Spectroscopic Characteristics of Triply Vibrationally Enhanced Four-Wave Mixing Spectroscopy

Abstract

Triply vibrationally enhanced (TRIVE) four-wave mixing is a fully resonant, frequency domain spectroscopy that is capable of coherent multidimensional vibrational spectroscopy. TRIVE has 12 different coherence pathways that differ in their time ordering and resonances. The pathways are the coherent analogue to two-color pump−probe pathways. Specific pathways or sets of pathways can be chosen by appropriate selection of time delays and resonance conditions. The pathways have characteristic positions and line shapes in three-dimensional frequency space and their coherent interference has consequences in interpreting the spectra. The line shapes and the relative intensities of different pathways are dependent on the population relaxation and dephasing rates. The different pathways also have different capabilities for line-narrowing inhomogeneously broadened transitions. The narrowing is controlled by the interference between pathways and the quantum level interference between different parts of the inhomogeneously broadened envelope. We also show that selection of the output frequency in two-color TRIVE methods constrains the selection rules that control the relative transition probabilities of the four transitions.