We demonstrate that pulse shaping of a probe pulse can suppress the nonresonant background (NRB) contribution and retrieve resonant Raman signal efficiently in broadband coherent anti-Stokes Raman scattering (CARS) spectrum. A pulse shaper prepares a probe pulse with two spectral components of differing phase. When the CARS fields generated by these two out-of-phase components are optically mixed, NRB signal is greatly reduced while a resonant CARS signal remains with minimal attenuation. We discuss three model schemes for the interfering pulse components: (1) two pulses with different bandwidths and the same center frequency (ps-fs scheme); (2) two pulses with the same bandwidth and shifted center frequencies (ps-ps scheme); and (3) a pulse with different phases across the center frequency (fs(+/-) scheme). In all schemes, only the resonant signal from the 3-color CARS mechanism survives. The resonant signal from 2-color CARS mechanism vanishes along with the NRB. We discuss optimization conditions for signal intensity and shape of resonant CARS peaks
Multiphoton Microscopy in the Biomedical Sciences IX
and Cicerone, M.
Pulse shaping for background free broadband CARS, Multiphoton Microscopy in the Biomedical Sciences IX, San Jose, CA, US, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=901242
(Accessed December 2, 2023)