Thermal and laser properties of Nd:Lu3Sc1.5Ga3.5O12 for high power dual-wavelength laser.

ABSTRACT

We measured the thermal properties of NdLu3Sc1.5Ga3.5O12 (NdLuSGG) crystal, including the thermal expansion coefficient, specific heat, and thermal diffusion coefficient. The calculated thermal conductivity is 4.4 W/mK at room temperature. A high-power continuous-wave and passively Q-switched NdLuSGG laser was also demonstrated. Continuous-wave output power of 6.96 W is obtained which is the highest power with this material. For the first time to our knowledge, the passively Q-switched NdLuSGG laser is reported with the shortest pulse width, largest pulse energy, and highest peak power are achieved to be 5.1 ns, 62.5 µJ, and 12 kW, respectively. By spectral analysis, it has been found that the NdLuSGG laser was located at 1059 nm under low pump power, and became dual-wavelength at 1061.5 and 1059 nm when the incident pump power is over 2.27 W. The generating mechanism of dual-wavelength laser is also discussed.