Development of Nd,Cr co-doped laser materials for solar-pumped lasers

Solar-pumped lasers have attracted attention in the area of renewable energy creation. However, since the conversion efficiency from solar energy to laser energy is low, such lasers are not yet in practical use. In this work, we grew and evaluated Nd3+,Cr3+-co-doped YVO4 and CaYAlO4 crystals for solar-pumped lasers. We succeeded in dramatically increasing the absorption from the ultraviolet to visible region using both crystals. The maximum absorption coefficient was 58 cm(-1) at 402 nm for 1.0 at. % Cr-co-doped Nd:YVO4 crystal. The absorption coefficient of Nd,Cr:CaYAlO4 reached 52 cm(-1) at 430 nm in the case of 0.1 at. % Cr doping. Strong fluorescence at 1 mu m was observed upon pumping Nd,Cr:YVO4 at 400 nm. The result indicates effective energy transfer from Cr to Nd occurred in the Nd,Cr:YVO4. (C) 2014 The Japan Society of Applied Physics