Blue-Violet Lasing of Optically Pumped GaN-Based Vertical Cavity Surface-Emitting Laser With Dielectric Distributed Bragg Reflectors

Optically pumped GaN-based vertical cavity surface-emitting laser (VCSEL) with two Ta₂O₅/SiO₂ dielectric distributed Bragg reflectors (DBRs) was fabricated via a simplified procedure: direct deposition of the top DBR onto the GaN surface exposed after substrate removal and no use of etching and polishing processes. Blue-violet lasing action was observed at a wavelength of 397.3 nm under optical pumping at room temperature with a threshold pumping energy density of about 71.5 mJ/cm². The laser action was further confirmed by a narrow emission linewidth of 0.13 nm and a degree of polarization of about 65%. The result suggests that practical blue-violet GaN-based VCSEL can be realized by optimizing the laser lift-off technique for substrate removal.