Blue Laser Diode Wavelength Selection With a Variable Reflectivity Resonant Mirror

A guided-mode resonance filter is designed and fabricated for externally locking a GaN blue laser diode. The external mirror design is polarization selective which allows the reflectivity to be tuned, in order to optimize the output coupling of the cavity. The resonance demonstrates a line-width <0.5 nm, centered at 445.6 nm with an output power in excess of 0.5 W of CW power without temperature control.