Biomedical Applications in Probing Deep Tissue Using Mid-Infrared Supercontinuum Optical Biopsy
This chapter is aimed at stimulating new mid-infrared (MIR) research amongst early-stage researchers in MIR biophotonics, MIR photonics and in MIR glass science and technology. MIR absorption spectroscopy enables interrogation of the molecular structure of matter using MIR radiation. Single molecules, dimers and more extended molecular structures in the gaseous, liquid or solid states all manifest their internal energy in part through constant molecular vibrational motion. In the MIR range, molecular species exhibit fundamental absorption bands with large extinction coefficients thus MIR spectroscopy potentially provides extremely sensitive chemical analysis. Increasing the wavelength from visible to NIR light, enables deeper imaging due to a reduced scattering coefficient, allowing the absorption coefficient to become the main determinant of image quality. A non-subjective classification of spectra was performed by means of linear discriminant analysis which determined the boundaries that best separated classes of tissue type by computing the distance of each spectrum from class centroids.