Rotationally-resolved cavity-enhanced 2DIR spectroscopy*

Detection of trace amounts of molecules in multi-species mixtures is important for many purposes, ranging from chemical dynamics in complex environments to breath analysis. 2DIR spectroscopy is a powerful tool for studying both molecular structure and dynamics. It can provide better selectivity than linear spectroscopy due to the extra degrees of freedom for distinguishing the components of a complex mixture. Application of 2DIR spectroscopy to trace-gas detection has been hindered by insufficient sensitivity and resolution of the technique. Cavity-enhancement methods for ultrafast nonlinear spectroscopy using frequency combs can provide high-resolution and high sensitivity simultaneously [1].
We will present the results of our simulations of rotationally-resolved 2D spectra of mixtures of volatile organic compounds. We will report the attainable detection limits and selectivity of the technique. In particular, we will compare the performance of CE-2DIR with linear spectroscopy in detection of complex gas mixtures. We will also describe our experimental setup design and our progress towards implementing it in the laboratory.
[1] T.K. Allison, J. Phys. B. (2017) 50, 044004; M.A.R. Reber et al., Optica (2016) 3, 311.