Quantum 2025 – scientific programme
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THU: Thursday Contributed Sessions
THU 13: Poster Session: Applications
THU 13.75: Poster
Thursday, September 11, 2025, 16:30–18:30, ZHG Foyer 1. OG
Fast Mid-IR Spectroscopy with Cavity Enhanced SPDC source — •Atta ur Rehman Sherwani1, Helen Chrzanowski1, Felix Mann1, Emma Pearce4, Fabian Wendt3, and Sven Ramelow1,2 — 1Faculty of Mathematics and Natural Sciences, Humböldt-Universität zu Berlin, Germany — 2Ferdinand-Braun-Institut GmbH, Leibniz-Institut für Höchstfrequenztechnik, Berlin, Germany — 3Fraunhofer-Institut für Lasertechnik ILT, Aachen, Germany — 4School of Physics and Astronomy, University of Glasgow, Scotland
Microplastics, typically between 1 and 10 um in size, are persistent pollutants that pose significant environmental and health risks due to their resistance to degradation and biological accumulation. Conventional detection techniques, such as Fourier-Transform Infrared (FTIR) and Raman spectroscopy, analyse vibrational absorption spectra but face limitations when identifying micro-scale particles, including high costs, slow acquisition, and complex sample preparation. This work explores an alternative way to mid-infrared spectroscopy by using undetected photons generated via spontaneous parametric down-conversion (SPDC) in a monolithic cavity of ppKTP. One photon probes the sample in the mid-infrared, while its entangled partner is detected in the visible range using silicon detectors, eliminating the need for expensive mid-infrared sensors. The system is designed to target specific absorption bands characteristic of plastics. This technique holds strong potential as a compact, cost-effective, and rapid alternative for microplastic detection in environmental and biological monitoring applications.
Keywords: SPDC; non- linear interferometer; Spectroscopy; Micro-Plastics