Phys.org June 25, 2021 Light-in-flight sensing has emerged as a promising technique in image reconstruction applications at various wavelengths. A team of researchers in the US (NIST, industry, University of Colorado) has developed a microwave imaging system that uses an array of transmitters and a single receiver operating in continuous transmit-receive mode. Captures take a few microseconds, and the corresponding images cover a spatial range of tens of square meters with spatial resolution of 0.1 meter. The images are the result of a dot product between a reconstruction matrix and the captured signal with no prior knowledge of the scene. […]
New type of metasurface allows unprecedented laser control
Phys.org June 29, 2021 An international team of researchers (USA – Harvard University, Italy) has developed a tunable laser that has two components—a laser diode and a reflective metasurface. The metasurface surface uses supercells, groups of pillars which work together to control different aspects of light. It is designed so that only the selected wavelength has the correct direction to enter back in the diode enabling the laser to operate only at that specific wavelength. The wavelength can be changed by moving the metasurface with respect to the laser diode. The shape of the laser beam can be fully controlled […]
The pressure is off and high temperature superconductivity remains
Phys.org July 8, 2021 The grand challenge in superconductivity research and development is no longer restricted to further increasing the superconducting transition temperature under extreme conditions and must now include concentrated efforts to lower, and better yet remove, the applied pressure required. An international team of researchers (USA – Houston University, Rice University, China) has shown such a possibility in the pure and doped high-temperature superconductor FeSe by retaining, at ambient pressure via pressure quenching, its Tc up to 37 K and other pressure-induced phases. They observed that some phases remain stable without pressure at up to 300 K and […]
Quantum laser turns energy loss into gain
Phys.org July 7, 2021 Parity-time reversal symmetry in non-Hermitian systems realizes spontaneous symmetry breaking. A team of researchers in South Korea have demonstrated that such direct coupling can remodel conventional photonic platforms of non-Hermitian systems into polaritonic platforms with a single component; thus, improving the degrees of freedom of both integration and design for the coupled system. In this system, they found that as energy loss increased, the amount of energy needed to induce lasing decreased. By controlling the degree of loss between the microcavity and the semiconductor substrate the threshold energy becomes smaller as energy loss increases. According to […]
Researchers discover unusual competition between charge density wave and superconductivity
Phys.org July 5, 2021 To study the layered cage structure superconductor CsV3Sb5, which has a charge density wave (CDW) transition temperature of 94 K, researchers in China conducted high-pressure electrical transport and magnetic susceptibility measurements. They found that the CDW transition is monotonically suppressed by pressure, and superconductivity is enhanced with increasing pressure up to P1 ≈ 0.7 GPa. They found an unexpected suppression of superconductivity until pressure around 1.1 GPa, after that, Tc was enhanced with increasing pressure again. The CDW was completely suppressed at a critical pressure P2 ≈ 2 GPa together with a maximum Tc of about 8 K. The pressure-dependent Tc showed an unexpected […]
Researchers identify ultrastable single atom magnet
Phys.org July 7, 2021 An international team of researchers (South Korea, Germany) has shown that dysprosium (Dy) atoms on magnesium oxide (MgO) have a giant (magnet/ic anisotropy energy) MAE of 250 meV, currently the highest among all surface spins. Using a variety of scanning tunnelling microscopy (STM) techniques including single atom electron spin resonance (ESR), they confirmed that there was no spontaneous spin-switching in Dy over days at ≈ 1 K under low and even vanishing magnetic field. They utilized these robust Dy single atom magnets to engineer magnetic nanostructures, demonstrating unique control of magnetic fields with atomic scale tunability. The work […]
Stress-free path to stress-free metallic films paves the way for next-gen circuitry
Nanowerk July 4, 2021 To create thin films of tungsten with unprecedentedly low levels of film stress researchers in Japan have been working with scattering (HiPIMS), a sputtering technique. Using argon gas and a tungsten target, the team looked at how ions with different energies arrived at the substrate over time in unprecedented detail. Instead of using a bias pulse set off at the same time as the HiPIMS pulse, they used their knowledge of when different ions arrived and introduced a tiny delay, 60 microseconds, to precisely select for the arrival of high energy metal ions. They found that […]
Synthetic biology circuits can respond within seconds
MIT News July 1, 2021 A team of researchers in the US (MIT, research org, University of Wisconsin, Penn State College) created a bistable toggle switch in Saccharomyces cerevisiae using a cross-repression topology comprising 11 protein-protein phosphorylation elements. The toggle is ultrasensitive, can be induced to switch states in seconds, and exhibits long-term bistability. They developed a computational framework to search endogenous protein pathways for other large and similar bistable networks. The framework helped them to identify and experimentally verify five formerly unreported endogenous networks that exhibit bistability. Building synthetic protein-protein networks will enable bioengineers to design fast sensing and […]
Ultra-strong squeezing of light demonstrated for ultrafast optical signal processing
Phys.org July 6, 2021 An international team of researchers (Singapore, USA – MIT) succeeded in squeezing light in time by a factor of 11. They demonstrated 3.0× spectral compression of 480 fs pulses while preserving the pulse energy. The strong compression achieved at low powers harnesses advanced on-chip device design, and the strong nonlinear properties of backend-CMOS compatible ultra-silicon-rich nitride, which possesses absence of two-photon absorption and 500× larger nonlinear parameter than in stoichiometric silicon nitride waveguides. By balancing the contributions from the dispersive and nonlinear stages, they could generate strong compression in either time or frequency. The work introduces an […]
Ultrathin semiconductors are electrically connected to superconductors for the first time
Phys.org July 6, 2021 For future applications in electronics and quantum technology, researchers are focusing on the development of new components that consist of monolayer semiconducting material. An international team of researchers (Switzerland, Japan) has demonstrated superconducting vertical interconnect access (VIA) contacts to a monolayer of molybdenum disulfide (MoS2) using MoRe as a contact material. The electron transport was mostly dominated by a single superconductor/normal conductor junction with a clear superconductor gap. They found MoS2 regions that are strongly coupled to the superconductor resulting in resonant Andreev tunneling and junction-dependent gap characteristics, suggesting a superconducting proximity effect. Magnetoresistance measurements showed […]