Diode pumped visible Dy3+-doped silica fiber laser: Ge-co-doping effects on lasing efficiency and photodarkening

We present the first demonstration of visible laser oscillation in the Dy3+-doped silica fiber pumped by a 451nm InGaN laser diode. It was found that Ge-co-doping plays the following important roles of laser oscillation: (1) to reduce the Rayleigh scattering loss, (2) to suppress the X-ray-induced and pump-induced photodarkening (PD), and (3) to increase lasing slope efficiency. In a fiber with 0.46wt% Dy, 1.8 wt% Ge, and 0.54wt% Al, the slope efficiency is 22.0 % at 582.5 nm, and the maximum output power is 18.4 mW.

Recent development of UV-B laser diodes

This review paper describes the history of development, current issues, and future expectations of UV-B laser diodes, which are expected to be adopted in various applications such as microfabrication and biotechnology in the near future. In order to achieve room temperature operation of this device, there were several challenges are remained, including the development of a crystal growth technique of high crystalline quality AlGaN that enables a laser oscillation with a low excitation carrier density, and the development of a semiconductor layer structure that simultaneously formation of a desirable optical cavity and injection of high density carriers (operation of high current density) to active layer allowing for laser oscillation. These challenges and the technologies that have overcome them are reviewed. Current status of the device characteristics and future challenges are also discussed.

Random laser oscillation from an organic fluorescent dye loaded inside a porous zirconia medium

Porous zirconia medium as a porous scatterer was superior to zirconia microparticles with respect to random laser oscillation.