Friday 03 Feb 2012Colloquium: Vibrational Molecular Interferometry

Prof. Herman Offerhaus - U. of Twente, Netherlands

Newman F 12:00-13:00

We demonstrate an implementation of nonlinear optical (CARS) microscopy that is based on an interaction picture centered on the molecules, rather than the interacting fields, as proposed in[1]. This approach requires a new way of thinking about the interaction that I will discuss. It provides an intuitive and unified description of the various signal contributions, allowing easy extraction of the vibrational response.
Three optical fields create a pair of Stokes Raman pathways that interfere in a single vibrational state. Frequency modulating two of the fields leads to amplitude modulations of the signals, which we refer to as vibrational molecular interferometry (VMI). The modulation depth that we observe is comparable to that found in SRS, and allows imaging at high speed free of the non-resonant background that plagues coherent anti-Stokes Raman scattering (CARS) measurements.

[1] Rahav, S. & Mukamel, S. Stimulated coherent anti-Stokes Raman spectroscopy (CARS) resonances originate from double-slit interference of two-photon Stokes pathways. Proceedings of the National Academy of Sciences of the United States of America 107, 4825-4829, doi:DOI 10.1073/pnas.0910120107 (2010).

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