Quantum Image Distillation with Undetected Photon Beam

Imaging via nonlinear interferometers make use of induced coherence and take advantage of photon pair correlations to image an object without detecting the photons that illuminate the object [1]. The object's information is transferred from the photon that illuminates the object to the interference pattern of its partner photon, which is detected [2]. Spontaneous parametric down conversion allows to utilize photon pairs with large spectral separation. This fact becomes relevant if we need to image at wavelengths with detection constraints, e.g., mid-infrared, hyperspectral, or terahertz wavelengths [3], [4].