Phys.org August 14, 2021 A team of researchers in the US (Harvard University, industry) has proposed a new class of computer-generated holograms, called Jones matrix holograms, whose far-fields have designer-specified polarization response. They have provided a simple procedure for their implementation using form-birefringent metasurfaces. Jones matrix holography generalizes past work with a consistent mathematical framework, particularly in the field of metasurfaces. They have demonstrated holograms whose far-fields implement parallel polarization analysis and custom waveplate-like behavior. The new approach could lead to applications in diverse fields including imaging, microscopes, displays, and astronomy. The work shows that the ability to switch between […]
Nanostructure-based lasers for information and communication technologies
Phys.org August 18, 2021 Key applications in 5G and 6G optical networks require the utilization of laser sources to perform complex tasks at ultra-fast speed and to enable broadband, secure and energy efficient communications. An international team of researchers (France, USA – University of New Mexico) reviews recent findings and prospects on nanostructure based light emitters where active region is made with quantum-dot and quantum-dash nanostructures. To link the material and fundamental properties with the device physics, they closely examined spectral linewidth, polarization anisotropy, optical nonlinearities as well as microwave, dynamic and nonlinear properties. The paper focuses on photonic devices […]
New salts raise the bar for lithium ion battery technology
Phys.org August 16, 2021 Lithium battery materials, currently in use, fall short in terms of safety and performance holding back the next generation of high-performance batteries. In particular, the development of the electrolyte poses a key challenge for higher power batteries suitable for energy storage and vehicle applications. Researchers in Australia have synthesized safe fluoroborate salts with battery grade purity by recrystallisation process. When put in a lithium battery with lithium manganese oxide cathodes, the cell cycled for more than 1000 cycles, even after atmospheric exposure. The salt was found to be very stable on aluminum current collectors at higher […]
On the road to faster and more efficient data storage
Phys.org August 18, 2021 Antiferromagnet is a promising candidate for developing the next generation of information technology. An international team of researchers (Germany, Sweden, Japan, Italy) showed that domain walls play an active role in the dynamic properties of the antiferromagnet nickel oxide. The experiments revealed that magnetic waves with different frequencies could be induced, amplified, and even coupled with each other across different domains—but only in the presence of domain walls. The ability highlights the potential to actively control the propagation of magnetic waves in time and space as well as energy transfer among individual waves at the femtosecond […]
A peculiar state of matter in layers of semiconductors
MIT News August 19, 2021 Experimental realization of many-body localization (MBL) in solid-state systems has remained challenging. A team of researchers in the US (MIT, Argonne National Laboratory, Brookhaven National Laboratory, University of Wisconsin, Oak Ridge National Laboratory, UC Santa Barbara, University of Pennsylvania) reports evidence of a possible phonon MBL phase in disordered GaAs/AlAs superlattices. Through grazing-incidence inelastic X-ray scattering, they observed a strong deviation of the phonon population from equilibrium in samples doped with ErAs nanodots at low temperature, signaling a departure from thermalization. This behavior occurs within finite phonon energy and wavevector windows, suggesting a localization-thermalization crossover. […]
Scientists Discover How to Make Glass So Hard, It Can Even Scratch Diamond
Science Alert August 13, 2021 An international team of researchers (China, Sweden, USA – Harvard university, Germany, Russia) has discovered the critical proportion of crystallized and amorphous carbon needed to create a glass with remarkable properties that won’t weaken under intense pressure. By subjecting spheres of carbon atoms to intense pressure and baking at temperatures between 1,000 and 1,200 degrees Celsius they obtained glassy materials dubbed AM – I, II and III. After tests they mapped the way the atoms bonded with one another, showing they all operated as a semiconductor on a level comparable with amorphous silicon. After Vickers […]
Scientists realize noiseless photon-echo protocol
Phys.org August 16, 2021 The intense spontaneous noise emission generated by photon echo is a fundamental tool for the manipulation of electromagnetic fields. However, it has the same frequency as the signal, and it is impossible to separate them in principle. Researchers in China have implemented a noiseless photon echo (NLPE) protocol in Eu3+:Y2SiO5 crystal to serve as an optical quantum memory and applied a four-level atomic system to suppress the noise. They manipulated the spontaneous noise emission to have a different frequency from the signal making it easier to separate the signal from the noise emission. Though other noises […]
‘Shadow waveguide’ casts complex acoustic patterns to control particles
Phys.org August 18, 2021 Despite all its potential, the acoustic tweezer technology makes it difficult to manipulate particles independently of one another or through complex patterns. To overcome the limitation of the acoustic tweezer a team of researchers in the US (Duke University, Rowan University) has demonstrated spatially complex particle trapping and manipulation inside a boundary-free chamber using a single pair of sources and an engineered structure outside the chamber that they call a shadow waveguide. The shadow waveguide creates a tightly confined, spatially complex acoustic field inside the chamber without requiring any interior structure that would interfere with net […]
Woven nanotube fibers turn heat into power
Phys.org August 16, 2021 Invisibly small carbon nanotubes aligned as fibers and sewn into fabrics become a thermoelectric generator that can turn heat from the sun or other sources into energy. An international team of researchers (USA – Rice University, Japan) made custom nanotube fibers and test their potential for large-scale applications. They fabricated a textile thermoelectric generator based on these carbon nanotube fibers, which demonstrated high thermoelectric performance, weavability, and scalability. The power factor they observed make these fibers strong candidates for the emerging field of thermoelectric active cooling, which requires a large thermoelectric power factor and a large […]
Top 10 Science and Technology Inventions for the Week of August 13, 2021
01. Metamaterials research challenges fundamental limits in photonics 02. New electronic phenomenon discovered 03. Non-line-of-sight imaging with picosecond temporal resolution 04. Protecting earth from space storms 05. Quantum materials cloak thermal radiation 06. Single-step synthesis of solid-state sensors for detecting explosives 07. Scientists develop chain mail fabric that can stiffen on demand 08. System trains drones to fly around obstacles at high speeds 09. 3D Kirigami Building Blocks Designed To Make Dynamic Metamaterial Structures 10. Anatomy of an earthquake series And others… Deconstructing the Infectious Biological Weaponry of the COVID-19 Virus Emergent magnetic monopoles controlled at room temperature Engineers clean […]