Spectrally Narrowed Pump Diode Arrays for Diode Pumped Alkali Lasers

Diode Pumped Alkali Vapor Lasers (DPAL) are a promising technology for high power directed energy lasers because of several favorable characteristics, notably the small quantum defect which results in very little deposition of waste heat in the lasing medium and potentially good conversion efficiency and beam quality. Existing diode pumps have spectra that are too wide and inaccurately controlled, so external stabilization schemes using external volume gratings is required, but the spectral narrowing and tuning range provided is too limited and cost is too high. Building on a successful Phase I demonstration, we will develop high power internally stabilized pump diode bars for alkali pumping with sub-GHz linewidths and tuning rates of 80 pm/degree and which provide scalability to multi-kW stacks.