Sum-frequency generation of deep UV light in BBO crystals

• Main Authors: Huang, Jui-Yue, 黃瑞裕
• Other Authors: Tang Chen-Yau
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/74949966262006821278

碩士 === 淡江大學 === 物理學系 === 85 === The major purpose of this thesis is to investigate the principle and effects of second-order nonlinear optical frequency conversion, compare between different types of phase matching methods, and produce tunable coherent deep ultraviolet( UV) light by sum-frequency generation (SFG). In the theoretical part, the effects of frequency mixing of optical waves in nonlinear media are reviewed, and some basics of uniaxial and biaxial crystals and of β-barium borate(BBO) crystals are discussed. According to thn-縱lready known optical characteristics of BBO, the phase matching angles for parametric conversion and SFG in BBO are calculated; the walk off of the sum-fr?簇ncy beam in BBO is also discussed. In the experimental part, we used the third harmonic(TH) of a nanosecond pulsed Nd:YAG laser to pump a BBO based optical parametric oscillator (OPO) which provides a wavelength tuning range from 450 nm to 690 nm for the signal wave and from 730 nm to about 1.7 mm for idler wave. We used the signal wave (478-650 nm) and the residual pump beam of the OPO as the input beams to perform SFG in BBO crystals, and thus, tunable coherent deep UV output from 203.6 nm to 229.5 nm can be obtained. The average SFG conversion efficiency is about 15% and the average energy of deep UV output is about 8mJ/pulse. We also find that the SFG conversion efficiency depends mainly on the intensity, beam divergence, beam quality, and the degree of phase matching of the interacting beams. The study shows that the SFG of the OPO output and the TH beam of the Nd:YAG laser can be very efficient for producing tunable deep UV light. The SFG system is all- solid-state and is easy to operate.