| Summary: | 碩士 === 國立海洋大學 === 電機工程學系 === 88 === The nonlinear optical effects , in addition to using phase-matching method and materials which possess large nonlinear optical coefficients , applying electric field upon materials to modulate its nonlinear optical coefficient is an effective and easy way to increase the SHG intensity .
(9.5/65/35) ceramic has nowadays been used for electrooptic devices due to its interesting ferroelectric properties , high transparency and its well-performed electroooptic effects even in the form of non-single crystal . Although also it has an averaged central -symmetric structure in zero applied electric field and is isotropic , when a dc electric field is applied to the material , the structure transforms to tragonal , which is noncentral-symmetric . It's nonlinerity depending on how large the applied electric field is.
We utilized the method of corona poling to provide a large field at the tip of an electrode so that large electric field in PLZT can be created and enhanced SHG intensity was observed. We studied the observed Maker fringes and calculated the change in nonlinear optical susceptibility. From our experimental results, we found that nonlinear optical susceptibility in PLZT can be enhanced by applying an dc electric field or by corona poling under various environmental. The results will be discussed.
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