Interaction of Light with Matter in Optical Fibre Sensors

This chapter discusses the main ways light interacts with matter from a biomedical engineering perspective. It explains the basic concepts such as photon energy and physicochemical processes, covering interactions of photons with atoms and molecules, with an emphasis on photobiology and the multiplicity of the different de‐excitation processes. The chapter discusses elastic and inelastic scattering and their application to optical fibre sensing. It mentions recent developments in integration of optical fibres with other devices, which provide new engineering opportunities for innovative interactions of light with matter. The chapter proposes methods to enhance the signal to noise ratio in experiments, especially localised field enhancement for improved sensitivity. Finally, it discusses the intriguing prospect of molecular control using femtosecond pulse shaping to control rather than just observe interactions of light with matter.