Determining the continuous thermo-optic coefficients of chalcogenide glass thin films in the MIR region using FTIR transmission spectra.

A new method (FTIR continuous dn / dT method, n is refractive index and T temperature) for measuring the continuous thermo-optic coefficients of thin transparent films in the mid-infrared (MIR) spectral region is introduced. The technique is based on Fourier transform infrared (FTIR) transmission spectra measured at different temperatures. It is shown that this method can successfully determine the thermo-optic coefficient of chalcogenide glass thin films (of batch compositions GeSbSe at.

Experimental observation of gain in a resonantly pumped Pr-doped chalcogenide glass mid-infrared fibre amplifier notwithstanding the signal excited-state absorption.

We demonstrate a maximum gain of 4.6 dB at a signal wavelength of 5.28 μm in a 4.