Intra-cavity Second Harmonic Green Laser based on Periodically Poled Lithium Niobate

• Main Authors: Shun-Han Yang, 楊順涵
• Other Authors: 彭隆瀚
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/07069510648237348074

碩士 === 臺灣大學 === 光電工程學研究所 === 95 === This thesis is organized into three parts: (a) an introduction to the theory of Quasi-Phase Matching (QPM) theory, (b) the design and fabrication of Periodically Poled Congruent-grown Lithium Niobate (PPCLN, LiNbO3) and Lithium Tentalate (PPCLT, LiTaO3), and (c) the implementation of intra-cavity QPM green laser. Three fabrication methods of PPLN/PPLT were investigated in this work. They include (a) an improved photo-resist poled method, (b) poling with surface domain inversion, and (c) poling with self-assembled micro-sphere lithographic patterns. Results of periodical poling through 500 m-thick CLN/CLT with a periodicity of 6.67 m/7.7 m were achieved by methods (a) and (b)；whereas high aspect ratio of poled domains can be achieved in the method (c). A single-pass second-harmonic generation (SHG) characterization of a 6 mm-long 1D-PPCLN by a Nd:YAG 1064 nm/26 ns pulsed laser exhibits a conversion efficiency of 30% at a pump intensity of 26.5 MW/cm2. For implementation of an intra-cavity SHG green laser, we achieve a continuous wave operation of QPM-SHG green PPCLN laser that emits 60 mW power at a 1W pump power from a 808 nm diode laser. This figure is about twice that of a conventional intra-cavity SHG green KTP laser tested under the same cavity structure.