Special Seminar: Quantum-Enhanced Nonlinear Spectroscopy: Probing Materials with Entangled Light

Entangled two-photon absorption spectroscopy has been widely recognized as a potentially powerful tool for revealing novel information about the structure and dynamics of complex molecular systems. However, to date, experimental implementation of this technique has remained elusive, mainly because of the need to perform multiple experiments with two-photon states bearing different temporal correlations. This translates in the lab into the necessity to have at the experimenter’s disposal tens, if not hundreds, of entangled-photon sources. In this talk, I will present an experimentally-feasible scheme that successfully overcomes this limitation. By making use of a single-crystal temperature-controlled entangled-photon source, I will show that the two-photon absorption signal, recorded as a function of the temperature of the nonlinear crystal that generates the photon pairs, and a controllable delay between them, carries all information about the electronic structure of the absorbing medium, which can be revealed by a simple Fourier transformation.