Single-Shot Fourier-Slice Dual-Comb Spectroscopy

Multidimensional coherent spectroscopy is a powerful method for studying materials’ optical properties. It also has potential to be used for chemical sensing applications as it allows the measurements of samples’ energy level structures as well as couplings between the excited states resonances. This coupling information is the key to identify whether or not the sample contains a mixture of analytes. Coupling information is not easily accessible using one-dimensional linear or non-linear methods, necessitating more complex multidimensional experimental techniques. However, multidimensional techniques require bulky apparatus, complex stabilization schemes, and/or long acquisition times that prevent them from being used outside the lab. Here we propose and demonstrate a new and simple approach that enables the measurements of the main absorption lines as well as the couplings between the excited states resonances extremely fast (tens to hundreds of
$\mu \text{s}$
) without measuring the full multidimensional spectra. This approach is based on the Fourier-slice theorem and was inspired by frequency comb technology, particularly dual-comb spectroscopy. Our approach uses free-running lasers and co-linear geometry, and with the development of compact lasers this approach can become field-deployable for sensing applications. We demonstrate the concept on rubidium vapor.