A method and a sensing device are provided. The sensing device may include: a thermal antenna that includes a resistive material and has a cross section that has dimensions that are of an order of a micron or of a sub-micron. The thermal antenna may receive electromagnetic radiation and directly convert it to heat. The sensing device may also include a supporting element, a thermal sensor arranged to generate detection signals responsive to a temperature of a sensed area of the thermal sensor, a holding element that may support and thermally isolate the thermal antenna and the thermal sensor and thermally isolate, and a readout circuit that may process the detection signals to provide information about the electromagnetic radiation that is directly converted to heat by the thermal antenna. The thermal antenna and the thermal sensor are spatially separated from the supporting element.