Mitigating Electrode-Induced Polarization Artifacts in Miniaturized Terahertz Detectors via a Ring-Shaped Electrode Design

Terahertz (THz) polarization detection provides critical insights into material properties but faces a fundamental constraint upon miniaturization: subwavelength metallic electrodes induce strong field localization, convoluting the intrinsic device response with electrode-induced artifacts. Here, we overcome this limitation with a ring-shaped electrode architecture that suppresses field perturbations across 2.0–5.0 THz. The resonant frequency can be detuned from the target operation frequency by adjusting its inner and outer radii, while the smooth geometry minimizes the lightning-rod effect. Numerical simulations reveal an 8.48 ×reduction in local field strength compared with conventional rod-shaped electrodes. Consistent with this, experimental measurements on graphene-based detectors exhibit a 6.95 ×decrease in photocurrent for the ring-shaped electrode relative to the rod-shaped configurations. Moreover, the ring geometry reduces the linear polarization ratio of the photocurrent from >3 to <1.4, confirming its effectiveness in mitigating electrode-induced polarization anisotropy. Beyond single-frequency experimental validation, multiphysics simulations across 2.0–5.0 THz show that detectors with ring-shaped electrodes maintain consistently low photovoltage over the entire range, suggesting broadband suppression capability. Our design decouples the detection response from electrode-induced artifacts, enabling compact THz detectors that preserve intrinsic signal fidelity for high-quality polarization-resolved imaging and diagnostics.