Seeing the Invisible: Quantum Spectroscopy and Imaging with Photons We Never Detect

Mid-infrared spectroscopy reveals molecular signatures of proteins and lipids, but conventional detection needs specialised equipment. Quantum correlations between differently coloured photons, including entanglement, offer another approach: a mid-infrared photon interacts with the sample while interference enables its information to be measured with visible or near-infrared light. The speakers explain the underlying principle and the progression from quantum spectroscopy to imaging with undetected photons. They discuss their work at the University of Technology Sydney to turn quantum mid-infrared imaging into compact, practical instrumentation for biological research.