  We report on the experimental demonstration of the broadband "trapped
rainbow" in the visible range using arrays of adiabatically tapered optical
nano waveguides. Being a distinct case of the slow light phenomenon, the
trapped rainbow effect could be applied to optical signal processing, and
sensing in such applications as spectroscopy on a chip, and to providing
enhanced light-matter interactions. As an example of the latter applications,
we have fabricated a large area array of tapered nano-waveguides, which exhibit
broadband "trapped rainbow" effect. Considerable fluorescence enhancement due
to slow light behavior in the array has been observed.
