Compact, Ultra- Narrow-Bandwidth, High-Power Diode Laser Pumps for Diode-Pumped Alkali Lasers

The diode pumped alkali laser (DPAL) allows for a potentially scalable approach towards a MW-class high energy laser system. By using an alkali vapor gain medium, one overcomes the intrinsic thermo-optical limitations of more conventional diode-pumped solid state laser (DPSSL) media. High spectral brightness diode pump sources are proposed as the enabling element for efficient, kW-class DPAL systems. We propose to develop a compact, ultra-narrow-bandwidth (<1 GHz), high power diode laser pumps for DPALs. The ultra-narrow pump diode lasers will be designed in Phase I to provide kW-class power levels with spectral linewidths in the range of 500 MHz. In Phase I, a proof-of-principle demonstration will be performed. In Phase II, a kW-class narrow linewidth DPAL pump laser will be constructed. This combination of power, spectral linewidth, and compactness is not available in any other pump laser today. In addition, our approach is traceable to a very compact pump size and weight, which is a key driver for DoD applications.