SAMOP 2021 – scientific programme
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MO: Fachverband Molekülphysik
MO 3: Chirality
MO 3.7: Talk
Tuesday, September 21, 2021, 12:30–12:45, H3
High-Sensitivity and Rapid Measurements of Broadband Optical Activity with Interferometric Fourier-Transform Balanced Detection — •Soumen Ghosh1, Georg Herink2, Antonio Perri1,3, Fabrizio Preda1,3, Cristian Manzoni4, Dario Polli1,3,4, and Giulio Cerullo1,3,4 — 1Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy — 2Experimental Physics VIII, University of Bayreuth, D-95447 Bayreuth, Germany — 3NIREOS S.R.L., Via G. Durando 39, 20158 Milano, Italy — 4Istituto di Fotonica e Nanotecnologie (IFN) - CNR, Piazza Leonardo da Vinci 32, I-20133 Milano, Italy
We present a novel configuration for high-sensitivity and rapid measurement of broadband CD and ORD spectra spanning the visible and near-infrared. The setup utilizes a linearly polarized light that creates an orthogonally polarized weak chiral free-induction-decay field, along with a phase-locked achiral transmitted signal which serves as the local oscillator for heterodyne amplification. By scanning the delay between the two fields with a birefringent common-path interferometer and recording their interferogram with a balanced detector, broadband CD and ORD spectra are retrieved simultaneously with a Fourier transform. Using an incoherent thermal light source, we achieve state-of-the-art sensitivity for CD and ORD across a broad wavelength range with a measurement time of just a few seconds. The setup allows high-sensitivity measurement of glucose concentration and real-time monitoring of fast asymmetric chemical reactions. The setup can further be extended for broadband transient optical activity measurements.