Science Daily January 22, 2021 Researchers in Switzerland have developed metamaterial made of silicon and magnetic powder which has a complicated structure that allows mechanical properties to vary. Each cell within the structure behaves like an electrical switch. It is possible to activate and deactivate individual cells by applying a magnetic field which modifies the internal state of the metamaterial, and consequently its mechanical properties. The programmable material is analogous to computer devices like hard drives. The devices contain bits of data that can be written to and read from in real time. The cells in this programmable metamaterial, called […]
Tag Archives: S&T Switzerland
Optical wiring for large quantum computers
Phy.org October 22, 2020 The fundamental qualities of individual trapped-ion qubits are promising for long-term systems, but the optics involved in their precise control are a barrier to scaling. Researchers in Switzerland used scalable optics co-fabricated with a surface-electrode ion trap to achieve high-fidelity multi-ion quantum logic gates, which are often the limiting elements in building up the precise, large-scale entanglement that is essential to quantum computation. Light is efficiently delivered to a trap chip in a cryogenic environment via direct fibre coupling on multiple channels, eliminating the need for beam alignment into vacuum systems and cryostats and lending robustness […]
Turning streetwear into solar power plants
Nanowerk October 22, 2020 Luminescent solar concentrators (LSCs) absorb diffusive light and increase the cost-effectiveness of solar cells; however, the compatibility with flexible photovoltaics and the energy transfer (ET) efficiency still require improvement. Researchers in Switzerland used amphiphilic polymer conetworks (APCNs) as polymer matrices for wearable LSCs owing to their flexibility and wearability. Furthermore, with the assistance of APCNs’ nanophase separated hydrophobic and hydrophilic domains, hydrophobic and hydrophilic luminescent materials were loaded in adjacent nanometer-separated domains. This resulted in high ET rates and broadened the acceptor’s absorption range, rendering a more efficient down conversion emission. The re-emitted photons indicated that […]
Well-formed disorder for versatile light technologies
Nanowerk October 13, 2020 In nonlinear crystals, two photons of a particular frequency can be turned into one photon having twice that frequency if they are phase matched. This often severely limits practical applications. Researchers in Switzerland combined resonances and disorder by implementing random quasi-phase-matching in Mie resonant spheres of a few micrometres realized by the bottom-up assembly of barium titanate nanocrystals. The measured second-harmonic generation reveals a combination of broadband and resonant wave mixing, in which Mie resonances drive and enhance the second-harmonic generation, while the disorder keeps the phase-matching conditions relaxed. The nanocrystal assemblies provide new opportunities for […]
Ultrafast electrons in magnetic oxides: A new direction for spintronics?
Science Daily August 19, 2020 Special metal oxides could one day replace semiconductor materials that are commonly used today in processors. Until recently it had not been clear how the electron transfer across the band gap coupled with the spin of the magnetic oxide occurs. An international team of researchers (Germany, USA – research institute, Switzerland) was able to excite an electron to lift it across the band gap in nickel oxide. They also observed how the information was then transferred to the magnetic system. This enabled the team to identify a previously unknown ultrafast coupling mechanism that occurs on […]
Deep learning and metamaterials make the invisible visible
Nanowerk August 11, 2020 Due to the diffraction limit seeing and recognizing an object whose size is much smaller than the illumination wavelength is a challenging task for an observer placed in the far field. Researchers in Switzerland have demonstrated that combining deep learning with lossy metalenses allows recognizing and imaging largely subwavelength features directly from the far field. Their acoustic learning experiment shows that, despite being 30 times smaller than the wavelength of sound, the fine details of images can be successfully reconstructed and recognized in the far field, which is crucially favored by the presence of absorption. They […]
A new path for electron optics in solid-state systems
Science Daily July 14, 2020 Electron optics has been demonstrated mainly in one-dimensional devices, for example in nanotubes. Researchers in Switzerland have shown that the band inversion and hybridization present in two coupled semiconductor layers, consisting of InAs and GaSb system provide a novel transport mechanism that guarantees non-vanishing interference even when all angles of incidence occur. Through a combination of transport measurements and theoretical modelling, they found that their devices operate as a Fabry-Pérot interferometer in which electrons and holes form hybrid states. As the mechanism requires only band inversion and hybridization, the research opens engineering electron-optical phenomena in […]
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 […]
Adding noise for completely secure communication
Science Daily June 11, 2020 Device-independent quantum key distribution provides security even when the equipment used to communicate over the quantum channel is largely uncharacterized. A central obstacle in photonic implementations is that the global detection efficiency, i.e., the probability that the signals sent over the quantum channel are successfully received, must be above a certain threshold. Researchers in Switzerland developed a protocol that adds artificial noise, which cannot be known or controlled by an adversary, to the initial measurement data (the raw key). Focusing on a realistic photonic setup using a source based on spontaneous parametric down conversion, they […]
Combining magnetic data storage and logic
Phys.org June 16, 2020 Researchers in Switzerland built racetrack memory managed to perform logical operations directly within memory element. The racetrack memory elements work by using current pulses to move tiny magnetic domains up and down nanowires that are just a few hundred nanometres thick. In these domains, all the magnetic moments are oriented in the same direction and can thus be used to represent the binary states 0 and 1. They use an electric current to reverse the polarity of the magnetic regions, thereby performing a NOT operation on the stored data. By eliminating the need for the mechanical […]