Coherent Raman scattering with incoherent light for a multiply resonant mixture: A factorized time correlator diagram analysis

Abstract

Coherent Raman scattering using broadband, incoherent (noisy) light (termed ${\mathrm{I}}^{(2)}\mathrm{CRS}$---the I for interferometric and the superscript 2 for twice acting noisy fields) is treated for a multiply resonant, multicomponent mixture of molecules. Both the resonant-resonant and resonant-nonresonant hyperpolarizability contributions to the signal intensity are included in this formalism. The emphasis is on the physical understanding of this spectroscopy. To this end, factorized time correlator (FTC) diagram analysis is used to characterize the ${\mathrm{I}}^{(2)}\mathrm{CRS}$ signal. The FTC diagram technique also serves to organize the terms that arise through the stochastic averaging of the noise at the intensity level. In addition to the FTC diagram analysis, a spectral filter analogy is employed to provide further insight into the physics behind ${\mathrm{I}}^{(2)}\mathrm{CRS}.$