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Fabrication and application of glass spherical micro-cavity for lasing are reported. Surface-tension molding (StM) and localized-laser heating (LLH) techniques have been developed to fabricate glass super sphere, which is partially truncated spherical shape, and true spheres, respectively. Whispering gallery mode (WGM) resonances or laser oscillations from the spherical glasses were demonstrated. Super-spherical glasses possessed WGM resonances on its equatorial plane. The equatorial plane with high roundness (>0.99) serves a high quality factor to lead laser oscillation. LLH technique enables us to fabricate true spheres on a transparent substrate. Tellurite glass spheres prepared by the LLH technique showed laser oscillation with few-mW-order thresholds by direct pumping. StM and LLH technique are very suitable for both preparation and utilization of glass spheres for optical micro-cavity.

Freestanding ultrathin glass film (UGF) of 45S5 bioglass was successfully bonded on a Ti substrate by the room‐temperature bonding method. 45S5 UGFs with a thickness of 1~4 μm were fabricated by the glass‐blowing technique, and the UGF was attached on the Ti plate at room temperature with a water layer between them. The bonding strength was about 370 mJ/m2 just after bonding, and it increased during storing in the ambient atmosphere at room temperature and reached about 900 mJ/m2 after 9 hours storage. The interfaces of the UGF and Ti substrate during the bonding process were analyzed by an X‐ray photoelectron spectroscopy. The as‐prepared UGF was found to have surface layers with a high content of Na2O and low content of SiO2, and the dissolution of Na2O‐rich component into water layer induced depolymerization and polymerization of SiO2 network to form Si‐O‐Si bonds between the UGF and Ti plate and then to increase the bonding strength during storage. This work presents the simple technique to laminate the bioactive glass layer on the surface of the metal without post heat treatment. [ABSTRACT FROM AUTHOR]

Surface structures of iron-phosphate glasses were examined using X-ray photoelectron spectroscopy ( XPS). Cr2O3, CoO, and Al2O3 were introduced to the glass by the replacement of a part of Fe2O3, and the simulated fission products are also added. The obtained glasses showed high chemical durabilities by MCC-1 test. In situ high-temperature and room-temperature XPS measurements were conducted on the polished sample surfaces and also those after 1-week chemical durability test. Unique trends were observed in XPS spectra on heating and after the chemical durability test, respectively. Nature of the glass surface of iron-phosphate glasses was explained from the point of view of surface energy, and the origin of high chemical durability and the effect of chromium ions were discussed based on the changes on surface composition and valence states of transition-metal ions. [ABSTRACT FROM AUTHOR]

A Cu 2 O film is prepared on a flexible polyethylene terephthalate substrate for a bending sensor using the spin-spray method, a facile and low-environmental-load solution process. The Cu 2 O bending sensor shows high sensitivity and high resolution not only over a wide range of curvatures (0 < κ < 0.21 mm -1 ) but also for very small curvature changes (Δκ = ∼ 0.03 mm -1 ). The bending response of the sensor exhibited a curvature change of high linearity with a good gauge factor (18.2) owing to the grain-boundary resistance and piezoresistive effects of the fabricated Cu 2 O film. In addition, the sensor possesses good repeatability, stability, and long-term (>30 days) and mechanical fatigue durability (1000 bending-release cycles). The sensor is capable of detailed monitoring of large- and small-scale human motions, such as finger bending, wrist bending, nodding, mouth opening/closing, and swallowing. In addition, excellent stability and repeatability of the monitoring performance is observed over a wide range of motion angles and speeds. All of these results demonstrate the potential of the flexible bending sensor based on the Cu 2 O film as a candidate for healthcare monitoring and wearable electronics., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

A high-power continuous-wave (CW) laser was used to move a steel microsphere through a CaO-Al 2 O 3 -SiO 2 glass block at room temperature along a trajectory toward the laser source. A compositional analysis revealed that the CaO concentration in the glass decreased at the center of the microsphere's trajectory but increased in the area adjacent to it; the SiO 2 concentration showed an opposite trend while the Al 2 O 3 concentration did not change. Further, the compositional difference between the center and the area adjacent to the microsphere trajectory depends on the velocity of the microsphere, which is controllable by tuning the laser power.