Introduction

Continua generated using high pulse energy laser systems to create broad spectra (Alfano and Shapiro, 1970) have been used for spectroscopy for many years (e.g. Busch et al., 1973). The application of fibre-generated continua to spectroscopy was suggested as early as 1976 in work by Lin and Stolen (1976) where a continuum spanning ∼450–600 nm was generated in a step-index fibre pumped by a nitrogen pumped dye laser. Since the demonstration of supercontinuum generation in microstructured optical fibres (MOF), however, the range of spectroscopic and imaging applications has increased enormously, owing to the high average powers, unprecedented spectral width and relatively low cost and low complexity of such sources. This chapter specifically focuses on the applications of supercontinua generated in MOFs and, in particular, on applications in biophotonics.

MOF supercontinuum sources can be broadly grouped into three categories according to whether the laser pump source emits femtosecond pulses, picosecond–nanosecond pulses or cw radiation. In general terms, sub-ps pulses can produce broad supercontinua spanning from the UV to the NIR but the peak intensity damage threshold at the input end of the microstructured optical fibre limits the maximum average power that can be obtained in the supercontinuum to ∼<0.5 W with typically ∼<0.5 mW/nm available in the visible spectrum. The use of pump lasers with longer ps–ns pulses can significantly increase the maximum available average power before the onset of damage in the MOF such that high power supercontinua with several mW/nm in the visible can be achieved (e.g. Rulkov et al., 2005).