Abstract: An apparatus and a method for coherent multi-dimensional optical spectroscopy employs a beam splitter for splitting a base light pulse into at least first to fourth light pulses, three of which are suitable for interaction with a sample, lens system focuses the first to fourth light pulses at a sample site, and an optical delay varies the arrival times of the first to fourth light pulses at the sample. A detector detects an interference signal. The beam splitter is a non-diffractive optical element. The light pulses, at least along part of their light paths, are guided pairwisely such that changes in the optical path length due to vibration of the beam splitter or due to the delay element are identical for each pair of pulses, where the pulse pairs compensate for any change in the interference signal due to a change of the arrival times of the pair of pulses.

Abstract: An optical assembly for use in coherent two- or more-dimensional optical spectroscopy includes a beam splitter that splits a base light pulse into first, second, third and fourth light pulse and a delay element that varies the arrival times of the first to fourth light pulses at a sample location with respect to each other. The beam splitter includes a cross-grating a first reflector arranged to receive the first to fourth light pulses emerging from the cross-grating and to reflect the same in parallel to each other, a second reflector arranged to receive the first to fourth light pulses from the delay element and to focus the same at the sample location, wherein the delay element is arranged between first and second reflectors. Also shown is an apparatus including such optical assembly and a method for carrying out two- or more-dimensional optical spectroscopy using the assembly.

Abstract: An optical assembly for use in coherent two- or more-dimensional optical spectroscopy includes a beam splitter that splits a base light pulse into first, second, third and fourth light pulse and a delay element that varies the arrival times of the first to fourth light pulses at a sample location with respect to each other. The beam splitter includes a cross-grating a first reflector arranged to receive the first to fourth light pulses emerging from the cross-grating and to reflect the same in parallel to each other, a second reflector arranged to receive the first to fourth light pulses from the delay element and to focus the same at the sample location, wherein the delay element is arranged between first and second reflectors. Also shown is an apparatus including such optical assembly and a method for carrying out two- or more-dimensional optical spectroscopy using the assembly.

Abstract: An apparatus and a method for coherent multi-dimensional optical spectroscopy employs a beam splitter for splitting a base light pulse into at least first to fourth light pulses, three of which are suitable for interaction with a sample, lens system focuses the first to fourth light pulses at a sample site, and an optical delay varies the arrival times of the first to fourth light pulses at the sample. A detector detects an interference signal. The beam splitter is a non-diffractive optical element. The light pulses, at least along part of their light paths, are guided pairwisely such that changes in the optical path length due to vibration of the beam splitter or due to the delay element are identical for each pair of pulses, where the pulse pairs compensate for any change in the interference signal due to a change of the arrival times of the pair of pulses.