Enhancing Circular Dichroism Signals with Vector Beams

Lyuzhou Ye, Longqing Yang, Xiao Zheng, and Shaul Mukamel

Phys. Rev. Lett. 126, 123001 – Published 26 March 2021

Abstract

Circular dichroism (CD) is broadly employed for distinguishing molecular chiralities. However, its practical application is often limited by the weak magnitude of chiral signal. We propose to use azimuthally and radially polarized vector beams to probe CD spectra. By taking advantage of the strong longitudinal components of the vector beams, the transmitted light can be detected in the radial direction. The resulting CD signal is several orders of magnitude stronger than conventional CD signal with plane waves. Quantitative analysis and numerical simulations show that the enhancement factor is independent of molecular properties and can be increased by decreasing the path length of the sample cuvette and the interaction cross section between the light beam and molecular sample. The proposed novel CD spectroscopy is feasible with the current optical technology.

Received 5 January 2021
Accepted 24 February 2021

DOI:https://doi.org/10.1103/PhysRevLett.126.123001

Physics Subject Headings (PhySH)

Chirality Laser applications Laser spectroscopy Molecular spectra Spatial profiles of optical beams

Atomic, Molecular & Optical

Authors & Affiliations

Lyuzhou Ye ¹, Longqing Yang¹, Xiao Zheng ^1,2,*, and Shaul Mukamel ³

¹Hefei National Laboratory for Physical Sciences at the Microscale & Synergetic Innovation Center of Quantum Information and Quantum Physics and CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui 230026, China
²Department of Chemical Physics and Key Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education Institutes, University of Science and Technology of China, Hefei, Anhui 230026, China
³Department of Chemistry and Department of Physics and Astronomy, University of California, Irvine, California 92697, USA