Super continuum (SC) generation is a nonlinear phenomenon characterised by dramatic spectral broadening of intense light passing through a nonlinear material. SC generation occurs in various media and may find use in numerous applications such as spectroscopy or ultra-short-pulse generation. Spectral slicing of a generated SC is an elegant way of replacing multiple light sources having separate wavelengths.
Many prior art SC light sources are based on micro structured fibres (MF) which posses unique optical properties with a large degree of freedom of design thus allowing for optimization of the fibre for SC generation. However, SC generation in standard fibre has also been demonstrated. Most prior art disclosures of SC sources utilise femto-second (fs) pulses (10−15 s) to generate the SC. The physical mechanism responsible for the SC generation is believed to be due to multiple nonlinear processes. It has also been shown that it is possible to create SC by use of pico- and nanosecond pulses, and the mechanism responsible for these SCs is often attributed to a combination of four wave mixing and stimulated Raman scattering. In either case of pump duration and/or fibre type, the size of the guiding core has been relatively small (<6 μm diameter) to ensure a high optical density in the core so that non-linear effects are maximized. This limits the optical power with which the fibre may be pumped either due to the damage threshold of the end facet of the fibre or the damage threshold of the fibre core. The optical power may also be limited by the availability or cost of a high power laser having an output with a sufficient beam quality to allow a substantial amount of its output to enter the fibre.