Less heat - more power

We demonstrate a diode laser pumped semiconductor disk laser (SDL) at 2 µm wavelength of increased efficiency. By employing a novel pumping concept at a wavelength of 1470 nm, we optimize the power conversion efficiency of the 2 µm SDL. This is exemplarily shown for an SDL with an output power of over 20 W in continuous wave operation. This sets a new benchmark regarding efficiency and output power for these SDLs.