Phys.org August 19, 2019
An international team of researchers (France, Poland, Germany, Russia, Czech Republic) used a heavy metal alloy of mercury, cadmium and tellurium (HgCdTe) that is used for highly sensitive thermal imaging cameras. Mercury, cadmium and tellurium contents can be very precisely chosen, which makes it possible to fine-tune the band gap. The material showed properties similar to graphene, but without the issue of strong Auger scattering. When electric current is applied it gets rid of its energy in the form of terahertz radiation. By varying an additional magnetic field of only about 200 millitesla, the experts were able to vary the frequency of the emitted waves in a range of one to two terahertz—a tunable radiation source. It is not quite a laser yet, but rather like a terahertz LED. Up to now, the principle has only worked when cooled to very low temperatures, just above absolute zero therefore not suitable for everyday applications. But can be used in research and in certain high-tech systems…read more. TECHNICAL ARTICLE
An international research team has been able to show that it is relatively easy to generate terahertz waves with an alloy of mercury, cadmium and tellurium. Credit: HZDR / Juniks