Effect of current on terahertz plasmons in AlGaN/GaN heterostructures

Terahertz transmittance spectra of plasmonic crystals based on two-dimensional electron gas in AlGaN/GaN heterostructures were studied in grating-gate and gateless plasmonic crystals as a function of lateral bias. The decrease in the plasmon resonance frequencies (redshift) with the increase in the lateral current was observed for both types of structures. We show that the change of the electron concentration profile and Joule heating are the main phenomena responsible for the shift of the plasma resonant frequency. These results are important for designing plasmonic resonance-based filters, detectors, and emitters operating under voltage bias conditions.