Kagome superconductors structure revealed; compact 3D lidar sees non-reflective objects; chromo-encryption.
An international team of scientists and researchers from the Brown University lab are now able to describe the structure of the superconductor Kagome metals. The team used nuclear magnetic resonance (NMR) imaging and a quantum modeling theory to describe the microscopic structure as the metal changed states into a charge density wave (CDW) state at 103°Kelvin (about 275 below 0°Fahrenheit), the highest temperature known for superconducting behavior. Kagome (RbV3Sb5) is a newly discovered superconducting metal made from rubidium vanadium and antimony that shows different exotic properties as the material’s temperature is lowered. The material has a basket weave type structure. The team published its work in Physical Review Research.
“Microscopic nature of the charge-density wave in the kagome superconductor RbV3Sb5” Jonathan Frassineti, Pietro Bonfà, Giuseppe Allodi, Erick Garcia, Rong Cong, Brenden R. Ortiz, Stephen D. Wilson, Roberto De Renzi, Vesna F. Mitrović, and Samuele Sanna. Phys. Rev. Research 5, L012017 – Published 10 February 2023, DOI:https://doi.org/10.1103/PhysRevResearch.5.L012017
Researchers at Kyoto University in Japan have developed a 3D lidar system that can detect in-motion or stationery non-reflective objects using a beam-scanning-type laser source and a flash-type laser source on a single chip. The team used on-chip dually modulated photonic crystal lasers (DM-PCSELs) for both flash and beam-scanning sources and claim the lidar system can fit in the palm of a person’s hand.
“The DM-PCSEL integrates non-mechanical, electronically controlled beam scanning with flash illumination used in flash lidar to acquire a full 3D image with a single flash of light,” said study leader Susumu Noda, in a story on Optima’s website. “This unique source allows us to achieve both flash and scanning illumination without any moving parts or bulky external optical elements, such as lenses and diffractive optical elements.” According to the article, the flash source illuminates a wide field of view (30°×30°) and a beam-scanning source that provides spot illumination with 100 narrow laser beams. The dual light source is chip-based, which means it could lead to use in an on-chip, solid state system eventually.
Fig 1. Researchers developed a new nonmechanical 3D lidar system, which is the size of a business card (seen in front of the system on the left). The system uses dually modulated surface-emitting photonic-crystal lasers (DM-PCSELs) as flash and beam-scanning sources. Source: Susumu Noda, Kyoto University
The research was published in Optica.
Menaka De Zoysa, Ryoichi Sakata, Kenji Ishizaki, Takuya Inoue, Masahiro Yoshida, John Gelleta, Yoshiyuki Mineyama, Tomoyuki Akahori, Satoshi Aoyama, and Susumu Noda, “Non-mechanical three-dimensional LiDAR system based on flash and beam-scanning dually modulated photonic crystal lasers,” Optica 10, 264-268 (2023)
A new way to send encrypted messages uses colored light from silver nanostructures. Observant researchers from the Nanophotonics and Metrology Lab at Ecole Polytechnique Fédérale de Lausanne noticed that the silver nanostructure they were working on for another project reacted unexpected to polarized light. When shone through at a certain angle, the light reflected from the nanostructure in vivid, identifiable colors that made it possible to use for encryption. The researcher Olivier Martin and PhD student Hsiang-Chu Wang assigned the colors numbers, which they then used to represent letters using ASCII.
The researchers published their findings in Advanced Optical Materials:
Hsiang‐Chu Wang, Olivier J. F. Martin. “Polarization‐Controlled Chromo‐Encryption.” Advanced Optical Materials, 2023; 2202165 DOI: 10.1002/adom.202202165
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