Effect of annealing temperature on the thermo-optic properties of holmium doped silica glasses prepared by sol-gel method

Silica based glasses activated by rare earth ions promises to be an efficient material for the photonics applications. Incorporation of holmium as a rare earth dopant finds wide applications in the infrared range of the electromagnetic spectrum. In this work, we report the preparation and the thermo-optic characterization of the holmium doped silica glasses. The samples are prepared via sol-gel route. The structural characterization of the samples is carried out using the X-ray diffraction technique whereas the constituents of the samples are identified using the Fourier Transform Infrared (FTIR) Spectroscopy. The optical properties of the samples are measured using the UV-VIS absorption spectroscopy. The thermal effusivity values of the samples are evaluated using an open cell photoacoustic technique. Influence of the annealing temperature on the thermal as well as the optical properties of the samples is investigated in detail. Analysis of the results shows that the doping and annealing process influences the thermo-optic properties in a substantial manner.