Compact implementation of Fourier transform two-dimensional IR spectroscopy without phase ambiguity

We describe an optimized setup for two-dimensional (2D) IR spectroscopy, which can be implemented at low additional cost and with standard optics in any laboratory equipped for femtosecond mid-IR spectroscopy. An interferometer produces a pair of intense pump pulses, whose interferogram is simultaneously recorded and directly yields the relative phase needed for the calculation of absorptive 2D spectra. We analyze different sampling methods based on a realistic noise model and introduce fast population time modulation as an alternative to the use of choppers in the suppression of scatter. Signal levels are compared to those of a photon-echo setup. A compact implementation of Fourier transform 2D-IR spectroscopy without phase ambiguity Jan Helbing and Peter Hamm Physikalisch-Chemisches Institut, Winterthurerstrasse 190, 8057 Zürich, Switzerland We describe an optimized setup for two-dimensional infrared spectroscopy, which can be implemented at low additional cost and with standard optics in any laboratory equipped for femtosecond mid-IR spectroscopy. An interferometer produces a pair of intense pump pulses, whose interferogram is simultaneously recorded and directly yields the relative phase needed for the calculation of absorptive 2D-spectra. We analyze different sampling methods based on a realistic noise model and introduce fast population time modulation as an alternative to the use of choppers in the suppression of scatter. Signal levels are compared to those of a photon echo setup. c © 2010 Optical Society of America OCIS codes: 120.6200, 320.7150