二維藍綠與紫外光非線性晶體雷射之研究

Two-Dimensional Blue, Green and UV Nonlinear Crystal Laser in Lithium Niobate

徐兆慶(Chao-Ching Hsu)

《光學工程》 85期 (2004/03) Pp. 71-75

https://doi.org/10.30011/OE.200403.0008

摘要

本論文的內容主要為利用非線性晶體及準相位匹配達成倍頻轉換原理的討論，一維及二維周期性極化反轉鈍酸鋰晶體的製作，以及晶體的溫度調變、角度調變，幫浦光源波長調變對倍頻輸出之影響等光學量測的實做。
在晶體的製作方面，嚐試並比較了一些製作方式，並成功地製作出周期6.8μm之一維周期性極化反轉鈮酸鋰晶體，及20×20μm之二維周期性極化反轉鈮酸鋰晶體，且能達到6 mm的有效長度，以及在區域內整齊且良好的周期圓形。
光學量測方面，由溫度調變、角度調變、波長調變，成功地驗證了理論的預期。在波長調變實驗中，可達到約33%外部轉換效率，以及估計約50%的內部轉換效率。並且由實驗中發現二倍頻紅外、三倍頻藍綠光及四倍頻紫外光同時產生。

關鍵字

鈮酸鋰 ； 準相位匹配 ； 倍頻轉換

並列摘要

This thesis is organized in to three parts: (1) the theory of second harmonic generation (SHG) by using two-dimensional nonlinear photonic crystal and quasi-phase-matching method, and (2) the fabrication of 1D and 2D periodically poled lithium niobate, and (3) the optical measurements, including temperature-resolved, angle-resolved, and wavelength-resolved SHG experiments.
Several fabrication methods are compared. 1D PPLN with 6.8 μm period and 20 PPLN with 20×20 μm period were successfully made. In particular, 6 mm efficient length for the 20 PPLN was achieved, and the domain patterns are regular and fine over the whole range under O-ring.
In the measurements, the results of temperature, angle, and wavelength tuning experiments agree well with theoretical prediction. In the wavelength-tuning experiment, 33% external efficiency and about 50% internal efficiency are achieved. Infrared ray laser (second harmonic), blue and green laser (third harmonic) and ultraviolet laser (fourth harmonic) are generated and observed simultaneously.

並列關鍵字

lithium niobate ； quasi phase match ； harmonic generation