Noise Tolerant Spatio-temporal Ghost Imaging with an Entangled Source

Abstract

We present an imaging system that uses a photon’s position and time-of-flight information to image an object. Since the position of the photons is correlated with their momentum, it is possible to identify the pairs by checking the photons’ timestamp information and localize one of the pair for Spatio-temporal ghost imaging thanks to the momentum conservation of down conversion event. While the timing information of signal (idler) is recorded as reference the idler (signal) is measured after being back-scattered from the object being imaged. With a real-time cross-correlation check of signal and idler photons, the pairs can be identified. The results exhibit multifold quantum enhancement over classical detection in an extremely noisy background. The two-dimensional imaging is performed by mapping the position of signal (idler) photons and register the corresponding coincidence events. The rate of coincidences for a certain position is used to create the image of the object. We also analyze the parameters affecting the image resolution in two dimensions. The method is implemented on imaging of microscopic objects and it was shown that the polarization entanglement is also well preserved during the scattering from the object being imaged.