Fabrication and performance of blue GaN-based vertical-cavity surface emitting laser employing AlN∕GaN and Ta2O5∕SiO2 distributed Bragg reflector

GaN-based vertical-cavity surface emitting laser with 3 $\lambda$ cavity and hybrid mirrors, consisting of the 25 pairs $\mathrm{AlN}∕\mathrm{GaN}$ dielectric Bragg reflector and the 8 pairs ${\mathrm{Ta}}_2{\mathrm{O}}_5∕{\mathrm{SiO}}_2$ , was fabricated. The laser action was achieved under the optical pumping at room temperature with a threshold pumping energy density of about $53\mathrm{mJ}∕{\mathrm{cm}}^2$ . The laser emits 448 nm blue wavelength with a linewidth of 0.25 nm and the laser beam has a degree of polarization of about 84%.