Observation Of Evanescent-Wave Filtering In Super-Resolved Thz Images

According to rigorous diffraction theory, monochromatic electromagnetic waves reflected from a material surface form a mixture of propagating and evanescent waves. During propagation, light fields suffer a progressive spatial filtering that depends exponentially on the size of the subwavelength image detail, a peculiar multiscale distortion in the image that spans the near-field of the sources, occurs in vacuum and with no dissipation, and has never been reported before.