High-power diode laser pumps for alkali lasers (DPALs)

Abstract

We present performance data of recent high-power laser diodes emitting at typical pump wavelengths for alkali vapor lasers: 852 nm for cesium, 780 nm for rubidium, 766 nm for potassium, and 670 nm for lithium atoms. Due to different approaches in alkali laser systems, we report on usual pumps at these non-standard wavelengths with typical line widths of a few nm used for collisional and pressure broadened gas absorption lines as well as on wavelength stabilized laser diodes using volume Bragg gratings (VBGs) for systems with narrow gas absorption lines. The detailed characterization of laser diodes available at DILAS includes power, efficiency, spectral data, and life time results. While bars at 6xx and 7xx nm are limited in optical output power due to the strong in-built strain, especially the bars at 852 nm with a small inbuilt strain have the biggest potential in terms of pump power. The power conversion efficiency in cw operation is as high as 60% at 100 W. Higher power and operation at increased heat sink temperatures up to 50°C are possible depending on lifetime requirements.