Spatial-resolved high-speed THz analog-to-digital convertor comprising phase modulated beam steering architecture

Abstract

We studied and characterized the beam steering effect for THz radiation based on the doubly-corrugated spoofed surface plasmon polariton (DC-SSPP) architecture and analyzed the design of a high-speed THz analog-to-digital converter (ADC). Metal-covered GaAs are used to form both arms of an interferometer, while voltage-controlled, localized carrier concentration provides modulation to the signal propagating phase. Relative phase differences between THz beams in separate arms of the interferometer can give rise to deflected radiation in the far field, which is further converted to a digitized output by a spatially arranged detector array. Applying the beam deflector with a full differential implementation of the input voltage signal and a combination of nonlinear detector arrays with carefully designed gain and saturation power, a 3-bit ADC with > 60 GS/s operation speed and direct digitized readout is demonstrated.