰減的較均勻光束與高斯光束緩慢。了解複雜光束在渾濁介質中行進的機制可能為潛在的雷射治療應用提供一些啟發。

In the thesis, the numerical investigation focuses on how complex beams propagate through biological tissue and the possible benefits they exhibit. The conventional Monte Carlo method is substituted with the electric field Monte Carlo method to address the wave characteristics of light. This new approach is utilized to explore how coherent complex light interacts with turbid media. To address the incident beam distribution, a sampling method is employed to determine photon positions from specific distributions. The tissue model is expanded from a single-layer to a multi-layer structure, with the derivation of formulas and the incorporation of reflection and transmission thoroughly presented. The program is validated step by step and its results are compared to those obtained by other research groups. The simulation results of the Bessel and Airy beams are evaluated in comparison to those of the uniform and Gaussian beams. The relationship between beam intensity decay and penetration depth is presented. Understanding the mechanisms of complex beam propagation in turbid media may offer valuable information for potential applications in laser therapy.