Fast-to-slow axis mode imaging for brightness enhancement of a broad-area laser diode array.

Broad-area laser (BAL) diodes have found use in numerous applications requiring multi-watt powers, but remain limited by poor spatial beam quality. A novel laser cavity that enhances the brightness of a BAL array has been demonstrated. Wavelength beam combining (WBC) is used to spatially overlap output from the emitters. Improved beam quality is achieved by imaging the fast-axis mode onto the slow axis of the BAL array. The brightness is enhanced twofold over a typical Littman-Metcalf WBC cavity, reaching 47 MW·cm(-2)·sr(-1) at an output power of 1.16 W.