We recently demonstrated a simple time-domain CARS microscopy method called Fourier transform CARS (FTCARS) (read about it here). FTCARS has a number of advantages: it uses a single laser source, and provides essentially unlimited spectral resolution for CARS imaging over a broad spectral range. Because FTCARS is a time-domain technique it effectively eliminates nonresonant background problems faced by all CARS microscopies. Most CARS methods image a single CARS mode, prohibiting them from following multiple chemical species simultaneously.


We have been working to improve the sensitivity of FTCARS microscopy to permit imaging of biological molecules that are found in low concentrations. We have implemented an interferometric detection scheme that provides an order of magnitude amplification of the CARS signal (read about it here and here).


To study the possibilities and limitations of coherent Raman imaging for biological applications we recently performed a comparison between imaging based on spontaneous Raman and coherent Raman scattering. Contrary to the commonly-held belief in the literature, coherent Raman methods often provide little sensitivity advantage for imaging samples with low concentrations and low damage thresholds (read about it here).

Coherent Raman Microscopy