Far-infrared cavity dump coupling of the UC Santa Barbara free-electron laser

Abstract

A Nd:YAG laser-induced semiconductor switch for far-infrared (FIR) radiation was mounted inside a free-electron laser (FEL) wiggler cavity to act as an intracavity output coupler. By timing the FEL to the Q-switched laser, the FIR switch could be turned on during the intracavity laser saturation period. In addition to demonstrating the generation of short, high peak power pulses, the cavity dump coupler (CDC) was used for the first time to image the intracavity mode structure of a FEL and to perform steady-state saturation spectroscopy studies in the FIR.