Phys.org May 30, 2024 Creating dual-mode patterns in the same area of the material increases the dimension of information storage and encryption security. However different patterns may lead to serious mutual interference in the process of manufacturing and usage. An international team of researchers (USA – Argonne National Laboratory, China) has demonstrated noninterfering dual-mode patterns by combining the structural color and chromatic polarization, which was designed with an azobenzene-containing linear liquid crystal copolymer featuring a photofluidization effect. The secondary imprinting was used to eliminate the partial damage to the structural color patterns during writing of the polarization patterns, thus obtaining […]
Novel crystals enhance mid-infrared laser performance
Phys.org May 30, 2024 Researchers in China demonstrated a 978 nm laser diode (LD) side-pumped YSGG/Er:YSGG/YSGG composite crystal with a size of Ф 3 mm × 65 mm and continuous-wave (CW) mode. By optimizing resonator length and output mirror transmittance, a maximum output power of 28.02 W was generated, corresponding to slope efficiency of 17.55% and optical-optical efficiency of 12.29%, respectively. The thermal focal lengths were obtained by resonator stability condition. The laser wavelength was centered near 2.8 µm. Moreover, the beam quality factors 2/2 were fitted to be 8.14 and 7.35, respectively. The results indicated that a high-performance 2.8 µm CW laser could […]
On-chip GHz time crystals with semiconductor photonic devices pave way to new physics and optoelectronic applications
Phys.org May 31, 2024 Time crystals (TCs) are many-body systems that display spontaneous breaking of time translation symmetry. An international team of researchers (Argentina, Germany) demonstrated a TC by using driven-dissipative condensates of microcavity exciton-polaritons, spontaneously formed from an incoherent particle bath. The TC phases were controlled by the power of a continuous-wave nonresonant optical drive exciting the condensate and the interaction with cavity phonons. The TC phases were, for increasing power, locking of the frequency of precession to self-sustained coherent phonons—stabilized TC; and doubling of TC’s period by phonons. According to the researchers the results established microcavity polaritons as […]
Study identifies fungus that breaks down ocean plastic
Phys.org June 3, 2024 Plastic may serve as a potential carbon and energy source for microbes, yet the contribution of marine microbes, especially marine fungi to plastic degradation is not well constrained. An international team of researchers (the Netherlands, France, Denmark, Switzerland) isolated the fungus Parengyodontium album from floating plastic debris and measured fungal-mediated mineralization rates (conversion to CO2) of polyethylene (PE). When the PE was pretreated with UV light, the biodegradation rate of the initially added PE was 0.044 %/day. They traced the incorporation of PE-derived 13C carbon into P. album biomass. Despite the high mineralization rate incorporation of […]
Study reveals potential of superparaelectric materials as gate dielectrics in next-gen microelectronics
Phys.org May 30, 2024 Previous investigations for thickness-scalable high dielectric constant (k) gate layers have failed to solve the “polarizability–scalability–insulation robustness issues. An international team of researchers (UK, China) showed that this problem could be solved by using a gate layer of a high k ferroelectric oxide in its superparaelectric (SPE) state. They showed that in the SPE, the polar order became local and was dispersed in an amorphous matrix with a crystalline size down to a few nanometers, leading to an excellent dimensional scalability and a good field-stability of the k value. As an example, a stable high k […]
Team of international experts call for urgent action against increasing threat from invasive species
Phys.org June 3, 2024 According to a critical evaluation by the 88 authors, representing 101 organizations from 47 countries, urgent action is needed to curb the major and growing threats from invasive alien species, a major threat to nature and people, all over the world. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) Thematic Assessment Report on Invasive Alien Species and Their Control (hereafter ‘IPBES invasive alien species assessment’) drew on more than 13,000 scientific publications and reports in 15 languages as well as Indigenous and local knowledge on all taxa, ecosystems and regions across the globe. Therefore, […]
A technique for more effective multipurpose robots
MIT News June 3, 2024 Existing robotic datasets vary in different modalities such as color, depth, tactile, and proprioceptive information, and collected in different domains. Current methods usually collect and pool all data from one domain to train a single policy to handle such heterogeneity in tasks and domains, which is prohibitively expensive and difficult. Researchers at MIT presented a flexible approach, called Policy Composition, to combine information across such diverse modalities and domains for learning scene-level and task-level generalized manipulation skills, by composing different data distributions represented with diffusion models. Their method could use task-level composition for multi-task manipulation […]
Tonga’s volcanic eruption could cause unusual weather for the rest of the decade, new study shows
Phys.org May 30, 2024 The amount of water vapor injected into the stratosphere after the eruption of Hunga Tonga-Hunga Ha’apai (HTHH) was unprecedented, and it is therefore unclear what it might mean for surface climate. Researchers in Australia used chemistry climate model simulations to assess the long-term surface impacts of stratospheric water vapor (SWV) anomalies similar to those caused by HTHH, but neglected the relatively minor aerosol loading from the eruption. The simulations showed that the SWV anomalies led to strong and persistent warming of Northern Hemisphere landmasses in boreal winter, and austral winter cooling over Australia, years after eruption, […]
Towards next-gen functional materials: direct observation of electron transfer in solids
Science Daily June 4, 2024 Nanoscale electron transfer (ET) in solids is fundamental to the design of multifunctional nanomaterials, yet its process is not fully understood. Researchers in Japan directly observed solid-state ET via a crystal-to-crystal process. They first demonstrated the creation of a robust and flexible electron acceptor/acceptor (A/A) double-wall nanotube crystal with a large window through the one-dimensional porous crystallization of heteroleptic Zn4 metallocycles with two different acceptor ligands. They constructed the electron donor incorporated-A/A nanotube crystal through the subsequent absorption of electron donor guests. They removed electrons from the electron donor guests inside the nanotube crystal through […]
Ultra-thin infrared filter, thinner than cling wrap, revolutionizes night vision
Nanowerk June 3, 2024 The ability to detect and image short-wave infrared light has important applications in surveillance, autonomous navigation, and biological imaging. However, the current infrared imaging technologies often pose challenges due to large footprint, large thermal noise and inability to augment infrared and visible imaging. An international team of researchers (Australia, Germany) demonstrated infrared imaging by nonlinear up-conversion to the visible in an ultra-compact, high-quality-factor lithium niobate resonant metasurface. Despite the strong nonlocality of the metasurface they obtained images with high conversion efficiency and resolution quality. They showed the possibility of edge-detection image processing augmented with direct up-conversion […]