One of astronomers’ tricks for observing distant objects is intensity interferometry, which involves comparing the intensity fluctuations recorded at two separate telescopes. Researchers have now applied this technique to the imaging of remote objects on Earth [1]. They developed a system that uses multiple laser beams to illuminate a distant target and uses a pair of small telescopes to collect the reflected light. The team demonstrated that this intensity interferometer can image millimeter-wide letters at a distance of 1.36 km, a 14-fold improvement in spatial resolution compared with a single telescope.
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