Resonantly enhanced coherent anti-Stokes Raman scattering

Resonant coherent Raman spectroscopy based on electronic transitions is known for over 40 years to provide chemically specific information from molecules at micromolar concentrations. Unfortunately, live-cell and tissue imaging becomes challenging at shorter wavelength due to reduced threshold for cell damage and significantly increased light scattering. Thus, we evaluate resonant enhancement of vibrational transitions, which can be selectively excited to promote either stronger signal or to provide better selectivity of molecular excitation. We experimentally validate several new excitation schemes for coherent anti-Stokes Raman scattering imaging and discuss their pros and cons.