Figure 1
(a) Cutaway diagram of the experiment configuration. The sample sits inside a Styrofoam cup holding liquid nitrogen. The gold slide creates a shadow allowing a portion of the sample to be illuminated by the laser. (b) Half-illumination geometry for a single ring and (c) a four-element linear array. The x-axis points toward the in-plane antenna. (d) Notional diagram of the GHz-radiation measurement set-up25. Two antennas detect radiation from the sample. One is positioned in the plane of the ring, the other below the ring. Polarized radiation due to different laser illumination locations is indicated below the ring. (Note: diagrams are not drawn to scale).
