High brightness diode pumped Er:YAG laser system at 2.94 µm with nearly 1kW peak power

We demonstrated a monolithic high-power diode-pumped Er:YAG laser at 2.94 μm with average output power of up to 50W and pulse energy beyond 300mJ in 400 μs pulses. The high peak power of nearly 1kW is delivered in a high quality beam (M² < 15), maintained over a large cooling water temperature range of 18-25 °C. The improved resonator configuration allows for stable operation from 0-10% duty-cycle in contrast to prior developments showing saturation. As a first application, fiber-coupling into a 230 μm, 0.2NA GeO₂-fiber with standard optics has been shown, reaching 30W average power and 200mJ pulse energy out of the fiber, only limited by the fiber..