SAMOP 2023 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 58: Quantum Optics with Photons I

Q 58.5: Talk

Thursday, March 9, 2023, 15:30–15:45, F442

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

SU(1,1) interferometers have lately been used for several applications such as achieving super-sensitivity for quantum metrology or enabling spectroscopy and imaging with undetected photons. So far, most of the developed interferometers are based on parametric down-conversion (PDC) from bulk crystals, limiting the brightness of the sources as well as integrability. Furthermore, only spectral or temporal interferograms have been investigated so far.
Here, we demonstrate spectral and temporal interferometry using a SU(1,1) interferometer based on ultra-broadband, non-degenerate dispersion-engineered parametric down-conversion in nonlinear waveguides. These PDC sources exhibit strong frequency correlations and, simultaneously, sub-100 fs photon-photon correlation times. Measuring spectral and temporal interferograms simultaneously allows us to extract the ultra-short biphoton correlation time of our source, a task that has been challenging until now. Knowledge about this quantity is essential for further applications such as entangled two-photon absorption.