Phys.org December 17, 2018 An international team of researchers (USA – MIT, University of Hartford, UK. France) found that several materials with poor nonlinear characteristics can be combined, resulting in a new metamaterial that can be “tuned” to change the color of light. The enhancement comes from the way the metamaterial reshapes the flow of photons. They describe the underlying physics, compare its predictions to the experimental results, and analyze the limits of its applicability. The work opens a new direction in controlling the nonlinear response of materials and may find applications in on-chip optical circuits, drastically improving on-chip communications…read […]
Tag Archives: Communications technology
Shape-shifting origami could help antenna systems adapt on the fly
Tech Explore December 10, 2018 Researchers at the Georgia Institute of Technology focused on Miura-Ori, which has the ability to expand and contract like an accordion, to create radio frequency filters that have adjustable dimensions, enabling the devices to change which signals they block throughout a large range of frequencies. They used a special printer that scored paper to allow a sheet to be folded in the origami pattern. An inkjet-type printer was then used to apply lines of silver ink across those perforations, forming the dipole elements that gave the object its radio frequency filtering ability. They found that […]
Changing color of light using a spatiotemporal boundary
Phys.org November 29, 2018 Effective temporal control of the medium is critical for frequency conversion. Researchers in South Korea designed a metasurface for the sudden merging of two distinct metallic meta-atoms into a single one upon ultrafast optical excitation. Sudden merging creates a spectrally designed temporal boundary on the metasurface by which the frequency conversion can be achieved and engineered. The technique provides a spatiotemporal boundary as a platform for freely designing and changing the spectral properties of the medium. Since frequency conversion can be observed even in weak light, this technique could be particularly useful in communication technology…read more. […]
QuTech researchers put forward a roadmap for quantum internet development
Delft University of Technology (the Netherlands) October 18, 2018 Researchers in the Netherlands describe six phases, starting with simple networks of qubits that could already enable secure quantum communications – a phase that could be reality in the near future. The development ends with networks of fully quantum-connected quantum computers. In each phase, new applications become available such as extremely accurate clock synchronization or integrating different telescopes on Earth in one virtual ‘supertelescope’. This work creates a common language that unites the highly interdisciplinary field of quantum networking towards achieving the dream of a world-wide quantum internet… read more. TECHNICAL […]
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 […]
Security vulnerabilities in terahertz data links
Science Alert October 15, 2018 Unlike microwaves, which propagate in wide-angle broadcasts, terahertz waves travel in narrow, very directional beams with a cone angle of less than 2 degrees. A team of researchers in the US (Brown University, Rice University, SUNY Buffalo) set up a direct line-of-site terahertz data link between a transmitter and receiver and experimented with devices capable of intercepting signal. They were able show several strategies that could steal signal without being detected by using a flat piece of metal that could redirect a portion of the beam to a secondary receiver operated by an attacker…read more. […]
Measurement-device-independent quantum communication without encryption
Phys.org October 11, 2018 The key problem of practical quantum secure direct communication (QSDC) is that apparatuses used in practical quantum communication systems have some defects, and these imperfections, especially defects in the measurement devices, can lead to leakage of information and affect the security of practical QSDC. Researchers in China proposed a measurement-and-device-independent quantum secure direct communication protocol using Einstein-Podolsky-Rosen pairs. This protocol eliminates all loopholes related to measurement devices, which solves a key obstacle in practical quantum secure direct communication. The protocol has also an extended communication distance, and a high communication capacity…read more. TECHNICAL ARTICLE
Quantum technologies can be applied on a standard telecommunications network
Phys.org October 4, 2018 Researchers in Spain have developed a quantum cryptography network integrated in a commercial optical network through technologies based on software defined networking allowing for the implementation of quantum and classical network services in a flexible, dynamic and scalable manner. The technology has been developed on an existing infrastructure using standard communications systems and allows switching between links connecting points that may be up to 60 kilometers apart. Twenty channels can share the same fiber in the same optical band that uses the quantum channel, allowing the simultaneous transmission of quantum signals with more than two terabytes […]
On-demand room-temperature single photon array—a quantum communication breakthrough
Phys.org September 21, 2018 An international team of researchers (USA – City College of New York, Australia, Lithuania) has demonstrated large arrays of room-temperature quantum emitters in two-dimensional hexagonal boron nitride. The large energy gap inherent in substrate-induced deformation in hBN stabilizes the emitters at room temperature within nanoscale regions. Combining analytical and numerical modeling, they showed that emitter activation is the result of carrier trapping in deformation potential wells. The breakthrough has solved a long-standing and practical hurdle of realizing deterministic single photon emitters at room temperature… read more. Open Access TECHNICAL ARTICLE
Optical neural network demo
Science Daily July 28, 2018 Researchers at NIST stacked waveguides made of silicon nitride to form a three-dimensional grid with 10 inputs or “upstream” neurons each connecting to 10 outputs or “downstream” neurons, for a total of 100 receivers. They created software to automatically generate signal routing, with adjustable levels of connectivity between the neurons. Laser light was directed into the chip through an optical fiber routing each input to every output group, following a selected distribution pattern for light intensity or power. To evaluate the results, researchers made images of the output signals. The output was highly uniform, with […]