Phys.org August 8, 2023 Orbital angular momentum (OAM) spectrum diagnosis is a fundamental building block for diverse OAM-based systems. Among others, the simple on-axis interferometric measurement can retrieve the amplitude and phase information of complex OAM spectra in a few shots. Yet, its single-shot retrieval remains elusive, due to the signal–signal beat interference inherent in the measurement. Researchers in Switzerland have introduced the concept of Kramers–Kronig (KK) receiver in coherent communications to the OAM domain, enabling rigorous, single-shot OAM spectrum measurement. They explained in detail the working principle and the requirement of the KK method and applied the technique to […]
Tag Archives: S&T Switzerland
Scientists improve the accuracy of weather and climate models
Phys.org March 1, 2023 Researchers in Switzerland have developed a new modelling framework for atmospheric flow simulations for cryospheric regions called CRYOWRF. CRYOWRF couples the state-of-the-art and used atmospheric model WRF (the Weather Research and Forecasting model) with the detailed snow cover model SNOWPACK. CRYOWRF makes it feasible to simulate the dynamics of a large number of snow layers governed by grain-scale prognostic variables with online coupling to the atmosphere for multiscale simulations from the synoptic to the turbulent scales. They also introduced a scheme for blowing snow in CRYOWRF. They described the technical design goals, model capabilities and the […]
New technology revolutionizes the analysis of old ice
Science Daily February 16, 2023 The objective of EPICA [European Project for Ice Coring in Antarctica] is to look back 1.5 million years into the past and obtain data on the development of temperature, the composition of the atmosphere and the carbon cycle. A depth of around 2700 meters must be reached in the Antarctic ice sheet and an ice core recovered which they plan to accomplish by 2025. In the 1.5-million-year-old ice, 15,000 to 20,000 years of climate history are compressed into just one meter of ice core, which places completely new demands on ice core analyzes. Researchers in […]
Solids that are also liquids: Elastic tensors of superionic material
Phys.org January 30, 2023 Superionics display both solid- and liquid-like characteristics: as solids, they respond elastically to shear stress; as liquids, they display fast-ion diffusion at normal conditions. They are technologically relevant for energy, electronics, and sensing applications. Characterizing and understanding their elastic properties are needed to address their feasibility as solid-state electrolytes in all-solid-state batteries. However, static approaches to elasticity assume well-defined reference positions around which atoms vibrate, in contrast with the quasi-liquid motion of the mobile ions in fast ionic conductors. Researchers in Switzerland have derived the elastic tensors of superionics from ensemble fluctuations in the isobaric-isothermal ensemble, exploiting extensive Car-Parrinello simulations. They applied this approach to […]
A quantum pump without a crank
Phys.org August 22, 2022 The pumping process can have topological origins, when considering the motion of quantum particles in spatially and temporally periodic potentials. However, the periodic evolution that drives these pumps has always been assumed to be imparted from outside. Researchers in Switzerland found an emergent mechanism for pumping in a quantum gas coupled to an optical resonator, where they observed a particle current without applying a periodic drive. The pumping potential experienced by the atoms is formed by the self-consistent cavity field interfering with the static laser field driving the atoms. The cavity field evolves between its two […]
A paper battery with water switch
Nanowerk July 29, 2022 Researchers in Switzerland have developed a disposable paper battery aiming to reduce the environmental impact of single-use electronics for applications such as point of care diagnosis, smart packaging, and environmental sensing. The battery uses Zinc as a biodegradable metal anode, graphite as a nontoxic cathode material and paper as a biodegradable substrate. To facilitate additive manufacturing, they developed electrodes and current collector inks that can be stencil printed on paper to create water-activated batteries of arbitrary shape and size. The battery remains inactive until water is provided and absorbed by the paper substrate, taking advantage of […]
Light amplification accelerates chemical reactions in aerosols
Science Daily April 14, 2022 Researchers in Switzerland reported that optical confinement could create spatial structuring of the light intensity inside the particle and thereby cause corresponding variations of photochemical rates. They probed single iron(III)–citrate particles using the iron oxidation state as a photochemical marker. Based on the results, they predicted an overall acceleration of photochemical reactions by a factor of two to three for most classes of atmospheric aerosol particles. Rotation of free aerosol particles and intraparticle molecular transport generally accelerate the photochemistry. According to the researchers, given the prevalence of optical confinement effects, their influence on aerosol particle […]
Researchers develop glass-in-glass fabrication approach for making miniature IR optics
Phys.org April 7, 2022 Glass that transmits IR wavelengths is essential for many applications. However, infrared glasses are difficult to manufacture, fragile and degrade easily in the presence of moisture. Researchers in Switzerland have developed a new technique where they created an arbitrarily shaped 3D cavity inside a fused silica glass substrate using femtosecond laser-assisted chemical etching. They used a miniaturized version of pressure-assisted casting, in which a second material was melted and pressurized so that it could flow and solidify within the network of carved silica cavities. The second material can be a metal, glass, or any material with […]
Cooling matter from a distance
Science Daily February 2, 2022 Researchers in Switzerland succeeded in forming a control loop consisting of two quantum systems separated by one meter. Within this loop a vibrating membrane was cooled by a cloud of atoms, and the two systems were coupled to one another by laser light. As one of the systems acts as a control unit for the other, no measurement is needed. Instead, the control system is configured to bring the target system into a desired state by means of coherent quantum mechanical interaction. They successfully used this coherent feedback mechanism to reduce the temperature of the […]
Creating cotton that is fireproof and comfortable
Phys.org September 15, 2021 Researchers in Switzerland utilized a tri-functional phosphorous compound (trivinylphosphine oxide), which has the capability of reacting only with specifically added molecules (nitrogen compounds like piperazin) to form its own network inside cotton. This makes the cotton permanently fire-resistant without blocking the favorable -OH groups. This flame retardant treatment does not include carcinogenic formaldehyde. The phosphine oxide networks do not wash out. After 50 launderings, 95 percent of the flame retardant network was still present in the fabric. To fix the phosphine oxide networks inside the cellulose they treated the cotton with an aqueous solution of phosphorus […]