RESUMO
Microscale local strain gauges with low-power consumption and large strain range were demonstrated by integrating microdisk lasers in a deformable and flexible polymer substrate. The lasing spectra of microdisk lasers were sensitive to substrate deformation and can be modulated by strains. The measured relative wavelength tuning under strains of the novel strain sensors illustrated a linear behavior with the gauge factor being ~4.0 nm and ~6.7 nm per stretching unit for microdisk lasers with the diameter of 1.2 µm and 1.5 µm, which corresponding to a smooth wavelength tuning of 1.5 nm and 2.6 nm under 36% strain, respectively. In addition, to being used as microscale strain gauges, the visible lasers on the deformable substrate can also function as a tunable light source for the photonic integrated circuits and flexible laser projection displays.
RESUMO
In this paper, we report the design, fabrication, and characterization of a tungsten-based metamaterial selective solar absorber (SSA) combining a metal-insulator-metal (MIM) structure and simple nanodisk array. The as-fabricated absorber absorbs strongly and selectively in the wavelength range of 0.5-1.75 µm with a characterized absorptance of more than 90%, which drops abruptly to less than 12.6% beyond 2.5 µm. In addition, this broadband and highly selective absorber is polarization-insensitive under incidence of normal plane waves. Moreover, the solar selectivity remains invariable up to 40°, which is beneficial for solar thermal applications. These properties are verified theoretically and experimentally in the present work. Further analysis on energy dissipation reveals the underlying physics and optical performances.
RESUMO
A flexible photonic crystal cavity, consisting of a III-V active layer embedded in a flexible medium, with a line-defect by removing three air holes for nanoscale structural deformation detection is proposed and optimized. The cavity can hold the photonic band-gap modes with the fundamental mode located at approximately 686 nm, overlapping with the photoluminescence spectrum of the InGaP/InGaAlP quantum wells. Results of finite-difference time-domain simulations indicate that the L3 cavity features an ultra-compact mode volume of 10-3 µm3 and high quality factor of 104 at a sub-micron footprint within the studied visible wavelength. Theoretical optical strain sensitivities of approximately 4.5 and 3 nm per ε (1% strain for both) for the x and y directions are predicted, respectively. When the cavity is under large bending curvatures, the Q factor rapidly decreases from 8000 to 2000.
RESUMO
In this work, visible-light-driven Znln2S4 photocatalyst (band gap 1.98 eV, absorption wavelength 300-600 nm) was synthesized by a facile hydrothermal method for photocatalytic degradation of trace pharmaceutical carbamazepine (CBZ) in aqueous solution, and characterized by UV-Vis diffusive reflectance spectroscopy, BET, SEM and XRD, respectively. It demonstrated that a complete degradation of CBZ was achieved with an optimal Znln2S4 dosage of 30 mg/L under a 100 W iodine-gallium lamp irradiation of 20 min, which afforded the reaction rate constant and half-life being respectively 10.44 times higher and 1/8 less than that obtained by a direct photolysis without Znln2S4 photocatalyst. A negligible influence of initial solution pH on photocatalytic degradation of CBZ was confirmed under the given pH range of 5.0-9.0. The degradation efficiency of CBZ was slightly decreased from 91% to 84% after five consecutive cycles. Hydroxy radical (·OH) plays an important role in CBZ degradation accompanying a synergistic effect of photogenerated hole (h+) and O2- active species during reaction. Further, 44 intermediates were detected by LCMS-IT-TOF technique and tentative degrading pathways were proposed on the basis of the experimental results.