準二維非線性光子晶體結構之雙波長紅光研究

Abstract

本論文共分成三部分介紹，第一部分主要介紹非線性光學與準相位匹配概念等理論；第二部分為週期性極化反轉結構的製作方法；最後為光學部分，考慮綠光雷射高斯模態在空腔時之有限發散角0.1°，透過準二維結構以設計非線性光子晶體之晶格動量G1,0與G1,0'其G1,0定義為與綠光雷射共線的動量，G1,0'定義為非共線的動量。而G1,0與G1,0'之間所形成的夾角，則根據於綠光雷射在空腔時的有限發散角0.1°，並以此角度前後各設計0.04°與0.2°以觀察趨勢，目的是使共振腔內的綠光雷射高斯發散動量能通過準二維結構，以產生兩種不同波長的可見光。 吾人發現在輸入能量為350mW下，共線G1,0的訊號強度是非共線G1,0'的0.35倍，強度相對弱很多，不過也發現隨著夾角從0.04°提升至0.2°後，能增強G1,0的訊號強度約2.6倍以上，其斜線效率能提升1.46%以上，出光閥值能降低39.7mW以上，且溫度頻寬也隨之增加約8℃，但尚未發現最佳值的結果。

This thesis is divided into three parts. The first part mainly introduces the theory of nonlinear optics and quasi-phase matching concepts. The second part discusses the fabrication methods of periodic polarization inversion structures. The final is the optical aspect, focusing on the design and implementation of two-dimensional nonlinear photonic crystals (NPCs) structures, which were superposed by two different one-dimensional periodically poled structures at a small. This simultaneous operation of two red light optical parametric oscillations (OPOs). The two reciprocal lattice vector G1,0, G1,0' of the separate 1-D NPCs are intersected at a small angle of 0.04°, 0.1°, 0.2° such that they can be quasi-phase-matched to the small divergent angle 0.1° of the pump green laser. The two-OPOs are operated with different efficiency, with the collinear one G1,0 which is relatively week red light intensity. We found that at an input energy of 350mW, the signal intensity of the collinear G1,0 is 0.35 times that of the non-collinear G1,0'. The intensity of G1,0 is significantly weaker. However, we also observed that as the angle increases from 0.04° to 0.2°, the signal intensity of G1,0 can be enhanced by more than 2.6 times. The slope efficiency can increase by more than 1.46%, the threshold power can be reduced by more than 39.7mW, and the temperature bandwidth can increase by approximately 8℃. However, the optimal value has not yet been discovered.