Visualisation of the electric fields in the core of a waveguide

The technique presented exploits the absorptive capacity of a plate and especially its ability to convert electromagnetic energy integrally into a thermal form, so that low power levels of irradiation suffice to produce heating which can be detected by infrared thermography (less than 1 W). The infrared camera could be positioned directly opposite the output of the open waveguide covered by the plate. The total absence of reflectivity ensures that the presence of the plate induces no interference. The technique is of exemplary simplicity since it can be used on industrial applicators without an anechoic chamber or other special environment.