Abstract

Strong refractive index changes (RICs) of electronic origin (due to polarizability differences in the excited and unexcited activator ions) have been experimentally and theoretically studied recently in the case of the laser crystals and glasses doped by Nd³⁺ and Yb³⁺ ions when they are intensively pumped [1,2]. Interferometric and grating testing methods were developed for the registration of the index changes and the separation of the electronic and thermal contributions, and excited-state absorption measurements were performed to estimate the polarizability changes with the aid the Clausius-Mosotti relation. This present communication is devoted to the interferometric measurements of the index changes in Tm-doped laser materials: crystals Tm:YAG and Tm:YLF, and ceramics Tm:Lu₂O₃ under laser pumping.

© 2011 Optical Society of America