High Brightness Diode Lasers Based on Beam Splitting and Polarization Combining

Abstract

A new method to improve the brightness of diode lasers based on beam-waist splitting and polarization combining was proposed and demonstrated. The beam waist was split by a precisely cut prism into two parts and combined with a polarization beam combiner. The advantages of simple setup, high efficiency, brightness, and universality were presented. The slow axis M2 factor of a broad-area diode laser with a ridge beam width of 180 μm was reduced from 18.5 to 9.8, and a brightness of 42.4 MW cm−2 sr−1 was realized; this brightness was a 84.21% improvement of the same emitter at 8 A. The slow axis M2 factor of a commercial broad-area diode laser array combined by spectral beam combining was reduced from 9.08 to 4.78, and 80.6% improvement of brightness was realized on the same commercial broad-area diode laser array. A brightness of 195.8 MW cm−2 sr−1 was realized at 36 A by this diode laser array. This method can be applied in a highly polarized light source to improve the beam quality and brightness.