Tunable visible lasers using defects in oxides

Continuous-wave laser action using F(+) centers in CaO crystals is reported in the blue range of the visible spectrum. These centers may be pumped by using either Ar(+) or N2 laser lines. The laser is tunable in the range 357-420 nm with an output power of 15 mW at the band center for an input power of 100 mW. F centers are also reported to give laser action in the wavelength range 574-625 nm.