Abstract: In order to perform high-accuracy authentication of a forgery prevention medium having a forgery prevention structure, the forgery prevention structure provided in or on the medium for performing authentication of the medium is formed so as to include a mixed area with a plurality of kinds of resonator structures each of which resonates with a terahertz electromagnetic wave having a different polarization direction.

Abstract: In order to perform high-accuracy authentication of a forgery prevention medium having a forgery prevention structure, a forgery prevention structure provided in or on a medium for performing authentication of the medium includes: an anisotropic resonator that resonates in response to being irradiated with a first terahertz electromagnetic wave at a first frequency, a transmissivity of the first terahertz electromagnetic wave changes with a polarization direction of the first terahertz electromagnetic wave, and an isotropic resonator that resonates in response to be irradiated with a second terahertz electromagnetic wave at a second frequency, a transmissivity of the second terahertz electromagnetic wave does not change with a polarization direction of the second terahertz electromagnetic wave.

Abstract: An electromagnetic wave detection apparatus easily detects characteristics of an object with respect to terahertz electromagnetic waves having different polarization directions. The apparatus includes: a first transceiver that transmits a first terahertz electromagnetic wave having a first polarization direction to a medium; a second transceiver that transmits a second terahertz electromagnetic wave having a second polarization direction different from the first polarization direction to the medium; and circuitry that detects a characteristic of the medium from portions of the first terahertz electromagnetic wave and the second terahertz electromagnetic wave that pass through the medium and are received by the first transceiver and the second transceiver respectively.