Using homemade monochromator to produce the isolated 118.2 nm picosecond vacuum ultraviolet laser

• Main Authors: Wang, Cheng-Shiuan, 王政璿
• Other Authors: Tseng, Chien-Ming
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/87848952966851174837

碩士 === 國立交通大學 === 應用化學系碩博士班 === 103 === Since the beginning of the 1970s, with the development of nonlinear optics and laser system, light source for experiment can be expanded from long wavelength range to short wavelength band. Among them, vacuum ultraviolet light is a very good ionization source, and has already been used in many researches. For example, Vacuum-Ultraviolet-Ionization-detected-infrared predissociation spectroscopy (VUV-ID-IRPDS) of clusters can be used to understand intermolecular structures and interactions at the microscopic level, and the Resonance-enhanced Multiphoton Ionization (REMPI) technique with time-of-flight mass spectrometry (TOFMS) can be applied to the spectroscopy of atoms and small molecules. This technique is also widely used in the Velocity Map Imaging (VMI) for electron kinetic energy analysis in photoelectron photoion coincidence spectroscopy. In this thesis, we design a monochromator combined with a tripling cell to generate and isolate 118.2 nm vacuum ultraviolet light by tripling the third harmonic of a Nd:YAG laser (354.7 nm, repetition rate：1 kHz, pulse duration：~20 ps). Compare to those simple methods to get VUV light to do experiment, using the isolated VUV light has the benefits that the experimental result won’t be affected by the original pump light. Then, using the theoretical calculation that discussed by Nicholas P. Lockyer and John C. Vickerman et al to predict the optimized pressure of Xenon needed to generate the highest VUV light power. At last, using the detector we designed to detect 118.2 nm VUV light. The experimental result are not quite match what we expect, that is the generated VUV power is proportional to the cubic of pump power. We think that is because of Optical Kerr Effect, limiting the maximum energy of generated VUV light.