Narrow Results

In this paper, we present the results obtained with a thulium-doped (Tm-doped) photonic crystal fiber (PCF) amplifier operating in the sub-nanosecond regime with three different sources. In all cases, 40 μJ per pulse could be generated in an all-fiber approach with a good spectral and spatial mode quality. This source is developed for pumping a subsequent optical parameter generators/optical parameter oscillators (OPG/OPA) conversion system based on a gallium arsenide (GaAs) quasi-phase matched crystal.

Shortening the laser pulse length, ultimately toward the monocycle time scale, is one of the most important subject in the laser technology. Although this is also the case for free electron lasers (FELs), there is a fundamental and theoretical lower limit to the attainable pulse length in FELs, which comes from the so-called slippage effect intrinsic to the FEL amplification process. In this paper, a new FEL concept, which has been proposed to overcome the theoretical limit and realize monocycle FELs, is explained together with reviewing two schemes to implement the concept in the actual FEL system.