Tunable ultra-narrow linewidth diode laser for multiple metastable rare gas pumping.

We present what we believe to be a novel external cavity feedback structure based on a double-layer laser diode array with volume Bragg grating (VBG). Diode laser collimation and external cavity feedback result in a high-power and ultra-narrow linewidth diode laser pumping source with a central wavelength of 811.292 nm, spectral linewidth of 0.052 nm, and output power exceeding 100 W, with external cavity feedback and electro-optical conversion efficiencies exceeding 90% and 46%, respectively. The temperature of VBG is controlled to tune the central wavelength from 811.292 nm to 811.613 nm, covering the Kr* and Ar* absorption spectra. We believe this is the first report of an ultra-narrow linewidth diode laser that can pump two metastable rare gases.