Abstract

Photonic crystal fiber (PCF) greatly enhances light-matter interactions at path lengths much longer than those in conventional sample cells. The overlap between guided modes and fluid samples introduced into the hollow channels in PCF permits quantitative absorption spectroscopy with small (<1 μL) sample volumes [1-2]. Recently, enhanced fluorescence detection was demonstrated in index-guiding PCFs surface-coated with fluorescent antibodies [3] and fluorophores [4] as well as in hollow-core PCFs in which only the hollow core is filled with liquid [5]. This last example results in highly multimode guidance by total internal reflection, yielding transverse intensity patterns that are difficult-to-control and in general axially varying.

© 2011 Optical Society of America