DPAL: historical perspective and summary of achievements

Abstract

Alkali vapor lasers are under extensive research and development during the past decade because of their potential for scaling to high powers while maintaining a good beam quality. Also, a possibility of using efficient diode lasers for pumping alkali vapor promises high total wall plug efficiency for a Diode Pumped Alkali Laser (DPAL). Since the first DPAL demonstration with output power of 130 mW in 2005 1 , a significant progress in this field was achieved. The output power of about 1 kW in continuous wave (CW) operation with optical efficiency close to 50% was recently demonstrated for a Cs DPAL 2 . Also, the DPALs based on other alkali metals (Rubidium and Potassium) were demonstrated 3,4 . In spite of these significant achievements, there are still several problems in DPAL power scaling exist that must be addressed. Among them are the thermal 5 and photoionization 6 issues that become important even at power level about several tens of watts. In this paper we present a historical review of the alkali laser research and development, discuss the most important achievements and future perspectives in this field of research.