The overcoming diffraction restrictions to achieve superhigh NEP and sub-diffraction resolution in terahertz frequency range receiving systems

It was noticed that in receiving systems of terahertz frequency range, as transitional one between microwave and infrared ranges, the transition from lumped receiving elements to distributed ones (areal or voluminal) as well as the transition from waveguide methods of incident radiation beam matching with receiving elements to optical methods take place. Frequently one and other matching methods are used in combination. Main reason of this is considerable diffraction restrictions in this frequency range in comparison with optical range resulting by-turn in the restriction of sensitivity to incident signal radiation as well as in the restriction of observing image spatial resolution.