The resonant tunability, enhancement, and damping of plasma waves in the two-dimensional electron gas plasmonic crystals at terahertz frequencies

The ability to manipulate plasma waves in the two-dimensional-(2D)-electron-gas based plasmonic crystals is investigated in this work. It is demonstrated that the plasmon resonance of 2D plasmonic crystal can be tuned easily at terahertz frequency due to the wavevector quantization induced by the size effect. After calculating self-consistently by taking into account several potential mechanisms for the resonant damping of plasma waves, it can be concluded that the plasmon-plasmon scattering plays the dominant role. Based on the calculations, we can predict the scattering or inter-excitation among the oblique plasmons in the 2D crystal. The results can be extended to study 2D-electron-gas plasmonic waveguides, terahertz modulators, and detectors with electrostatic gating.