Design and Performance of Extraordinary Low-Cost Compact Terahertz Imaging System Based on Electronic Components and...

Area of Science:

• Physics
• Engineering
• Materials Science

Background:

• Terahertz (THz) imaging offers non-destructive analysis of non-conducting materials.
• Current THz systems face challenges with cost, size, and power consumption.
• Improving the cost-effectiveness of THz imaging is crucial for broader adoption.

Purpose of the Study:

• To design and evaluate an exceptionally low-cost Terahertz (THz) imaging system.
• To assess the performance of commercially available GaAs high-electron-mobility transistors (HEMTs) as sensing elements at room temperature.
• To explore the potential for developing THz imaging systems within a target cost of EUR 100.

Main Methods:

• Utilized an InP Gunn diode as the emitter and paraffin wax for optics.
• Employed commercially available GaAs HEMTs (200 nm gate length) as detectors.
• Evaluated system performance at 94 GHz, measuring spatial resolution and contrast.
• Analyzed signal dependence on gate-to-source voltage to understand detection mechanisms.

Main Results:

• Achieved spatial resolution within the illumination wavelength range (approx. 3 mm).
• Demonstrated a contrast of nearly two orders of magnitude.
• Identified self-resistive mixing and antenna effects as key contributions to the detected signal.
• Determined a cross-sectional responsivity of 27 V/W and noise-equivalent power of 510 pW/Hz at 94 GHz.

Conclusions:

• An affordable THz imaging system was successfully designed and demonstrated.
• Commercially available HEMTs can function effectively as THz detectors at room temperature.
• Further development could lead to ultra-low-cost THz imaging solutions suitable for widespread applications.