Raman spectrograms in fifth order coherent Raman scattering: The sequential CARS process in liquid benzene

The first Raman spectrograms are reported for fifth order coherent anti-Stokes Raman scattering. The 992 cm−1 `ring breathing' mode of liquid benzene is examined using broadband, nontransform-limited, quasi-cw noisy laser light. The fifth order signal is entirely dominated by a sequential CARS process called I(3)SCARS. The vibrational Raman frequency and the dephasing rate constant for this mode is extracted from combined I(3)SCARS and I(2)CARS spectrograms with high precision and potentially high accuracy.