Nonlinear Index of refraction of germanium selenide glass at 10.6 μm

We report on the nonlinear index of refraction in germanium selenide glasses at the CO 2 laser wavelength of 10.6 μm. This frequency is near the low frequency edge of the germanium selenide infrared window. The nonlinear index is measured by the z-scan technique probed with a CO 2 laser. The measurements were done with the laser operating in both continuous and pulsed modes. Compositions of germanium selenide glasses varying from 2 to 40 at. % germanium are studied and the data is compared to the structure and infrared spectra of these glasses.