Patent ID: 11187518

Abstract:
A method of determining a displacement comprises: generating an interferometric superoscillatory field from coherent electromagnetic radiation, the interferometric superoscillatory field comprising an interference pattern between a reference field and a superoscillatory field; detecting with a detector a first set of intensity distributions of the interferometric superoscillatory field, each intensity distribution from a different polarisation state of the electromagnetic radiation; detecting with the detector a second set of intensity distributions of the interferometric superoscillatory field, each intensity distribution from the same polarisation states of the electromagnetic radiation as the first set of intensity distributions; extracting a first local wavevector distribution from the first set of intensity distributions and a second local wavevector distribution from the second set of intensity distributions; comparing the first local wavevector distribution and the second local wavevector distribution to identify any change in position of one or more features in the local wavevector distributions; and ascertaining that a lateral displacement has occurred between the interferometric superoscillatory field and the detector if a change in position is identified.