Tapered diode-pumped continuous-wave alexandrite laser

Abstract

We describe a low-cost and efficient alexandrite (Cr:BeAl2O4) laser that is pumped by a high-brightness tapered diode laser (TDL). The tapered diode (TD) provides up to 1.1 W of output power and its wavelength can be finetuned to either 680.4 nm (R1 line) or 678.5 nm (R2 line) for efficient in-line pumping. Continuous-wave (cw) output powers of 200 mW, slope efficiencies as high as 38%, and a cw tuning range extending from 724 to 816 nm have been achieved. To the best of our knowledge, the cw power levels and slope efficiencies are the highest demonstrated so far from such a minimal complexity and low-cost system based on the alexandrite gain medium. Consequently, TDs operating in the red spectral region have the potential to become the standard pump sources for cw alexandrite lasers in the near future.