Chemically selective imaging by spectral phase shaping for broadband CARS around 3000 cm^−1

Abstract

Chemically selective microscopy based on broadband coherent anti-Stokes Raman scattering (CARS) is demonstrated on a mixed sample of 4 μm diameter polystyrene (PS) and poly (methyl methacrylate) (PMMA) beads. The CARS signal from the PS or the PMMA beads is enhanced or suppressed, depending on the phase profile applied to the broadband spectrum. Using a combination of negative and positive (sloped) π-phase steps the purely nonresonant background signal is removed.