Optically pumped GaN/Al0.1Ga0.9N double-heterostructure ultraviolet laser

Molecular-beam epitaxy was used to grow a 100 nm Al0.1Ga0.9N/100 nm GaN/500 nm Al0.1Ga0.9N double heterostructure on a 10-mu m-thick GaN buffer layer grown with hydride vapor phase epitaxy on (0001) sapphire. Lasing from the 100 nm GaN active layer has been obtained at similar to 359 nm at liquid-nitrogen temperature (77 K) and at similar to 365 nm at room temperature (295 K), using transverse optical pumping at 337.1 nm with a 600 ps transversely excited atmospheric pressure pulsed nitrogen laser. Threshold pump fluences were measured to be 0.3 and 0.5 mJ/cm(2) at 77 and 295 K, respectively, for a laser with 65 mu m cavity length. In a laser of 23 mu m cavity length, longitudinal cavity modes were observed with 0.56 nm spacing, corresponding to a group refractive index of 5.0 at the lasing wavelength. (C) 1996 American Institute of Physics.