Comparison of the relative merits of surface-emitting versus edge-emitting solid-state laser pumps

Surface-emitting arrays (SEAs) have the potential to significantly reduce the cost and improve the performance of diode array-pumped solid-state lasers. The relative merits of this emerging technology compared to the traditional “rack-and-stack” (R&S) approach is a subject of some controversy. This paper discusses the primary issues and reviews current progress of surface-emitting arrays relative to the more traditional approach. There are two basic types of monolithic SEAs. In Type I SEAs the laser resonator is parallel to the emitting surface; whereas, for type II, the laser resonator is perpendicular to the surface. Type I arrays can be further distinguished by the means of output coupling, either etched 450 mirrors (type IA) or gratings (type IB). In addition, there is an alternative approach in which edge-emitting arrays are mounted on etched BeO or Si heat-spreaders. This hybrid approach results in surface emission but is not a monolithic fabrication process. This paper will examine the relative merits of primarily type IA SEAs compared to the traditional R&S approach