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 CO2 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 CO2 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.