Electromagnetic superscattering and invisible gateways

Illusion optical devices based on transformation optics show phenomena that are rare in nature, for example, invisibility cloaking, superscattering, and invisible gateways. The folded-geometry transformation offers theoretical guidance to the design of the superscattering effect, which subverts people's traditional perception that the scattering cross-section is smaller than the geometrical cross-section of the object. In superscattering, the cross-section of an object can be much larger than its geometrical cross-section, which can be utilized to realize the dream of going through a wall. In this paper, after some historical introduction, the realization of invisible gateways based on superscattering is introduced in detail; the experimental demonstration of invisible gateways in free space may provide new ideas for the design of illusion devices for the future.