Dual-comb optical activity spectroscopy for the analysis of vibrational optical activity induced by external magnetic field

Abstract

Optical activity (OA) includes the structural information of (bio) molecular and chemical systems, which is widely utilized in the fields of molecular chirality, pharmaceutics and analytical chemistry. Vibrational circular dichroism (VCD) and optical rotatory dispersion (ORD), spectral measurements of absorption and dispersion induced by OA, are powerful tools and characterize molecular chirality, explore the stereo-specific structure and study the solution-state conformation of biological molecules. In terms of the OA analysis of molecules, detection sensitivity, spectral resolution and acquisition speed are the key indicators that have been pursued. In this paper, we show the unmatched potential of dual-comb spectroscopy (DCS) in magnetic optical activity spectroscopy (MOAS) of gas-phase molecules with the resolution of hundred-MHz level and the high-speed measurement of sub-millisecond level. As a demonstration, we directly achieved the rapid, high-precision and high-resolution MOAS measurement of the nitrogen dioxide υ1 + υ3 band and the nitric oxide overtone band, which can be used to analyze fine structure of molecules. The novel approach of dual-comb optical activity spectroscopy (DC-OAS) paves the way for OA to become a routine approach for rapid characterization of the structural conformations of multiphase systems.