Far-Infrared Spectrum Analysis Using Plasmon Modes in a Quantum-Well Transistor

Excitation of resonant plasmon modes by far-infrared (FIR) radiation in a quantum-well transistor is used to analyze the spectral content of FIR illumination at frequencies between 0.58 and 0.99 THz. A split grating gate design that allows localized pinch-off of the transistor channel greatly enhances FIR response and allows completely electrical tuning of the plasmon resonance, enabling broadband FIR spectrum analysis without moving parts. A voltage ramp applied to the gate can generate a spectrum at video rate