Switchable plasmonic terahertz sources and detectors for high-throughput imaging

Abstract

Terahertz time-domain spectroscopy (THz-TDS) enables broadband, time-resolved imaging for applications ranging from non-destructive inspection to biomedical diagnostics, but conventional imaging systems relying on single pixel devices with mechanical scanning are inherently slow and poorly scalable. High-throughput THz imaging requires focal-plane arrays (FPAs) of either sources or detectors with efficient pixel-level addressing. In this work, we present a switchable plasmonic THz pixel architecture based on the monolithic integration of a GaAs MESFET with a plasmonic photoconductive THz detector. The MESFET functions as a high ON/OFF ratio electronic switch that suppresses signal transmission in the OFF state while preserving bandwidth and signal-to-noise ratio in the ON state. Fabricated prototypes demonstrate ON/OFF resistance ratios exceeding 10⁴, corresponding to THz power dynamic ranges greater than 80 dB when integrated with 250 µm × 250 µm detector pixels. The same platform can be extended to implement switchable plasmonic THz sources, enabling scalable high-throughput imaging systems.