Single-chip nanophotonic near-field imager

Near-field imaging in the microwave regime has many applications from radar to through-the-wall imaging and cancer cell detection. Currently, practical near-field imagers are implemented as benchtop systems and therefore are bulky, expensive, and typically susceptible to electromagnetic interference. Here we introduce and demonstrate the first single-chip nanophotonic near-field imager, where the impinging microwave signals are upconverted to the optical domain and optically delayed and processed to form the near-field image of the target object. The 121-element imager, which is integrated on a silicon chip, is capable of simultaneous processing of ultra-wideband microwave signals and achieves 4.8° spatial resolution for near-field imaging with orders of magnitude smaller size than the benchtop implementations and a fraction of the power consumption.