THz Science & Technology

Welcome

To the Terahertz Science & Technology website of the Optics Research Group. On these pages, you'll find pdf's of many scientific publications in peer-reviewed journals, but also some descriptions of the work that we do aimed at a more general audience.

The images above are THz images of a leaf. This is nothing new as one of the first THz images made at AT&T Bell labs was, in fact, of a leaf (B. B. Hu and M. C. Nuss, Opt. Lett. 20, 1716 (1995)). The left image shows the THz tranmission, indicated in false color, of a wet leaf. The second image is the phase image of the same leaf. The phase provides a measure for the time it takes for the THz light to travel through the leaf. The rectangular feature is the double-sticky tape used to stick the leaf to the polystyrene foam sample holder. This, incidentally show how the different properties of a material, such as absorption coefficient and refractive index, can all be measured and imaged using our THz imaging techniques. Each of these material properties gives a different contrast mechanism, so that in the case of the phase, which predominantly samples the THz optical refractive index, the rectangular patch shows up more clearly than in the absorption/scattering image. Finally, the image on the right is the THz transmission image of the same leaf, a few days later.THz radiation, or far-infrared radiation, is light with a frequency in the range of 0.1 to 30 THz. This range is a largely underexplored spectral region in which we pursue both applied and fundamental research. 

Above is an other THz image. We used THz radiation to look through a codekey. THz radiation easily passes through the plastic, but is blocked by the small magnets inside. White spots indicate positions where there are no magnets. As you can see, we have the ability to look inside things. You'll find more conventional THz images here. If you want a little background on THz radiation, you are invited to read the introduction to THz radiation. You can also visit our FAQ page.

THz projects (present and past)

• Terahertz generation from graphite (link)
• Terahertz electric near-field of a hole (link)
• Identification of the polymorphs of Mannitol using THz radiation (link)
• Orientation dependence of THz pulse detection in ZnTe
• THz emitter with a record dynamic range, based on a Ti:sapphire oscillator
• THz dielectric properties of polystyrene foam
• THz microscope: micrometer resolution with millimetre waves
• more projects...

THz publications

We have collected all the publications of our group in this page with extra links to explain the papers.