Thermal properties of a solid-state laser crystal LiNdP4O12

The thermal expansion coefficient and the thermal coefficient of refactive index of a stoichiometric laser crystal LiNdP4012 have been measured from room temperature to 250 °C. The thermal coefficient of refractive index of the crystal is negative and its average value over three crystallographic axes is about −2×10−6 deg. The diffusivity and heat capacity of the crystal have been measured by laser flash method from room temperature to 300 °C. Using this information, thermal conductivity of the crystal has been calculated. The largest thermal conductivity of the crystal was 3.3×10−2 J/cm s deg along crystallographic b axis. The temperature distribution observed in a 300-mm-thick crystal plate irradiated by Ar laser light is explained by the thermal conductivity obtained through these experiments.