Abstract

Power scaling in the limited compact volume have been interested as a key issue of solid-state micro photonics, precise thermo-mechanical and -optical parameters such as thermal conductivity k, thermal expansion coefficient a, thermal refractive index coefficient dn/dT of laser media are required. A factor of κ/α is proportional to a thermal-shock parameter R_T [1], and thus implies the resistance for thermo-mechanical effects. Similarly a factor of x/(dn/dT) is proportional to the focal length of thermal lens f_T [1]. Since x of laser media are usually estimated by laser-flash method, previously reported values often contained error caused by non one-dimensional thermal conduction and heat transmission through radiation. We proposed qlD-flash method to avoid these error factors [2], and found that x of Nd:YVO₄ is twice the well-known value, and is larger than Nd:GdVO₄ and Nd:YAG. This result indicated that R_T of Nd:YVO₄ should be larger than currently recognized value. In this work we summarized thermal characteristics of YVO₄ with comparative study of GdVO₄ by using of carefully evaluated k, a, dn/dT, thermal heat capacity coefficient dC_p/dT, and thermal conductivity coefficient dk/dT.

© 2007 IEEE