Terahertz subwavelength single-pixel video based on computational imaging

We report a high-speed terahertz (THz) single-pixel video imaging system integrating comprehensive theoretical modeling and experimental validation. Employing Hadamard and Fourier encoding schemes with a Si₃N₄/Si wafer modulator driven by a continuous-wave laser, the system achieves a modulation bandwidth of 6 kHz, enabling subwavelength resolution of 1 mm and signal-to-noise ratios exceeding 20. For 32 × 32 pixel images, the Fourier method requires only 200 measurements to attain a peak SNR above 25 dB and a structural similarity index greater than 0.7, enabling video-rate THz imaging. Experimental results demonstrate effective real-time detection of metal targets embedded within paper. Compared with existing methods, the proposed system significantly improves imaging speed, quality, and computational efficiency. This work advances terahertz single-pixel imaging toward practical applications, including remote sensing, nondestructive evaluation, and microscopy. Future research will focus on optimizing sampling and reconstruction to further enhance frame rates and target recognition accuracy.