KubarychGroup
J. M. Anna, M. J. Nee, C. R. Baiz, R. McCanne, K. J. Kubarych, J. Opt. Soc. Am. B 27 (2010) 382-393
Chirped-pulse upconversion (CPU) enables the detection of mid-infrared spectra using a silicon CCD camera by sum-frequency mixing a mid-IR field with a highly-chirped near-IR (800 nm) field. Although the substantial chirp limits spectral broadening and phase distortions caused by the inherent cross-phase modulation, the exquisite phase fidelity needed to measure a fully absorptive two-dimensional IR spectrum demands correction of the phase distortions. We demonstrate how to correct all of the phase distortions involved in recording an absorptive 2DIR spectrum, including delay stage calibrations as well as the requisite nonlinear signals. Besides the extra experimental step of the upconversion process itself, the phase correction procedure requires only knowledge of the spectral or temporal phase of the chirped pulse. The method is demonstrated in a metal carbonyl complex, Mn2(CO)10, in n-hexane and methanol solvents, showing that the method operates well in cases of both homogeneous and inhomogeneous broadening.
12/20/09