Photosensitivity of solgel-derived germanosilicate planar waveguides

Abstract

The effects of controlled atmosphere heat treatments on the photosensitivity and UV absorption of GeO(2)-SiO(2) solgel planar waveguides are presented. Photoinduced refractive-index changes in the samples are deduced from photosensitive grating writing experiments and are found to be of the order of those seen in some fiber experiments. A correlation is seen between the sample sensitivity and the strength of the absorption at 242 nm, providing insight into the possible mechanisms governing photosensitive processes in these materials.

Accurate measurement of the refractive index of CO2, N2, He, O2, and air at 10.57μ and T=23°C

“…We see that there is an appreciable difference with the results obtained for [1] regarding CO 2 and N 2 . On the contrary, our data well agree with the results obtained for [3] regarding He and N 2 as long as we consider that both these molecules to have a weak dispersion in the infrared.…”

“…reported in [7]) that has considered the contribution of the infrared resonance. On the contrary the theoretical value of Old agrees with [1]. It is possible that the ''normal'' dispersion contribution of the 4.3 lm band to the 10 lm refractive index is compensated by the ''anomalous'' dispersion of the 15 lm band that is 12 times weaker but also 4 times closer.…”

“…Nevertheless it is possible that the data of [1] are instrumentally overestimated. In fact the data reported in Table 2 show that in [1] the N 2 and CO 2 coefficients measured at 0.633 lm are clearly overestimated with respect to the more accurate results of [3].…”

“…Only the refractive index of CO 2 and N 2 have been measured with good accuracy in this region [1]. The knowledge of these components of the CO 2 laser mixture is important in the emission dynamics of the CO 2 laser [2].…”

Photosensitive point defects in optical glasses: Science and applications

“…Photosensitive planar waveguides have been formed using a variety of synthetic approaches including PECVD [33,34], sol-gel [35][36][37], flame hydrolysis [38], and sputtering [39-4 1]. These efforts have resulted in photosensitive effects arising from phenomena including absorption band bleaching/growth and mechanically based mechanisms associated with structural relaxation driven by local stress/strain fields that lead to changes in volume and polarizability.…”