Metal-oxide-SiO/sub 2/ composite ZnO lasers

The use of metal-oxide-SiO/sub 2/ composite to sustain random lasing in ZnO thin films is proposed. It is shown that the presence of stripe pattern in the metal-oxide-SiO/sub 2/ composite is necessary to minimize lasing threshold and achieve directional emission. By controlling the concentration of the metal-oxide and stripe spacing, coherent lasing threshold and linewidth of /spl sim/85 kW/cm/sup 2/ and /spl sim/0.4 nm, respectively, can be obtained from mirrorless ZnO thin-film waveguide lasers.