. | . |
Scientists optimized technology for production of optical materials for microelectronics by Staff Writers Vladivostok, Russia (SPX) Feb 05, 2021
Scientists of Far Eastern Federal University (FEFU) have advanced the technology of high-speed sintering for optical ceramics (Nd3+:YAG), i.e. active elements generating laser emission in the near-infrared wavelength range (1.06 um) for cutting the edge microelectronics and medicine. The researchers have managed to reduce significantly the initial nanopowders consolidation period (10 - 100 times) forming a nanostructure with ensured high optical transparency of the ceramic material. A related article appears in Optical Materials. Diode-pumped microlasers based on Nd3+:YAG nanoceramics, due to their short lasing pulse duration, high peak power, and beam quality in combination with the elements' small size, are relevant for the ranging, telecommunications, space technology, industry, and medicine. Introduced a new approach to the technology of high-speed synthesis, young FEFU scientists achieved the optical quality of experimental ceramic materials at the level of world developments and commercial analogs. For that, they had combined the stages of the solid-state synthesis of the Nd3+:YAG structure from the initial Nd2O3, Y2O3, and Al2O3 oxide nanopowders, and its spark plasma sintering (SPS). "The affectation of the SPS-technology is ceramics contaminates with carbon-containing impurities from the graphite parts of the set-up during sintering. For example, on carbides basis, new chemical compounds can form in the glassy and/or crystalline state, gas impurities, etc. Unwanted inclusions can dramatically reduce the transparency of optical materials and lead to the degradation of their mechanical characteristics. Our main task was to minimize or completely eliminate the formation of such impurities", explains Anastasia Vornovskikh, junior researcher at the Advanced Ceramic Materials REC, Polytechnic Institute of Far Eastern Federal University. Thanks to the SPS method, the total consolidation time for RE3+:YAG optical ceramics has been reduced by a factor of 10 - 100. Due to ultrafast sintering, the nanoscale of the grain structure of ceramics sustained provided their higher transparency in comparison with coarse-grained analogs. Their physical and mechanical properties as hardness, fracture toughness, plasticity, etc., significantly improved. "In the context of the effect of carbon contamination, the team investigated all key sintering parameters such as heating rate, external pressure, temperature, and duration of sintering/post-annealing for transparency of Nd3+:YAG ceramics. We sew up a detailed sintering map to minimize the negative technological aspect. In general, in the case of suppressing carbon contaminations, the SPS technology acquires many advantages in comparison with conventional sintering technologies," says Denis Kosyanov, FEFU research team lead, director of the FEFU PI REC for Advanced Ceramic Materials Research. According to scientist, the most challenging thing turned out to be to determine the boundary parameters of the process where begins the chemical interaction of graphite impurities with the sintered material. Most of the analytical methods failed to apply due to the ultra-low content of these impurities. Only through a modern high-precision method of X-ray photoelectron spectroscopy, that is being jointly developed by the teams from FEFU, the Institute of Chemistry (FEB RAS), and the Institute for Single Crystals (NAS of Ukraine), it became possible for the first time to record the initial stage of carbonization during SPS of optical materials, describe its nature and mechanism. As a result, an experimental high-doped 4 at% Nd3+:YAG transparent ceramics was synthesized. Its residual porosity is less than 0.02 vol%, in-line optical transmittance is about 87% of the theoretical value, microhardness of 13.2 GPa with average grain size is near 740 nm. The developers 3 times increased the level of doping of the garnet structure with neodymium ions in comparison with permissible values for the growth technologies of commercial Nd3+:YAG single crystals, preserving the nano grained structure and high mechanical characteristics of the material.
'Quantum brain' promises more eco-friendly data centers Washington DC (UPI) Feb 1, 2021 Using a new combination of materials, scientists have developed a so-called "quantum brain," a piece of computer hardware capable of physically reconfiguring itself as it processes and stores information. Like the human brain, the new hardware - described Monday in the journal Nature Nanotechnology - physically reorganizes itself as it learns. Modern computers rely on machine learning software to recognize information processing patterns and develop new strategies for storing informati ... read more
|
|
The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |