Ultra-Spectrally Selective Terahertz Pyroelectric Detector

Technology #34367

Key Points

  • Handheld, portable device that intercepts electromagnetic radiation in the terahertz frequency range
  • Replaces the need for liquid helium-cooled bolometers with external spectrometers
  • Safely detects dangerous narcotics and compounds such as fentanyl

Abstract

Researchers at the University of Central Florida have invented a device that can intercept electromagnetic radiation in the terahertz (THz) frequency range more effectively without the costly components that other detection methods require. A key aspect of THz radiation is its ability to penetrate a wide range of materials without damaging target objects. Example materials include plastics, foams, clothing, wood, masonry and ceramics. Thus, the invention is applicable in many areas, such as security screening for illicit substances (like the narcotic, fentanyl), counterfeit currency, and hazardous items, including explosives. THz waves penetrate deeper than infrared (IR) waves, provide better resolution than radio and microwaves, and exhibit lower scattering than IR and visible light.

Devices used for electromagnetic radiation in the mid- and long-wave infrared spectral regions are not designed for detecting THz wavelengths and cannot be easily adapted. Other alternatives require multiple optical components (like bolometers that require liquid helium cooling) to achieve similar parameters with lower effectiveness. As a solution, the UCF device is specifically designed to detect THz wavelengths and eliminates the need for alternative methods and devices. Additionally, the invention keeps personnel safe by being contact-free and accurately provides results in seconds. It is simple to operate and interpret, requiring only minimal training.

Technical Details

The UCF invention comprises a pyroelectric detection device and methods for using it to receive and identify electromagnetic radiation in the THz frequency range (0.1 ‐ 5) with ultra‐narrow channel widths (0.06 THz) FWHM. Depending on its configuration, the device may either act as a large area resonator to collect weak/diffuse signals or as a constituent of an array able to take pictures within the spectrum for which it is sensitive. The device can include a pyroelectric element for generating reflectance spectra.

In one configuration, the UCF device is a portable handheld unit. The unit may include a broadband mercury source, stereoscopic detection scheme for localization, and a visible camera for overlaying images, such as an active pixel sensor. The element may consist of an aluminum nitride film and conductive layers of chromium and gold. One conductive layer contains a periodic array of plasmonic absorbers that simultaneously provide capacitive and inductive coupling of electromagnetic radiation. A non-contact THz reflectance spectroscope provides the means for identifying targets of interest. The spectroscope comprises a light source and a camera to emit far-infrared wavelength electromagnetic radiation onto a target. Measurement circuitry connected to the conductive layers measures electrical signals from the reflectance spectra. Analysis circuitry then compares the reflectance spectra to known spectra to identify various objects or substances.

Partnering Opportunity

The research team is looking for partners to develop the technology further for commercialization.

Stage of Development

Prototype available.

Benefit

Replaces the need for liquid helium cooled bolometers with external spectrometers

Market Application

  • Drug screening by police/customs/DEA
  • Satellites for astronomy and military imaging
  • Mail/parcel screening
  • Screening by hospitals and EMS to identify unknown narcotics