Multimaterial mid-infrared transmitting fibre bundle for thermal imaging

Thanks to the continuous progress of Mid-Infrared (MIR) detectors, related electronics and lenses, thermal imaging has now become a standard inspection technique in numerous industrial sectors, as well as in biomedical science and defence. Fibre endoscopy is a well-developed technology and often a critical component for imaging inaccessible areas. So far, the development of a MIR version that can be applied to thermal rather than optical imaging has proved challenging. Despite its large potential scientific and industrial impact, no commercial product is yet available on the market. Several fabrication approaches have been proposed over the years, using a broad range of material combinations [1, 3]. However, the overall performance of these bundles has been so far limited in terms of either optical properties (loss, size, cross-talk, _), compactness or mechanical flexibility. Indeed, the challenge consists in combining adequate materials, adopting suitable optical design engineering and developing a manufacturing process.