Nanowerk July 30, 2021 Incoming light can hit the electrons in the semiconductor lattice and move them to a higher energy state creating an electric field which further accelerates the high-energy electrons. They unload the extra energy by radiating it at different optical wavelengths, thus converting the wavelengths. An international team of researchers (USA – UCLA, Iowa State University, Germany) devised a solution for improving wavelength conversion using the semiconductor surface state phenomenon. They incorporated a nanoantenna array that bends incoming light, so it is confined around the shallow surface of the semiconductor converting the wavelength easily and without any […]
Tag Archives: Communications technology
World’s first commercial re-programmable satellite blasts into space
Phys.org July 30, 2021 The European Space Agency launched the world’s first commercial fully re-programmable satellite from French Guiana on Friday [July 30, 2021] ushering in a new era of more flexible communications paving the way for a new era of more flexible communications. Unlike conventional models that are designed and “hard-wired” on Earth and cannot be repurposed once in orbit, the Eutelsat Quantum allows users to tailor the communications to their needs—almost in real-time. Because it can be reprogrammed while orbiting in a fixed position 35,000 kilometres (22,000 miles) above the Earth, the Quantum can respond to changing demands […]
New quantum research gives insights into how quantum light can be mastered
Phys.org July 22, 2021 Researchers at Los Alamos National Laboratory propose that modulated quantum metasurfaces can control all properties of photonic qubits, a breakthrough that could impact the fields of quantum information, communications, sensing and imaging, as well as energy and momentum harvesting. They developed a metasurface that looked like an array of rotated crosses, then proposed to shoot a single photon through the metasurface, where the photon splits into a superposition of many colors, paths, and spinning states generating quantum entanglement meaning the single photon can inherit different properties at once. According to the researchers by manipulating these properties, […]
Quantum holds the key to secure conference calls
EurekAlert June 6, 2021 Traditional quantum communication protocols consume pair-wise entanglement, which is suboptimal for distributed tasks involving more than two users. An international team of researchers (UK, Germany) has demonstrated quantum conference key agreement leveraging multipartite entanglement to efficiently create identical keys between N users with up to N-1 rate advantage in constrained networks. They distributed four-photon Greenberger-Horne-Zeilinger (GHZ) states, generated by high-brightness telecom photon-pair sources over optical fiber with combined lengths of up to 50 km and performed multiuser error correction and privacy amplification. Under finite-key analysis, they established 1.5 × 106 bits of secure key, which were […]
Exploiting non-line-of-sight paths for terahertz signals in wireless communications
EurekAlert April 27, 2021 A team of researchers in the US (Rice University, Brown University) investigated the idea of harnessing these specular NLOS (Non-Line-Of-Sight) paths for communication in directional networks at frequencies above 100 GHz. They explored several illustrative transmitter architectures, such as conventional substrate-lens dipole antenna and a leaky-wave antenna, to learn how these high-gain directional antennas offer both new challenges and new opportunities for exploiting NLOS paths. The results demonstrated the sensitivity to antenna alignment, power spectrum variations, and the disparity in supported bandwidth of various line-of-sight (LOS) and reflected path configurations. They showed that NLOS paths can, […]
New laser to help clear the sky of space debris
Phys.org April 12, 2021 The laser beams used for tracking space junk use infrared light and are not visible. The new guide star laser, which is mounted on a telescope, developed by an international team of researchers (from Australia, Japan, USA) propagates a visible orange beam into the night sky to create an artificial star that can be used to accurately measure light distortion between Earth and space. This guiding orange light enables adaptive optics to sharpen images of space debris. It can also guide a second, more powerful infra-red laser beam through the atmosphere to precisely track space debris or […]
Researchers establish the first entanglement-based quantum network
Phys.org April 15, 2021 Researchers in the Netherlands have built a three-node entanglement-based quantum network by combining remote quantum nodes based on diamond communication qubits into a scalable phase-stabilized architecture, supplemented with a robust memory qubit and local quantum logic. They achieved real-time communication and feed-forward gate operations across the network. They demonstrated two quantum network protocols without postselection: the distribution of genuine multipartite entangled states across the three nodes, and entanglement swapping through an intermediary node. The work establishes a key platform for exploring, testing, and developing multinode quantum network protocols and a quantum network control stack…read more. TECHNICAL […]
Detecting photons transporting qubits without destroying quantum information
Phys.org March 25, 2021 Photons that carry qubits over long distances are easily deflected from their path in the air or absorbed in glass fibers—and suddenly, the quantum information is lost. An international team of researchers (Germany, Spain) has developed a physical protocol that can indicate whether the qubit is lost at intermediate stations of the quantum transmission. If this is the case, the transmitter can send the qubit again with significantly less delay than if the loss is noticed only at the receiving end. The protocol only detects the qubit photon and not measure it. They achieved a nondestructive […]
Looking at optical Fano resonances under a new light
Phys.org March 19, 2021 Fano resonances are conventionally understood as sharp spectral features that can be excited only by plane waves with specific frequencies and incident angles. Researchers at the City University of New York proved that they can be tailored to resonate only when excited by a frequency, polarization, and wavefront of choice. This generalization reveals that Fano systems are characterized by eigenwaves that scatter to their time-reversed image upon reflection. They showed that the selected wavefront is locally retroreflected everywhere across the device. These results show that conventional Fano resonances are a subset of a broader dichroic phenomenon […]
When memory qubits and photons get entangled
Phys.org March 15, 2021 The implementation of efficient interfaces between photons and stationary qubits is crucial for the rate of information transfer and the scalability of a quantum network. With their experimental setup researchers in Germany demonstrated quantum entanglement between a stationary qubit and a photon out of an optical fiber resonator. They showed the generation of deterministic entanglement at a high fidelity of 90.1(17)% between a trapped Yb ion and a photon emitted into the resonator mode. And achieved a success probability for generation and detection of entanglement for a single shot of 2.5 × 10−3 resulting in 62 Hz entanglement rate. […]