Real-time, continuous-wave terahertz imaging by use of a microbolometer focal-plane array

Area of Science:

• Optics and Photonics
• Imaging Technology
• Terahertz Science

Background:

• Terahertz (THz) imaging offers unique capabilities for non-destructive analysis due to its spectral properties.
• Previous THz imaging systems often required complex setups or were limited by slow acquisition speeds.
• Developing real-time THz imaging is crucial for practical applications such as security screening and quality control.

Purpose of the Study:

• To demonstrate real-time, continuous-wave terahertz imaging at video rates.
• To evaluate the performance of a modified microbolometer camera for THz frequency detection.
• To assess the feasibility of THz imaging for applications like mail screening.

Main Methods:

• Utilized a 10 mW, 2.52 THz far-infrared gas laser as the THz source.
• Employed a 160 x 120 element microbolometer camera, originally designed for 7.5-14 micrometer wavelengths, for THz detection.
• Implemented a transmission-mode setup with no moving parts, achieving image acquisition at 60 frames per second.

Main Results:

• Achieved real-time, continuous-wave terahertz imaging at a video rate of 60 frames/s.
• Demonstrated THz imaging through a standard FedEx envelope, successfully visualizing its contents.
• Estimated a peak signal-to-noise ratio of 13 dB for single-frame video acquisition (16 ms exposure).

Conclusions:

• The developed system enables real-time THz imaging without mechanical components.
• The modified microbolometer camera shows effective sensitivity at THz frequencies.
• This technology presents a feasible solution for real-time mail screening and other rapid inspection tasks.