Two-dimensional vibrational-electronic spectroscopy with a white light probe

Two-dimensional Vibrational-Electronic (2D-VE) spectroscopy provides direct access to the couplings and correlations between vibrational and electronic transitions. We present a Fourier transform 2D-VE setup that employs compressed broadband white-light probing to resolve changes in electronic spectra induced by infrared (IR) excitation. These changes arise from vibronic couplings that are mode- and molecule-specific and can, for example, be used to disentangle congested spectra. As a demonstration, we measure a mixture of laser dyes with strongly overlapping IR spectra but clearly distinguishable dye-specific 2D-VE signatures. Though several novel advanced spectroscopies and microscopies rely on IR-induced modulations of visible spectra, they do not directly measure these effects, which can now be achieved by the present setup for a broad wavelength range from 380 to 700 nm.