準相位匹配之級聯光學參量振盪器 與倍頻橘黃光雷射研究

Abstract

本篇論文內容是由三大部分構成:(1) 準相位匹配基本理論與光學參量振盪器原理之介紹，(2 )光學參量振盪器-倍頻橘黃光晶片之設計與研製，(3) 用光學方法測量光參振盪器-倍頻橘黃光晶片，並觀測共振腔內橘黃光模態的情況。 理論的部分介紹非線性頻率轉換、準相位匹配與光參振盪器。接著在鉭酸鋰光學參量振盪器晶體週期設計的部分中，以並聯光學參量振盪結構級聯倍頻與和頻週期結構方式，波長為532nm之綠光泵浦雷射達成準相位匹配之條件，使532nm綠光泵浦源先光學參量轉換成兩對波長為1163nm/1186nm之閒置光與986nm/964nm之信號光等近紅外光後再倍頻與和頻換成波長為581nm/587nm/593nm的橘黃光雷射。最後再利用本實驗室研究的晶片內擴散鎳金屬配合極高電壓致極化反轉之製程，用於製作厚度為1mm之共熔鉭酸鋰晶片。 光學量測部分，以脈衝之泵浦光經過光參振盪器晶體，以及級聯光參振盪器之腔內倍頻與和頻架構，成功的產生出效率為8.1%，而共振閾值為30.1MW/cm2的多波長橘黃光雷射，其光束品質因子Mx2與My2分別為2.23及5.13。

There are three parts in this thesis: (1) Quasi-phase matching (QPM) theory and the theory of optical parametric oscillators (OPO), (2) the design and fabrication of optical parametric oscillator-second harmonic generation (OPO-SHG) orange-yellow light QPM crystals, (3) optical measurement of OPO-SHG orange-yellow light generation and observation of the intra-cavity laser mode patterns of orange-yellow. First of all, we outline the QPM theory for OPO and SHG processes. Secondly, the design of periodically poled congruent LiTaO3(PPCLT) which has parallel OPO structures cascaded by SHG and sum frequency generation(SFG) structures is introduced. This design can convert a 532 nm green laser pump into idler/signal waves at 1163/986 nm and 1186/964 nm simultaneously near infrared. In addition, it can continuously convert the idler waves 1163/1186 nm to SHG of 581/593 nm also enable SHG of 587 nm orange-yellow lasers. By taking the nickel-diffusion assisted electric poling process, cascaded OPO-SHG devices on a 1mm-thick CLT substrate is fabricated. Finally, the OPO-SHG device was measured to exhibit multi-wavelength spectra with a slope efficiency of 8.1% and threshold intensity of 30.1 MW/cm2, the orange-yellow laser was also characterized with a beam quality factor Mx2=2.23 and My2=5.13.