Every frequency of light has special properties because it interacts with matter differently, and some frequencies are only just becoming accessible. Terahertz radiation exists between microwave and infrared frequencies, where light is able to penetrate many materials, including skin, but is much lower energy than X-rays. Producing and detecting terahertz radiation is not easy though, but researchers at the University of Michigan have created a new imaging system 1500 times more powerful than current systems.
To achieve this great increase in power, the researchers used lasers to create optical funnels with plasmons. Plasmons are coupled electrons and photons that travel across a metal's surface more efficiently than a photon will alone. By creating a funnel with them, terahertz photons will be directed to electrodes more quickly, so less energy is lost. This allows the device to create terahertz photons with 50 times more power and be 30 times more sensitive than other imaging systems.
The researchers expect they will be able to make the imaging system is more powerful by optimizing the plasmon funnels more. As this method addresses a fundamental issue of all photoconductive terahertz devices, it may be employed in more than just imaging systems in the future.
Source: University of Michigan