Wavelength Selection and Polarization Multiplexing of Blue Laser Diodes

An external laser cavity was constructed that utilizes polarization multiplexing to combine the emission from two gallium nitride blue laser diodes. A polarization-dependent narrow-band resonant mirror was designed to be the output coupler of this cavity, which locked both laser diodes at a fixed wavelength of 445.5 nm with a line-width of <0.5 nm. Output powers from this system approached 0.7 W while maintaining complete spectral control.