同時產生雙波長近紅外光學參量振盪器及橘黃光雷射研究

Abstract

本論文主要分三部分:(1)非線性晶體與準相位匹配基礎理論，(2)週期性極化反轉鉭酸鋰(PPLT)設計與製作，(3)利用腔鏡進行腔內光學參量振盪器與和頻產生橘黃光雷射之光學量測，並利用成像系統觀察腔內模態之情形。 第一部分探討非線性光學理論、準相位匹配以及光學參量振盪器基礎理論。 第二部分利用鎳擴散製程與高電壓極化反轉技術製作週期性極化反轉鉭酸鋰晶體。以並聯光參產生結構串連和頻週期結構方式，使532nm泵浦綠光雷射，在達成準相位匹配條件後，以光參轉換成兩對分別為信號光 980nm/972nm與閒置光波長 1175nm/1163nm近紅外光，再以和頻對閒置光轉換成波長的584nm之橘黃光雷射。 第三部分為光學量測部分，利用理論計算出溫度頻寬並與實驗結果對比，測量光學轉換效率。吾人使用光學成像系統，以觀察泵浦光入射於晶體上不同位置週期所造成之效率產生效應；並觀察對應不同晶體位置之腔內紅外與黃光腔內模態形成過程中場型變化。

This thesis is composed of three parts: (1) quasi- phase matching theory on nonlinear crystal, (2) design and fabrication of periodically poled lithium tantalate crystal (3) optical measurement of intra-cavity optical parametric generation and sum frequency generation(SFG) and use of a home design imaging system to observe the laser mode patterns of NIR and yellow-orange inside the cavity. In the first part, we investigate the theory of quasi-phase matching for optical parametric oscillation (OPO) and, sum frequency generation (SFG). In the second part, we use the high-voltage poling technique to fabricate periodically poled lithium tantalates (PPLT). The PPLTs were designed to have parallel OPO structures cascaded by a segment of the SFG structure. The devices can convert a 532 nm pump laser into dual-wavelength 1175/1163 nm idler waves in two parallel of the OPOs which are oscillating simultaneously. In addition, it can perform SFG to convert the NIR idler waves of 1175/1163 nm wavelength into an orange-yellow 584nm laser. The third part is about optical measurement. We analyze the theoretical value of temperature bandwidth and made a comparison with the experimented data, and the variation in the slope efficiency at different pump positions. Furthermore, we use a home design imaging system to investigate the mode patterns of the NIR OPOs and the SFG laser as the beams propagate along the PPLTs crystal inside the cavity.