arXiv subjects

Nathan Gemmell

Publications and source records attributed to Nathan Gemmell.

3 recordsLinked to original sources

arXiv2026

Wide-field mid- to long-wave infrared imaging with undetected photons

Quantum imaging with undetected photons (QIUP) allows an object to be probed at mid-infrared frequencies by only measuring interference in the visible range, thus leveraging silicon camera technology. We show that non-collinear phase-matching in a silver thiogallate (AgGaS$_2$) crystal enables wide-field QIUP in the wavelength range of 6-10 $\mu$m (1670-1000 cm$^{-1}$). A combination of coherent detection and infrared photons being ``undetected'' enables imaging at ${\sim}$100 times better than the background-limited infrared photodetection (BLIP) limit. At 8 $\mu$m, our images have over 8000 $\pm$ 100 resolvable elements with a 297 $\pm$ 5 $\mu$m resolution, and 10 s acquisition time. Our results pave the way to fast, background-noise-free, room-temperature, spectrally-selective mid-infrared imaging.

quant-ph↗

arXiv2025

Phase-Matching-Free Sensing with Undetected Light Using a Nonlinear Thin-Film Metasurface

In this article, we report classical sensing with undetected light at a wavelength of 1500 nm, detected on a silicon camera at 580 nm, using four-wave mixing from a plasmonic metasurface. The bidirectional nonlinear scattering due to inherent reflections from such thin nonlinear materials modifies their operation within a nonlinear interferometer. The theoretical model for visibility accounting for such bidirectionality as well as pulsed illumination accurately predicts visibility in the system as a function of transmission in the near-infrared seed (idler) arm. Spectrally resolving the visible signal emission evaluates the total dispersion within the interferometer, highlighting the prospect of ultrafast sensing with undetected photons.

physics.optics↗

arXiv2023

Eliminating Thermal IR Background Noise by Imaging with Undetected Photons

Spectroscopy and imaging in the mid-infrared (2.5 $μ$m $\sim$ $λ$ $\sim$ 25 $μ$m) is bedevilled by the presence of a strong 300 K thermal background at room temperature that makes IR detectors decades noisier than can be readily achieved in the visible. The technique of "imaging with undetected photons" (IUP) exploits the quantum correlations between entangled photon pairs to transfer image information from one spectral region to another, and here we show that it does so in a way that is immune to the thermal background. This means that IUP can be used to perform high speed photon counting measurements across the mid-IR, using uncooled visible detectors that are many times cheaper, faster, and more sensitive than their IR counterparts.

quant-ph↗