級聯準相位匹配光學參量與倍頻效應之扇形週期性極化反轉鉭酸鋰寬頻藍光雷射晶片之研究

Broadband Blue Lasers Based on Cascaded Quasi-Phase-Matching OPO-SHG Processes Using Fan-out Periodically-Poled Lithium Tantalate

許翰棕(Han-Tsung Hsu)

指導教授 ： 彭隆瀚

國立臺灣大學/電機資訊學院/光電工程學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.01548

摘要

本篇論文分成三大部分：準相位匹配和光參振盪器原理的介紹、光參振盪和倍頻藍光雷射晶體之設計與研製，以及光參振盪器系統架設與藍光產生器腔內倍頻實驗分析。
理論部分，吾人先闡述非線性頻率轉換與準相位匹配理論，接著介紹光參振盪以及倍頻轉換理論。利用鉭酸鋰晶體在不同操作溫度下，設計滿足準相位匹配所需週期大小。接著採用本實驗室發展的鎳金屬內擴散配合高壓電致極化反轉製程技術，應用於厚度0.5mm之共熔鉭酸鋰晶片製作。實驗中設計光參-倍頻藍光雷射晶片，在倍頻部分做了單週期、三週期、變跡結構與扇形結構的設計，光參部份的週期為7.7576um，而倍頻部份：單週期為4.9865um；三週期為為4.9514um、4.9865um、5.0218um；變跡結構為4.9164um漸變到5.0749um，而扇形結構為並聯4.9024um至5.0606um，以此研製出長度為20mm的寬頻藍光雷射晶片。
光學量測部分，利用奈秒(~14ns) 1064nm紅外光雷射做為泵浦源，設計一共振腔可共振930nm將所研製完成之雷射晶片置入，測量此光參振盪器之出光轉換效率。本論文除了討論倍頻單週期、三週期與變跡結構的比較，還以752mW綠光搭配準相位匹配光參-級聯狀扇形結構倍頻藍光雷射晶片，以及雷射共焦腔之設計，實現頻寬1.9nm，斜線效率8.3%之465nm的寬頻藍光雷射，並得到26.8mW的藍光輸出，藍光轉換效率為3.56%。

關鍵字

非線性 ； 準相位匹配 ； 光參 ； 倍頻 ； 扇形 ； 鉭酸鋰 ； 藍光雷射

並列摘要

This thesis is composed of three parts：an introduction of the theory of quasi-phase-matching (QPM) and the principle of the optical parametric oscillator (OPO), the fabrication technique of one-dimensional periodically poled congruent grown lithium tantalite (LiTaO3) for cascade OPO-SHG 465nm blue laser and the measurement and analysis of OPO-SHG blue light generators.
First of all, the mechanism of nonlinear frequency conversion and QPM theory, and its application to the optical parametric oscillator and second harmonic generation (SHG) are introduced. By using Sellmeier equation, the QPM period of periodically poled LiTaO3 (PPLT) for the above application is designed. By taking advantage of the nickel-diffusion with high-voltage poling process, cascaded OPO-SHG devices on 0.5mm-thick congruent LiTaO3 substrate is fabricated. For cascaded OPO-SHG PPLT device, a multi-period SHG segment composed of single period, three periods , apodized and fan-out structure design for QPM-SHG is proposed. The period for OPO is 7.7576um, and the period for SHG is 4.9865um with single period；4.9514 um, 4.9865 um, and 5.0218 um with three periods；gradually changing from 4.9164um to 5.0749 um with an apodized structure design and gradualy changing from 4.9024 um to 5.0606 um with a parallel fan-out structure design. With this design, a 20mm-long chipwafer for generating OPO-SHG broadband blue light can be achieved.
Using a 1064nm infrared laser with 14ns pulse width as the pump source, a cascaded OPO-SHG chip in a concave laser cavity is shown to generate a 465nm broadband blue laser. Discussing the comparison of the optical measurement between single period, three periods, and apodized structure design for SHG, this work also includes the optical measurement of fan-out structure design . An average output power of 26.8 mW blue light laser has been achieved under a 752 mW input green power, which corresponds to a conversion efficiency of 3.56% . The spectrum is shown to have a 1.9 nm bandwidth and 8.3% slope efficiency.

並列關鍵字

nonlinear ； Quasi-Phase-Matching ； OPO ； SHG ； Fan-out ； Lithium Tantalate ； Blue Lasers

參考文獻

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