Terahertz (THz)

In NDT, we use quite a few different wavelengths and frequencies, including X- and gamma radiation, ultrasonic, visual, infrared, ultraviolet and a less often talked about radiation termed terahertz radiation (also known as submillimeter radiation, terahertz waves, tremendously high-frequency T-rays, T-waves, T-light, T-lux or THz).

Terahertz radiation consists of electromagnetic waves within the ITU-designated band of frequencies between 0.3 terahertz to 3 terahertz (THz; 1 THz = 1012 Hz). The wavelengths of radiation in the terahertz band are in the range between 1 mm to 0.1 mm (or 100 μm). Some of the more common uses of terahertz imaging are for airport security checks.

Other commonly used applications are in the pharmaceutical industry, where both the coating and density of tablets are checked. Like sonar or radar, terahertz imaging produces an image by comparing measurements across an array of sensors, hence why it is also being used for accident avoidance in the automotive industry.

Non-destructive contact-free testing terahertz (THz) spectroscopy, and especially THz imaging, has great potential. This can be demonstrated by advances in the development of THz systems, as well as the appearance of commercial products, demonstrating the potential for large-scale market introduction of THz systems. Some of the industrial applications for THz systems comprise the inline monitoring of compounding processes, plastic weld joint inspection, birefringence analysis of fibre-reinforced components, water distribution monitoring in polymers and plants and quality inspection of food products by employing both continuous wave and pulsed THz systems. It is non-ionising and penetrates clothing, paper, cardboard, plastics and composites and has high chemical sensitivity, which can be used for the detection of explosives. From the list of potential uses it is interesting to note what is missing, especially metallic components, but for the non-metallic components that require testing it has the potential to become a useful inspection method.

john.moody@bindt.org

Comments by members

Comment by

Date 30/05/2017

Thank you, John for this valuable information!

Another good example of very promising application is a Security Screening.

THz radiation is safe for screening people and penetrates clothes very well. This makes it an ultimate tool for search of hidden objects on people (e.g. concealed weapons).

Various objects reflect THz radiation so they can be easily seen at THz image. Being harmless to people and functional our device is a good solution for public safety, e. g. for airports and rapid transit systems.

For more promising applications please visit: http://tera-sense.com/applications/

Comment by Alexey Basenko
San Jose, United States

Date 22/05/2017

Thank you, John for this valuable information!

Another good example of very promising application is a Security Screening.

THz radiation is safe for screening people and penetrates clothes very well. This makes it an ultimate tool for search of hidden objects on people (e.g. concealed weapons).

Various objects reflect THz radiation so they can be easily seen at THz image. Being harmless to people and functional our device is a good solution for public safety, e. g. for airports and rapid transit systems.

For more promising applications please visit: http://tera-sense.com/applications/

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