Abstract
An all solid-state metamaterial based terahertz (THz) spatial light modulator (SLM) is presented which uses high mobility 2DEG to manipulate the metamaterial resonant frequency (0.45 THz) leading to terahertz wave modulation. The 2DEG is created by embedding pseudomorphic high-electron mobility transistors in the capacitive gap of each electrical-LC resonator, allowing the charge density to be controlled with very low voltage (1 V) and modulating speeds up to 10 MHz while consuming sub-milliwatt power. We have demonstrated our SLM as a 2 × 2 pixel array operating around 0.45 THz by raster scanning a 6 × 6 image of an occluded metal object behind a thick polystyrene screen using a single-pixel THz imaging setup.
Highlights
In recent years, terahertz (THz) imaging has captured significant interest because of it is potential for a wide range of applications such as bio-detection,[1] security screening,[2] illicit drug detection,[3] and skin cancer detection,[4] to name a few
A 2 × 2 pixel array, demonstrates spatial modulation at very low-voltage (1 V) consuming very low power (
We would like to emphasize that since the imaging is effectively done at a single frequency, a commercial THz imaging system can be designed with a more sensitive single-pixel detector and cheaper source, such as a Schottky diode and diode multipliers, which will be much lower power and cost compared to the cw THz spectrometer used in this work
Summary
Terahertz (THz) imaging has captured significant interest because of it is potential for a wide range of applications such as bio-detection,[1] security screening,[2] illicit drug detection,[3] and skin cancer detection,[4] to name a few. (a) Diagram of the electric-LC (ELC) metamaterial element, with embedded pseudomorphic high-electron mobility transistor (pHEMT) on semi-insulating GaAs substrate, which has been previously demonstrated for high-speed THz modulation.[19] (b) Each single pixel on the terahertz SLM contains a 1 × 1.3 mm[2, 551] element array of metamaterial ELCs. Design and fabrication of the terahertz (THz) SLM. (a) Diagram of the electric-LC (ELC) metamaterial element, with embedded pseudomorphic high-electron mobility transistor (pHEMT) on semi-insulating GaAs substrate, which has been previously demonstrated for high-speed THz modulation.[19] (b) Each single pixel on the terahertz SLM contains a 1 × 1.3 mm[2, 551] element array of metamaterial ELCs These elements are connected together with metal wires and the gates are all connected in a separate metal layer to serve as the source and gate connection of the pHEMTs, respectively. We demonstrate the use of the SLM in a single-pixel THz imaging setup by imaging an occluded object behind a thick polystyrene screen
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