Mid-infrared supercontinuum generation in the fingerprint region

The mid-infrared spectral region is of great technical and scientific interest because most molecules display fundamental vibrational absorptions in this region, leaving distinctive spectral fingerprints. Here, we demonstrate experimentally that launching intense ultra-short pulses with a central wavelength of either 4.5 µm or 6.3 µm into short pieces of ultra-high numerical-aperture step-index chalcogenide glass optical fibre generates a mid-infrared supercontinuum spanning 1.5 µm to 11.7 µm and 1.4 µm to 13.3 µm, respectively [1]. This is the first experimental demonstration to truly reveal the potential of fibres to emit across the mid-infrared molecular fingerprint region, which is of key importance for applications such as early cancer diagnostics, gas sensing and food quality control.