産研 THz-FEL における EO 計測の周波数解析

We are conducting the electro-optic (EO) sampling measurements using a Ti:sapphire laser synchronizing to the accelerator in order to understand the time structure of the terahertz free electron laser (THz-FEL) at the Institute of Scientific and Industrial Research, Osaka University. Up to now, the EO signal varies in shot-to-shot, but there is a periodic variation in a macropulse. To make clear the physical reason of this phenomena, we are studying the frequency analyses for the EO signals in various conditions of the FEL operation. We report the present situation of this study