In-fiber light-fluorophore interactions for spectroscopy and photochemistry

Abstract

Optical fibers have enabled the miniaturization of a host of optical devices and systems. The further development of photonic crystal fibers (PCFs) has broadened this miniaturization capability to fluidics. Exploiting the optofluidics offered by PCFs, in-fiber light-fluorophore interactions have been studied in this thesis for applications in fluorescence spectroscopy and the generation of photochemical reactions. This first entailed the devise of an optofluidic platform that facilitated the studies. The PCF component was further bent to increase the extent of interaction between the guided light and the infiltrated contents. A ray-tracing model was subsequently developed and accounted for the heightened light-fluorophore interactions within bent PCFs. This, together with a ratiometric method of spectral analysis, enabled fluorospectroscopy to be performed using a low-cost light source, in a compact all-fiber regime. The further generation of photochemical reactions within PCFs then allowed for in-fiber surfaces to be functionalized with biomolecules. This enabled the immobilization of fluorescent dye-loaded liposomes, where their close proximity to the guided light facilitated optical excitation and subsequent analysis using means of fluorospectroscopy. This successful integration of liposomes with optical waveguides highlighted feasibility in the further development of bio-integrated photonic devices.