New Technique Discovered for Creating Terahertz Radiation

[Guest_Jim_*]

When X-ray photography was first discovered, it allowed us to peer into places previously impossible, and we may see a revolution like that happen again with terahertz radiation. Though at a much lower frequency, this form of light can be used to identify various illnesses and materials, at range and without damaging the subject. To best accomplish this though, a wide range of frequencies need to be created, and researchers at the University of Rochester have found a new way of doing so at a lower power than thought possible.

Specific frequencies of terahertz radiation can be made by special diodes and lasers, but these are only good for imaging work. Spectroscopy, which identifies materials by how light interacts with it, requires a broadband light source, which is made by a microplasma. To produce such a plasma requires either two powerful lasers of different frequencies, or one even more powerful laser. The Rochester researchers wondered if maybe working with special polarizations of light could improve efficiencies. It turns out this is not the case, but once the researchers learned why this did not work and the underlying physics, they found another solution. This new approach allows for the creation of the microplasma with a single laser at a much lower power than previously thought possible, and it may go even lower, by changing the gas used.

One thing interesting about this technique is that the terahertz waves go in a different direction than the laser beam, which should make it easier to couple the waves to a waveguide in a microchip.

Source: University of Rochester

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