Quantum undetected optical projection tomography

Quantum imaging with undetected photons (QIUP) is an emerging technique that decouples the processes of illuminating an object and projecting its image. The properties of the illuminating and detected light can thus be simultaneously optimised for both contrast on a sample and sensitivity on a camera. Here, we combine QIUP with computed tomography to enable three-dimensional (3D) infrared imaging. The image data is registered with a standard silicon camera at a wavelength of 810 nm, but the extracted 3D images map the sample's absorption at a wavelength of 1550 nm, well beyond the camera's sensitivity. Quantum Undetected Optical Projection Tomography (QUOPT) enables label-free volumetric sensing at difficult to detect wavelengths, such as those that allow molecular imaging contrast, or those within the infrared biological transmission windows.