Optically Pumped Lasing at 353 nm Using Non-polar a-plane AlGaN Multiple Quantum Wells over r-plane Sapphire

Abstract

We report an optically-pumped alternative nitride-based laser with room-temperature emission at 353 nm. The active region comprised of non-polar a-plane Al_0.04Ga_0.96N/Al_0.08Ga_0.92N multiple quantum wells whereas the lasing cavity consisted of Al_0.15Ga_0.85N clad and Al_0.10Ga_0.85N waveguide layers and naturally cleaved facet mirrors. The layers were grown over r-plane sapphire substrates by metalorganic chemical vapor deposition technique. A room temperature lasing threshold for N₂-laser photoexcitation of 110 kW/cm² and a modal optical gain of 215 cm^-1 was measured at the peak emission wavelength.