CW lasing of current injection blue GaN-based vertical cavity surface emitting laser

Here, we report the cw laser operation of electrically pumped GaN-based vertical cavity surface emitting laser (VCSEL). The GaN-based VCSEL has a ten-pair $\mathrm{In}\mathrm{Ga}\mathrm{N}∕\mathrm{Ga}\mathrm{N}$ multiple quantum well active layer embedded in a GaN hybrid microcavity of $5\lambda$ optical thickness with two high reflectivity mirrors provided by an epitaxially grown $\mathrm{Al}\mathrm{N}∕\mathrm{Ga}\mathrm{N}$ distributed Bragg reflector (DBR) and a ${\mathrm{Ta}}_2{\mathrm{O}}_5∕\mathrm{Si}{\mathrm{O}}_2$ dielectric DBR. cw laser action was achieved at a threshold injection current of $1.4\mathrm{mA}$ at $77\mathrm{K}$ . The laser emitted a blue wavelength at $462\mathrm{nm}$ with a narrow linewidth of about $0.15\mathrm{nm}$ . The laser beam has a divergence angle of about 11.7° with a polarization ratio of 80%. A very strong spontaneous coupling efficiency of $7.5\times {10}^{-2}$ was measured.