Frequency combs enable rapid and high-resolution multidimensional coherent spectroscopy.

Lomsadze, Bachana; Cundiff, Steven T · Science · 2017

basic_science · Level V

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Abstract

Dual laser frequency combs can rapidly measure high-resolution linear absorption spectra. However, one-dimensional linear techniques cannot distinguish the sources of resonances in a mixture of different analytes, nor can they separate inhomogeneous and homogeneous broadening. Here, we overcame these limitations by acquiring high-resolution multidimensional nonlinear coherent spectra with frequency combs. We experimentally differentiated and assigned the Doppler-broadened features of two naturally occurring isotopes of rubidium atoms (<sup>87</sup>Rb and <sup>85</sup>Rb) according to the placement of their hyperfine energy states in a two-dimensional spectrum.