Enhanced fluorescence sensing using microstructured optical fibers: a comparison of forward and backward collection modes.

A general model of excitation and fluorescence recapturing by the forward and backward modes of filled microstructured optical fibers (MOFs) is presented. We also present experimental results for both backward and forward fluorescence recapturing within a MOF as a function of fiber length and demonstrate a good qualitative agreement between the numerical model and experimental results. We demonstrate higher efficiency of fluorescence recapturing into backward modes in comparison with that of forward modes.