Temporal Discontinuity in Wire Media for Far-Field Subwavelength Imaging

We investigate electromagnetic phenomena in wire media at fast switching between continuous and periodically cut wires. The results show that TEM waves with deeply subwavelength distributions of fields in the transverse plane are effectively converted into propagating waves whose frequencies and propagating directions encode information about the subwavelength field distribution before the switch. Via spectroscopic measurements of the intensity of all these propagating waves (time-refracted and time-reflected ones), one can find the amplitudes and phases of the initial wave package spatial spectrum. We suggest using this effect for $\mathbf{T H z}$ wire media endoscopes, removing the need for tapered multi-wire cables that magnify the image up to minimal values imposed by existing THz detectors.