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We present measurements on the spatial-response profiles of nanometer-scale thin-film Ni-NiO-Ni diodes integrated with infrared dipole and bow-tie antennas. Antennas are usually tested for their angular response using collimated radiation. However, in this study, focused radiation with a wavelength of 10.6 micrometer is scanned across the receiving area of the detector. This permits determination of the effective collection area of an individual infrared antenna. The width of the collection area parallel to the antenna axis is shown to scale with the physical length of the antenna. The determination of the effective collection area permits a characterization of the fringe fields surrounding the antenna and can be used to investigate the cross talk between adjacent antennas. It allows calculation on the power collected by an infrared antenna for a given irradiance of the illuminating beam. The spatial response also gives insight into the current-wave modes propagating on the antenna. Fast infrared detectors have dimensions considerably smaller than the wavelength of the incident radiation. Their performance is enhanced with the aid of wire or planar antennas having dimensions comparable with the wavelength. The efficiency of infrared lithographic antennas for detection at wavelengths near 10 micrometer was demonstrated with various types of detectors, including thin film metal-oxide-metal diodes (MOM or MIM) and Nb microbolometers. To investigate the mechanism of infrared antennas, we determine the spatial response of various dipole and bow-tie antennas at 10.6 micrometer wavelength. For this purpose, we scan tightly focused radiation at normal incidence across the receiving area of the detector in two orthogonal directions. The effective receiving area is a relevant parameter for infrared antennas. It first permits a radiometric characterization of the detector based on received power for a given incident irradiance. It also defines the spacing of individual detectors required for construction of an area receiver, and in a two-dimensional array allows calculation of cross-talk level between adjacent devices. The spatial response of infrared antennas on a substrate also contributes to the understanding of the resonant modes propagating on the structure.
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