Enhancement of contrast and spatial resolution in confocal coherent terahertz imaging system

The effect of enhancement of image contrast and spatial resolution without the loss of the spectral composition of the radiation under investigation has been experimentally demonstrated for a terahertz far-field imaging system. The result has been obtained by using a confocal aperture placed in the intermediate-focus region of the optical system. The result is a fundamental advance towards the achievement of subwavelength resolution and the contrast of microscopy systems in the terahertz spectral range.