Mid-infrared filamentation-induced supercontinuum in As–S and an As-free Ge–S counterpart chalcogenide glasses

We experimentally investigate supercontinuum generation in conventional As2S3 and GeS3 bulk chalcogenide glass materials pumped by high-power mid-infrared femtosecond pulses. Mid-infrared supercontinuum spectra are successfully reported through the filamentation of µJ-level energy pulses at wavelengths close to the bulk’s zero dispersion wavelength, i.e., in both normal and anomalous dispersion regimes. The main features of our results are twofold. On the one hand, a GeS3 non-toxic As-free glass is successfully conceived and proved suitable for mid-infrared supercontinuum generation. On the other hand, 3.3-mm-long bulk samples are sufficient to enable the spectral coverage from 2.5 to ~11 µm in a 20-dB dynamic range, thus reaching the multiphonon absorption edge for both chalcogenide glasses.