Investigation of wide-aperture plasmonic detectors by a tightly focused terahertz beam

Terahertz response of wide-aperture plasmonic detectors is studied experimentally by using a focused terahertz radiation with frequencies 1.63, 1.89 and 2.55 THz. Two different types of plasmonic detector have been investigated: (i) field-effect transistor (FET) with a grating-gate of large (2×2 mm2) area and (ii) FET with a single gate and ohmic contacts forming a bow-tie antenna. By raster scanning the detector area by using a tightly focused terahertz beam, we studied the contribution of individual parts of the detector to the total detection response and we determined the effective area of the detector structures.