Phys.org September 6, 2024 Breaking the reciprocity of wave propagation is a problem of fundamental interest, and a much-sought functionality in practical applications, both in photonics and phononics. Although it has been achieved using resonant linear scattering from cavities with broken time-reversal symmetry, such realizations have remained inescapably plagued by inherent passivity constraints, which make absorption losses unavoidable, leading to stringent limitations in transmitted power. Researchers in Switzerland solved this problem by converting the cavity resonance into a limit cycle, exploiting the uncharted interplay between non-linearity, gain, and non-reciprocity. Strong enough incident waves could synchronize with these self-sustained oscillations and […]
Tag Archives: Wave propagation
Electromagnetic vortex cannon could enhance communication systems
Phys.org August 14, 2024 Toroidal electromagnetic pulses have been recently reported as non-transverse, space-time non-separable topological excitations of free space. However, their propagation dynamics and topological configurations have not been comprehensively experimentally characterized. The existing generators were limited in optical and terahertz domains; however, the feasibility and significance of generating such pulses at microwave frequencies have been overlooked. An international team of researchers (USA – Illinois Institute of Technology, China, Singapore) found that microwave toroidal pulses could be launched by a transient finite-aperture broadband horn antenna emitter, as an electromagnetic counterpart of “air vortex cannon.” Using this generator, they experimentally […]
Using magnetic worms to engineer nanoscale communication systems
Nanowerk July 15, 2020 High-frequency electromagnetic waves are used to transmit and process information in microelectronic devices. To gain a better understanding of precisely the way magnons behave and propagate in different structures researchers in Switzerland examined how electromagnetic waves propagate, and how they could be manipulated, in artificial ferromagnetic quasicrystals. They found that under controlled conditions a single electromagnetic wave coupled to an artificial quasicrystal splits into several spin waves which then propagate within the structure. Each of these spin waves represents a different phase of the original electromagnetic wave, carrying different information. By imaging wavefronts in quasicrystals, insight […]
First study of terahertz radiation in liquids
Phys.org November 29, 2018 The most common sources of terahertz radiation are solid materials. An international team of researchers (USA – University of Rochester, Russia) provides fundamental insights into the THz wave generation process in water and an alternative perspective for studying laser-induced breakdown in liquids. They substantiate the radiation patterns of terahertz radiation in a liquid and its dependence on the angle at which the liquid collides with the pump radiation. They plan to solve the problem of THz absorption by optimizing the type of fluid, the shape of the jet and the pump power and several other parameters. […]
Bursting the clouds for better communication
Phys.org October 18, 2018 Researchers in Switzerland have developed a laser that heats the air over 1,500 degrees Celsius and produces a shock wave to expel the suspended water droplets sideways. This creates a hole a few centimetres wide over the entire thickness of the cloud. The laser beam should be kept on the cloud and the laser that contains the information should be sent at the same time. It then slips into the hole through the cloud and allows the data to be transferred. This “laser cleaner” is currently being tested on artificial clouds that are 50 cm thick […]