Probing Plasmon Resonances in AlGaN/GaN Heterostructures with 300 K black-body radiation

Our study reveals the efficient modulation of room-temperature thermal radiation by terahertz plasmons in AlGaN/GaN grating-gate structures. We demonstrate close alignment between resulting spectra and plasmon absorption measurements using high-power external sources. Despite weak reflected radiation intensity for typical plasmonic samples, precise measurements require gate voltage plasmon modulation and lock-in detection techniques, with caution against artifacts. Modulation of drain voltage also influences reflected thermal radiation by plasmons. These findings are crucial for advancing research on resonant plasmon-based terahertz sources, navigating the interplay between electrically excited terahertz emission and reflected background radiation.