New materials for solid-state lasers

Summary form only given. Laser materials have been developed for various wavelengths (near infrared, visible, UV) and power regimes (mW to multi-kW). Special geometries of the active material (microchip, rod, disc, fiber) strongly correlate with the active ion concentrations and cross sections of absorption and gain transitions. In the near infrared spectral region high efficiencies have been achieved with diode pumped oxide and fluoride laser crystals doped with rare earth ions are of highest interest. Especially the Yb/sup 3+/ ion exhibits very small Stokes-losses and minimum heat generation. New laser crystals based on sesquioxides possess thermal conductivities higher than that of the well established laser host YAG. Transition metal doped crystals offer broadly tunable radiation within the spectral region 680 nm to 3000 nm. In the visible region Er/sup 3+/, Tm/sup 3+/, and Pr/sup 3+/-doped laser materials operate at several red, green, and blue transitions with laser diode up-conversion pumping. In summary, the research on laser materials has created a number of compact, efficient laser sources for a large variety of applications.