The IR-FEL facility at RRCAT: Commissioning experiments and first saturation of lasing at [formula omitted] wavelength

Abstract

An Infrared Free Electron Laser (IR-FEL) has been designed and developed at RRCAT for potential use in the IR/THz spectroscopy of materials in low temperature and high magnetic field environment. The first commissioning experiments on the IR-FEL setup were performed in 2016, but the out-coupled power achieved in these experiments was two to three orders of magnitude lower than the saturated out-coupled power predicted by the FEL design simulations, mainly due to certain limitations in its injector system. The setup has recently undergone a major upgrade with the installation and commissioning of a new injector system, and lasing at a wavelength of 28μm has recently been observed in the setup. This is the first saturation of lasing of an FEL in India, with a measured Continuous Wave (CW) out-coupled IR power of 5 - 7.3 mW. This paper discusses the present status of the IR-FEL project at RRCAT, and the results from recent commissioning experiments leading to lasing in the setup.