Fundamental and applications of ultraviolet Zinc Oxide Nanowire Lasers

Today, ZnO nanowire lasers are widely used for new applications in optical information processing and computing, and also as excitation sources in medical and biological researches. Therefore, in the paper, the ZnO laser with a lasing wavelength in the near ultraviolet region (350 to 400 nm) is investigated. ZnO nanowires with the wurtzite crystal structure are considered as the active medium of the laser, and the optical characteristics and the basis of generated radiations at the output of the laser are analyzed. Studies show that the structural defects of the active medium of a ZnO ultraviolet laser should be reduced as much as possible to achieve lasing. Also, the light-matter interactions in ZnO nanostructures are significantly stronger than in macroscopic crystals, and this optical property is influenced by the energy bandgap, size, shape, orientation, and crystallinity of the ZnO nanowire. A single ZnO nanowire can be used as a waveguide or resonator due to the difference in its refractive index with the surrounding medium, and the resonant modes depend on the dimensions of the nanowire.