High-Power Actively-Pulse-Shaped 2 mJ Nanosecond-Pulsed Tm3+-Doped Photonic Crystal Fiber Amplifier Emitting At 2048 nm

Pulsed high-brightness laser sources at wavelengths around 2 μm are important for applications in medicine, material processing, defense, and nonlinear frequency conversion to the mid-infrared. Thulium-doped fiber lasers (TDFLs) offer a compact and robust solution to address this spectral range efficiently. However, it is challenging to simultaneously achieve high pulse energies, high pulse peak powers and high average output powers, with narrow linewidth emission at wavelengths longer than 2 μm - where atmospheric transmission is high and nonlinear crystals like ZnGeP2 exhibit low background absorption.