The intrinsic properties of terahertz (THz) technology result in a wide scope of potential sensing and imaging applications, with its use representing a tremendous added value over other wavelengths of light, such as X-ray or infrared:
- Its nonionizing nature (unlike X-rays, for example) makes it safe for use on biological tissues (e.g. the human body).
- It can penetrate fabrics and plastics, allowing for nondestructive inspection of these materials and scanning underneath these layers.
- It cannot penetrate water or metal, enable its use for analysis of hydration levels or detecting the presence of metallic components in samples.
- Many materials have unique spectral fingerprints in the THz range, such as different types of explosives or several compounds used in the fabrication of medicines. THz would be ideal for detection of these components in samples.
- For pulsed THz sources, the ultrashort width of its pulse allows for measurements (e.g. thickness, density, defect location) on difficult to probe materials, such as foam.
The production of Terahertz waves can be divided into purely electronic sources and laser-driven / optoelectronic ones. The latter can then be split into pulsed and continuous-wave (CW) terahertz radiation, the second of which allows for frequency selectivity – which means that the source wavelength can be precisely selected and tailored to a specific task.
CW terahertz waves are produced when two laser diodes with adjacent wavelengths are combined and focused on a photomixer, producing a new laser beam in the terahertz frequency range. As the detector records the terahertz wave coherently (meaning both the amplitude and the phase of the signal are recovered), the technology allows for a more complete analysis of the sample under investigation.
Production and detection of THz waves remains technically challenging and expensive, preventing its broader use in many application domains.
State-of-the-art CW THz production / detection uses a single photomixer with limited power with imaging being performed by scanning.
Imec’s solution makes use of photonic integrated chips to realize compact THz imaging at a much lower cost and high performance.
- The emitter array generates narrow, high intensity, steerable beams like radar imaging.
- The detector array allows for a fast, coherent detection of terahertz waves.Each pixel in the emitter and detector arrays is optically driven by an onchip laser/amplifier.
- Each pixel is phase modulated dynamically via a special algorithm, allowing real time imaging.
- Waveguides distribute laser power to each pixel in the array.
- Pumping lasers, amplifiers and phase modulators are all integrated resulting a compact size with reduced fabrication cost.
The non-ionizing features of THz waves allow to penetrate many materials, making the technology suitable for non-destructive testing in a number of industries:
- Concrete inspection (defects, corrosion on reinforcing bars, water diffusion, cracks)
- Surface corrosion in shielded copper conductors
- Ceramic tile adhesion detection
- Mechanical deformation of polymers
- Insulation in buildings and space stations
- Building inspection
The non-ionizing nature of THz waves also makes it a much safer alternative to the use of X-rays for medical imaging applications; and it comes with some additional benefits:
- Cancer imaging: the distinct absorption and refraction lines within the 0.5 – 1.5 THz range of cancer tissue makes THz technology ideal for cancer imaging.
- Dental imaging: the non-ionizing features of THz technology enable a regular, fast, non-invasive scanning of the teeth with the use of a portable dentist probe, allowing for early detection of tooth decay during regular medical appointments.
- Multi-spectral THz colonoscopy: THz technology can be combined with the traditional camera approach for both a visual and multispectral THz examination, enabling the inner layers of the large intestine to be visualized as well.
THz imaging can be used to measure tissue hydration, melanin content, hemoglobin levels.
Agriculture and food
The distinct absorption lines within different ranges of the THz spectrum of different pesticides and other organic materials make THz technology ideal to detect their presence in soils and food. The fact that water is opaque to THz radiation also allows for detection of their hydration levels.
What can we do for you?
- Demonstration of imec’s CW THz device/system
- Align R&D activity with imec
- Provide prototype devices for evaluation
- Receive support in technology evaluation
- Collaborate on Thz applications
- We offer flexible collaboration models ranging from collaboration on proposal submission, pure contract research for concept design, prototyping and low volume manufacturing, to full support in THz photomixer technology transfer and licensing.
- We offer custom product development using our THz emitter/detector technology with strong engagement model of collaboration matching your own internal R&D team objectives.
Why work with us?
- Our comprehensive expertise includes photonics circuits simulation and design, Si/Ge photomixer design and fabrication, and more.
- Our THz research laboratory has state-of-the-art CW and pulsed THz lasers and spectrometers. We can provide our customers with application recommendation and evaluation.
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