RESUMEN
Broadband mid-infrared (B-MIR) thermography using fibre optic waveguides can be critical in real-time imaging in harsh environments such as additive manufacturing, personalised medical diagnosis and therapy. We investigate the polarisation effect on thermal measurements through poly-crystalline fibre bundle employing a simple broadband cross-polarisation configuration experimental set-up. Silver halide poly-crystalline fibres AgCl1-xBrx (0 ≤ x≤1) (AgClBr-PolyC) have very wide transmission bandwidth spanning over the spectral range from 1 µm up to 31 µm FWHM. Moreover, they are non-toxic, non-hygroscopic, with relatively good flexibility, which make them very adequate for spectroscopic and thermal measurements in medical and clinical fields. In this study, we used a fibre bundle composed of seven single AgClBr-PolyC fibres, each with a core diameter of about 300 µm, inserted between two broadband MIR polarisers. A silicon carbide filament source was placed at the entrance of the fibre bundle, while a FLIR thermal camera with a close-up lens was employed to measure the spatial temperature distribution over the fibre-bundle end. Indeed, polarisation dependence of temperature measurements has been clearly observed in which the orientation of temperature extrema (minima and maxima) vary from one fibre to another within the bundle. Moreover, these observations have enabled the classification of AgClBr-PolyC fibres following their polarisation sensitivities by which some fibres are relatively highly sensitive to polarisation with polarisation temperature difference (PTD) that can reach 22.1 ± 2.8 °C, whereas some others show very low PTD values down to 3.1 ± 2.8 °C. Many applications can readily be found based on the advantages of both extreme cases.
RESUMEN
Measurements of the refractive indices and the full set of longitudinal acousto-optical figures of merit in an orthorhombic single-crystal indium iodide (InI) were carried out. The high acousto-optic characteristics (M2 up to 1100×10-15s3kg-1) and strong optical anisotropy (Δn=0.47) make it possible to design various types of high-performance acousto-optic devices of the middle and far-infrared spectral range. In combination with a wide transparency range (0.62-51µm), the obtained characteristics make the crystal extremely promising in comparison with most existing analogs.
RESUMEN
Using the Michelson technique we measured the refractive indices for the plane-parallel thin plates made of AgCl1-xBrx(0≤x≤1) and, to the best of our knowledge, for the first time for the Ag0.95Tl0.05Br0.95I0.05 plate, manufactured by hot embossing, at 632.8 nm. We recorded their absorption spectra within the range of 0.19-41.67 µm using UV-Vis spectrophotometry and Fourier transform infrared spectroscopy, which demonstrated that the increase of substituent silver bromide or thallium monoiodide mole fraction in the corresponding solid solution causes the optical density to grow. As the result it moves the transmission edges toward longer wavelengths, while slightly reducing the transmission peak.
