Innovative Laser Sources Operating Around 2 µm

We report on a variety of continuous wave and pulsed laser sources based on Thulium- and Holmium-doped materials, emitting in the spectral range around 2 µm. This includes continuous wave Thulium-doped fiber lasers which have been realized based on the beam combining technique by using tapered fused bundles and truly single mode WDM cascades, respectively. A pulsed laser source emitting nano- or picosecond pulses has been developed in a master oscillator power amplifier (MOPA) configuration, which consists of a gain-switched diode operating at a wavelength of 1.95 µm, followed by Thulium-doped fiber-based pre- and main amplifiers. Furthermore, we present a femtosecond regenerative amplifier system using Thulium:YAP and Holmium:YAG crystals with emission wavelengths around 1.95 µm and 2.1 µm, respectively. Output energies of more than 700 µJ have been generated with both systems.