title: Quantum optical rotatory dispersion.
abstract: The phenomenon of molecular optical activity manifests itself as the rotation of the plane of linear polarization when light passes through chiral media. Measurements of optical activity and its wavelength dependence, that is, optical rotatory dispersion, can reveal information about intricate properties of molecules, such as the three-dimensional arrangement of atoms comprising a molecule. Given a limited probe power, quantum metrology offers the possibility of outperforming classical measurements. This has particular appeal when samples may be damaged by high power, which is a potential concern for chiroptical studies. We present the first experiment in which multiwavelength polarization-entangled photon pairs are used to measure the optical activity and optical rotatory dispersion exhibited by a solution of chiral molecules. Our work paves the way for quantum-enhanced measurements of chirality, with potential applications in chemistry, biology, materials science, and the pharmaceutical industry. The scheme that we use for probing wavelength dependence not only allows one to surpass the information extracted per photon in a classical measurement but also can be used for more general differential measurements.
authors.affiliation: Vienna Center for Quantum Science and Technology, Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria.; Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Boltzmanngasse 3, A-1090 Vienna, Austria.; Department of Physics and Astronomy, Centre for Engineered Quantum Systems, Macquarie University, Sydney, New South Wales 2109, Australia.
authors.forename: Nora
authors.identifier: 0000-0002-4048-2185
authors.initials: N
authors.lastname: Tischler
authors.affiliation: Vienna Center for Quantum Science and Technology, Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria.; Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Boltzmanngasse 3, A-1090 Vienna, Austria.
authors.forename: Mario
authors.initials: M
authors.lastname: Krenn
authors.affiliation: Vienna Center for Quantum Science and Technology, Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria.; Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Boltzmanngasse 3, A-1090 Vienna, Austria.
authors.forename: Robert
authors.initials: R
authors.lastname: Fickler
authors.affiliation: Department of Physics and Astronomy, Centre for Engineered Quantum Systems, Macquarie University, Sydney, New South Wales 2109, Australia.
authors.forename: Xavier
authors.identifier: 0000-0001-8026-2016
authors.initials: X
authors.lastname: Vidal
authors.affiliation: Vienna Center for Quantum Science and Technology, Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria.; Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Boltzmanngasse 3, A-1090 Vienna, Austria.
authors.forename: Anton
authors.initials: A
authors.lastname: Zeilinger
authors.affiliation: Department of Physics and Astronomy, Centre for Engineered Quantum Systems, Macquarie University, Sydney, New South Wales 2109, Australia.
authors.forename: Gabriel
authors.identifier: 0000-0002-7905-4938
authors.initials: G
authors.lastname: Molina-Terriza
keywords: chirality; entangled photons; optical activity; optical rotatory dispersion; quantum metrology