Erlangen 2022 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 65: Quantum Information (Miscellaneous)

Q 65.1: Talk

Friday, March 18, 2022, 10:30–10:45, Q-H12

Bi-photon correlation time measurement with a two-colour broadband SU(1,1) interferometer — •Franz Roeder, Matteo Santandrea, René Pollmann, Michael Stefszky, Victor Quiring, Raimund Ricken, Christof Eigner, Benjamin Brecht, and Christine Silberhorn — Paderborn University, Department of Physics, Integrated Quantum Optics, Institute for Photonic Quantum Systems (PhoQS), Warburger Straße 100, 33098 Paderborn, Germany

SU(1,1) interferometers have been investigated intensively lately for applications such as spectroscopy or imaging with undetected photons. These interferometers are mostly utilising engineered broadband non-degenerate PDC sources as active elements to achieve broad spectral coverage. Being pumped with a narrow bandwidth CW laser, these PDC sources exhibit strong frequency correlations and simultaneous correlation times between the photons down to below 100 fs. In general, such short correlation times are hard to measure. Nevertheless, knowledge about this quantity is essential for further applications such as entangled two-photon absorption.

In this contribution, we show that the fringing pattern, measured in terms of single photon numbers and coincidence counts, of a SU(1,1) interferometer is directly connected to the correlation time.

We will present measurements from an interferometer consisting of a broadband integrated Type-II PDC source operating at wavelengths of 830 nm and 1370 nm. We are able to deduce the correlation time of the bi-photons within the interferometer and discuss its significance for applications.