Phys.org October 26, 2021 Researchers in China made laser-driven terahertz emitters, consisting of metasurface-patterned magnetic multilayer heterostructures that can overcome the shortcomings of the conventional approaches. They have demonstrated the efficient generation and manipulation of broadband chiral terahertz waves. The emitter’s ellipticity can reach >0.75 over a broad terahertz bandwidth (1 to 5 THz), it is an efficient source for few-cycle circularly polarized terahertz pulses with stable carrier waveforms, and has flexible control of ellipticity and helicity. They have shown that the terahertz polarization state is dictated by the interplay between laser-induced spintronic-origin currents and the screening charges/currents in the […]
Category Archives: Terahertz radiation
Scientists develop ultra-thin terahertz source
Phys.org March 30, 2021 One of the biggest challenges in terahertz technology is that commonly accepted ‘intense terahertz source’ is faint and bulky. To overcome these limitations researchers in the UK developed terahertz sources from extremely thin materials (about 25 atomic layers). By illuminating an electronic-grade semiconductor with two different types of lasers light, each oscillating at different frequency they were able to elicit the emission of short bursts of Terahertz radiation. The emission region of their new development, a semiconductor source of terahertz, is 10 times thinner than previously achieved, with comparable or even better performances. They are able […]
Terahertz radiation can disrupt proteins in living cells
EurekAlert June 2, 2020 Because terahertz radiation is stopped by liquids and is non-ionizing it is considered generally safe for use in the airports for scanning passengers. However, researchers in Japan have discovered that the energy from the light could enter into water as a “shockwave.” They investigated (G)-actin and (F)-actin, which have different structures and functions. Looking at the effect of terahertz radiation on the growth of chains in an aqueous solution of actin, they found that it led to a decrease in filaments, preventing the (G)-actin from forming chains and becoming (F)-actin. Ruling out the rise in temperature, […]
Record-breaking terahertz laser beam
Phys.org January 20, 2020 An international team of researchers (Greece, Austria, Qatar, Russia, Lithuania) has experimentally demonstrated that two-color filamentation of femtosecond mid-infrared laser pulses at 3.9 μm allows one to generate ultrashort sub-cycle THz pulses with sub-milijoule energy and THz conversion efficiency of 2.36%, resulting in THz field amplitudes above 100 MV cm−1. Numerical simulations predict that the observed THz yield can be significantly upscaled by further optimizing the experimental setup. They showed that the generated THz pulses are powerful enough to induce nonlinear cross-phase modulation in electro-optic crystals. The work paves the way toward free space extreme nonlinear THz optics using […]
A laser for penetrating waves
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 […]