Monolithic Multiparameter Terahertz Nano/Microdetector Based on Plasmon Polariton Atomic Cavity

Abstract Terahertz (THz) signals are crucial for ultrawideband communication and high‐resolution radar, demanding miniaturized detectors that can simultaneously measure multiple parameters such as intensity, frequency, polarization, and phase. Traditional detectors fail to meet these needs. To address this, we introduce a plasmon polariton atomic cavity (PPAC) detector based on monolayer graphene, offering a multifunctional, monolithic, and miniaturized solution. With a footprint only one‐tenth the size of the incoming wavelength, the PPAC achieves benchmark performance in intensity‐, frequency‐, and polarization‐sensitive detection. Operating at room temperature across 0.22–4.24 THz, it delivers sub‐diffraction detection resolution and high‐speed operation. Furthermore, we demonstrate its application in free‐space THz polarization‐coded communication and stealth imaging for physical property analysis. The unique design of PPAC enables strong absorption with weak signal detection, within a structure just 10 −5 times the excitation wavelength in thickness, an accomplishment beyond current technologies. By simultaneously resolving intensity, frequency, and polarization, this detector can replace multiple single‐function devices, providing a compact and efficient solution for next‐generation ultrawideband communication and high‐resolution radar systems.