Fourier Transform Limited IR Source

我们建议购买傅里叶变换有限纳秒脉冲红外激光光源，以提高现有分子束表面散射装置的能力。脉冲放大的w-环染料激光器与注入种子Nd:YAG激光器的基础一起用于差频产生，其输出随后在光学参量过程中使用铌酸锂或硼酸钡进行放大。该光源在近红外2.0-0.8µm范围内提供了无与伦比的光谱亮度-窄带宽和高脉冲能量。使用这种激光器，小分子中的许多第一和第二泛音跃迁可以饱和，允许有效的人口转移到v=2或3。从这些高度非谐波振动状态，已经存在的设备基础设施将用于随后的近红外泛音激发，产生振动激发至少高达v=6的分子束。这样就实现了一种用于光束表面散射的光泵浦的新方法，即泵浦-泵浦激发。可行性计算表明，这种方法对氢化物（如HCl）和重原子双原子（如CO、NO）都是可行的。以这种方式产生的分子束将用于进行电子非绝热分子-表面相互作用性质的实验。

We propose to purchase a Fourier-Transform Limited nanosecond-pulsed infrared laser light source to enhance the capabilities of an existing molecular beam surface scattering apparatus. A pulse amplified cw-ring dye laser is used with the fundamental of an injection-seeded Nd:YAG laser for difference frequency generation, the output of which is subsequently amplified in an optical parametric process using Lithium Niobate or ß-Barium Borate. This light source provides unparalleled spectral brightness – narrow bandwidth and high pulse energy – in the near infrared from 2.0-0.8 µm. With this laser many 1st and 2nd overtone transitions in small molecules can be saturated, allowing efficient population transfer to v=2 or 3. From these highly anharmonic vibrational states, the already existing equipment infrastructure will be used for subsequent near IR overtone excitation, producing molecular beams with vibrational excitation at least up to v=6. In this way a new means of optical pumping for beam-surface scattering, namely PUMP-PUMP excitation, will be implemented. Feasibility calculations show that this approach is viable both for hydrides, e.g. HCl, as well as heavy atom diatomics, e.g. CO, NO. Molecular beams produced in this way will be used to carry out experiments on the nature of electronically nonadiabatic molecule-surface interactions.