Figure 8.

Detection of thermal radiation with a broadband nanometric FET [419]. The main panel shows the setup for the detection of radiation emitted from (Case 1) a ceramic heat source (embedded in a reflector) or (Case2) the human body, here, the palm of a hand. The heater, respectively, the hand, was placed on a $xy$-translation stage for raster-scan imaging. The radiation was guided by two parabolic mirrors and through a mechanical chopper to the detector, where it impinged via a Si substrate lens, attached to the backside of the nanometric FET chip, onto the antenna-embedded transistor. The angles shown are various acceptance angles used for the calculation of the expected noise-equivalent temperature difference (NETD). Inset: Raster-scan image of three fingers of a hand. The measurement was performed at ambient temperature. The black-and-white plot of the 25 × 75-pixel image (white indicating an elevated temperature; black representing room temperature) is superimposed on a photograph of the hand. Figure modified from Ref. [419].