Abstract

Infrared free electron laser is a unique broadband tuning IR light source and useful tool to trace the reaction and vibrational energy transfer dynamics. It is essential for the infrared free electron laser debug and optimization to accurately characterize the wavelength and micropulse profile of the infrared free electron laser output. By synchronizing the infrared free electron laser and tabletop femtosecond laser with high precision, infrared free electron laser-sum frequency generation setup, a sum frequency generation spectroscopy setup using infrared free electron laser pulses, is developed. Through sum frequency generation cross-correlation, the infrared free electron laser output wavelength and micropulse duration are measured from the delaytime-dependent infrared free electron laser-sum frequency generation spectra of a ZnS window. The infrared free electron laser-sum frequency generation measured infrared free electron laser wavelength is linearly correlated with the theoretically calculation with the fixed electron beam energy and variable undulator magnetic gaps. And the measured micropulse duration is 2.0 ps@5.25 µm and 2.9 ps@8.35 µm. These results demonstrate the excellent ability of sum frequency generation in the diagnostic and characterization of infrared free electron laser output profile, and the quality of the infrared free electron laser pulse structure.

摘要

红外自由电子激光器是一种独特的宽带调谐红外光源，是追踪反应和振动能量转移动力学的有用工具。准确表征红外自由电子激光输出的波长和微脉冲轮廓对于红外自由电子激光器的调试和优化至关重要。通过高精度同步红外自由电子激光器和台式飞秒激光器，研制了红外自由电子激光和频产生装置，即利用红外自由电子激光脉冲产生和频光谱装置。通过和频生成互相关，从 ZnS 窗口的延迟时间相关红外自由电子激光和频生成光谱测量红外自由电子激光器输出波长和微脉冲持续时间。红外自由电子激光和频产生测得的红外自由电子激光波长与理论计算线性相关，电子束能量固定，波荡器磁隙可变。测得的微脉冲持续时间为 2.0 ps@5.25 µm 和 2.9 ps@8.35 µm。这些结果证明了和频生成在红外自由电子激光输出轮廓的诊断和表征以及红外自由电子激光脉冲结构的质量方面的卓越能力。