Electrically Controlled Spatial Light Modulator for Ultrawideband Hyperspectral Terahertz Single-Pixel Imaging

Terahertz (THz) spectroscopic imaging offers significant potential due to its non-destructive penetration and spectral fingerprinting capabilities. However, existing systems face limitations such as high cost, slow acquisition speed, and limited bandwidth, particularly due to the reliance on non-electrical modulators or expensive detector arrays. Here, we present the first electrically controlled spatial light modulator (SLM) for ultrawideband terahertz hyperspectral single-pixel imaging. Our device, based on a non-resonant GaAs Schottky microslit array, provides direct electrical control over both amplitude and phase modulation across a bandwidth of 0.2-1.4 THz. This design offers a compact, low-cost, and highly integrable solution. Utilizing a 100-pixel array operating at ~3.4 kHz, we demonstrated hyperspectral imaging and depth-resolved 3D reconstruction using a single photoconductive detector in both transmission and reflection modes, achieving a frame acquisition time of approximately 9 seconds. This integration of electrically tunable modulation with ultrabroad bandwidth establishes a new paradigm for terahertz imaging, paving the way for applications in biomedical diagnostics, chemical identification, multilayer inspection, and security screening.