Near infrared to ultraviolet (UV) and visible upconversion luminescence was observed in ZnO single crystalline under femtosecond laser irradiation. The optical properties of the crystal reveal that the UV and visible emission band are due to the exciton t
The basic propagation properties of the silica and silicon subwavelength-diameter hollow wire waveguides have been investigated by comparison. It shows that the silica and silicon subwavelength-diameter hollow wire waveguides have some interesting propert