SAMOP 2021 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 16: Quantum Optics
Q 16.1: Poster
Donnerstag, 23. September 2021, 16:30–18:30, P
Incoherent seeding of a nonlinear interferometer — •Joshua Hennig1,2, Björn Haase1,2, Mirco Kutas1,2, Georg von Freymann1,2, and Daniel Molter1 — 1Center for Materials Characterization and Testing, Fraunhofer ITWM, Kaiserslautern, Germany — 2Department of Physics and Research Center OPTIMAS, Technische Universität Kaiserslautern (TUK), Germany
Quantum sensing and imaging with undetected photons based on nonlinear interferometry has been demonstrated in various spectral regions in the past few years. Due to their low photon energy in the terahertz frequency range thermal photons contribute to the signal at room temperature. In order to investigate the effect of such incoherent photons on a nonlinear interferometer, we use an incoherent seed on a Mach-Zehnder approach based on [1]. Here, spontaneous parametric down conversion of two nonlinear crystals pumped by a 532 nm laser leads to correlated pairs of signal and idler photons at wavelengths of 810 nm and 1550 nm, respectively. While the idler photons interact with an object, only the signal photons, which then carry the object’s information, are detected with a scientific CMOS camera. That way, the information can be transferred from one wavelength to another. By seeding the idler of this experiment incoherently at 1550 nm, we find that the detected count rate can be increased by at least an order of magnitude while the visibility of the interference reaches up to 90% compared to about 70% without seeding. This can be beneficial in applications with low count rates or where detectors are sparse.
[1] Lemos et al., Nature 512(7515), 409-412 (2014)