Real-time continuous-wave terahertz line scanner based on a compact 1 × 240 InGaAs Schottky barrier diode array...

Area of Science:

• Physics
• Engineering
• Materials Science

Background:

• Terahertz (THz) imaging offers non-ionizing radiation for material analysis.
• Real-time imaging systems are crucial for practical applications like quality control and security screening.
• Schottky barrier diode (SBD) array detectors provide sensitive detection in the THz range.

Purpose of the Study:

• To demonstrate a real-time continuous-wave terahertz (THz) line-scanned imaging system.
• To evaluate the system's capability for detecting foreign substances with high spatial resolution.
• To improve the signal-to-noise ratio of the detector through enhanced source beam quality.

Main Methods:

• Utilized a 1 × 240 InGaAs Schottky barrier diode (SBD) array detector.
• Employed a 200-GHz gyrotron as the THz source.
• Integrated a conveyor system and optical components including a high-density polyethylene lens, metal mirror, and THz wire-grid polarizer.
• Achieved a scan velocity of 25 cm/s and a pixel size of 0.5 × 0.5 mm².

Main Results:

• Demonstrated clear detection of foreign substances, such as a paper clip hidden under a cracker.
• Achieved a spatial resolution of approximately 1 mm.
• Showcased real-time continuous-wave THz line-scanned imaging with a scan line length of 12 cm.
• Improved the signal-to-noise ratio of the SBD array detector by enhancing source beam quality using a THz polarizer.

Conclusions:

• The developed THz line-scanning system enables effective real-time imaging and detection of concealed foreign materials.
• The integration of an InGaAs SBD array detector and optimized optical components leads to high-resolution imaging.
• This technology holds promise for various applications requiring non-destructive inspection and material characterization.