Terahertz compressive imaging with metamaterial spatial light modulators

Imaging at long wavelengths, for example at terahertz and millimetre-wave frequencies(1), is a highly sought-after goal of researchers(2,3) because of the great potential for applications ranging from security screening(4) and skin cancer detection(5) to all-weather navigation(6) and biodetection(7). Here, we design, fabricate and demonstrate active metamaterials that function as real-time tunable, spectrally sensitive spatial masks for terahertz imaging with only a single-pixel detector. A modulation technique permits imaging with negative mask values, which is typically difficult to achieve with intensity-based components. We demonstrate compressive techniques allowing the acquisition of high-frame-rate, high-fidelity images. Our system is all solid-state with no moving parts, yields improved signal-to-noise ratios over standard raster-scanning techniques(8), and uses a source orders of magnitude lower in power than conventional set-ups(9). The demonstrated imaging system establishes a new path for terahertz imaging that is distinct from existing focal-plane-array-based cameras.