Mid-infrared Imaging with Undetected Light using Nonlinear Metasurfaces

Our team is part of the UK Quantum Imaging Hub investigating the use of quantum correlated light sources for infrared imaging. Here we are applying a method of imaging with undetected photons*, where an image is formed from photons that haven't interacted with the object in view at all! Apart from the intriguing fundamental aspect of this research, it has the practical advantage that high performance detectors in the visible, can be used to form images with other scientifically important, but technologically challenging, spectral regions - especially the mid infrared, which hosts the fingerprints of molecular vibrations.

The project involves developing nonlinear optics techniques to produce photon pairs bridging the visible and mid infrared (3-12 um wavelength), where vibrational absorption bands allow the chemistry of the object to be inferred. This can be achieved with certain conventional nonlinear materials, but we are also exploring artificial nonlinear materials, known as nonlinear metasurface, which are structured at the nanoscale. The project will work closely with the National Physical Laboratory (NPL) to characterise metasurfaces in the mid infrared. The results will be combined from other IR imaging methods in the group, including sub-wavelength s-SNOM images of cells and graphene devices, and our "Digistain" IR based cancer detection technology.

* Lemos et al "Quantum imaging with undetected photons" doi:10.1038/nature13586