光折變晶體之雙波長全像記錄技術研究

Abstract

本論文研究光折變晶體光定影技術，經由照兩種不同波長的光，讓晶體內部的折射率有周期性的分布，並將光資訊長時間儲存在晶體中。以Kukhtarev方程式為基礎，使用單載子雙能階的數學模型，得到空間電場隨時間的變化，並且可以對整個記錄的過程做理論的模擬，並使用矽酸鉍(Bi12SiO20)及鈦酸鉍(Bi12TiO20)這兩種晶體的材料參數為模型，將材料參數對記錄結果的影響做討論。最終以實驗驗證模擬的結果並比較兩種不同晶體的特性。

In this thesis, we investigate the optical fixing in photorefractive crystals. There is a periodic distribution of refractive constant in crystals by using two different wavelengths recording, to keep the signals storage in the crystal for a long time. Base on Kukhtarev equation, we use a single-carrier band-transport model with two energy levels and obtain the changes of the space charge field with time. Therefor we are able to simulate the recording and fixing processes. We select two crystals, Bi12SiO20 and Bi12TiO20 and use their parameters for simulation respectively. Then we discuss how material parameters affect the recording and fixing processes. Finally we set up an experiment to stand for the simulation and compare the difference with these two crystals.