改良式Kurtz粉末二倍頻測試法研究結晶鈦酸鍶鋇粉末之線性與非線性光學特性

Abstract

本論文主旨在於改良Kurtz粉末二倍頻測試法量測粉末材料的折射率和有效倍頻係數，以提供新材料在粉末製備階段之線性與非線性光學特性的參數評估方法。利用液態波導量測散射倍頻光強度分佈與粉末平均顆粒大小的關係，擬合我們的經驗公式求得材料的有效倍頻係數和基頻光與倍頻光之色散，並且可以判斷該材料是否可達相位匹配。利用結晶粉末如KDP、BBO、Urea、LiNbO3和石英晶體（quartz）作為標準測試樣品，與該晶體塊材之實際值作比較，得到折射量測誤差小於5%；有效倍頻系數和色散量測誤差小於10%。以此改良式量測系統研究新材料Ba1-xSrxTiO3(BST)四元化合物之線性與非線性光學特性，得到Ba0.8Sr0.2TiO3折射率為1.87及有效倍頻係數為BBO的4.77倍，為具有可相位匹配之良好的非線性光學材料。

The objective of this thesis is to provide a modified Kurtz method for measuring the indices of refraction and the effective second harmonic generation coefficients of powder materials. We used a liquid waveguide to measure the relation of the intensity of the scattered second harmonic generation and the qverage particle sizes, The experimental results were fitted by our empirical formula to estimate the effective second harmonic generation coefficient, the dispersion of fundamental and second harmonic waves, as well as to determine whether the material is a phase matchable one. We used the crystalline powder materials KDP, BBO, Urea, LiNbO3 and crystalline quartz as the standard samples. By comparing with the generally recognized values of corresponding properties of the bulk crystals, the error from the measurement of the index of refraction is less than 5% and those of the effective second harmonic gescration coefficient and dispersion are less than 10% The linear and nonlinear optical properties of new quaternary materials (Ba, Sr) TiO3 (BST) were studied by our modified method The experimental results showed that the index of refraction of Ba0.8Sr0.2TiO3 is 1.87, the effective second harmonic generation coefficient is 4.77 times of the BBO's, and it is a phase matchable material with good nonlinear optical properties.