Comparing coherent and spontaneous Raman scattering under biological imaging conditions

We compare imaging based on coherent and spontaneous Raman scattering (SpRS) under conditions relevant for biological imaging. Using a broadband laser source, we perform spectral domain imaging of polystyrene beads using coherent Stokes Raman scattering and SpRS and find comparable signal levels. Short interaction lengths, low molecule number, and low incident power all reduce the advantages available with coherent Raman methods. We present calculations to support our measurements. (C) 2009 Optical Society of America