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Currently, the smart photonic materials that can switch circularly polarized signals in real-time have attracted extensive attention due to numerous potential applications in information storage and photonics displays. However, the dynamically reversible switching of circularly polarized signals requires precise structural reconfiguration, which is rarely achieved in traditional biomaterials. Herein, a dual photonic bandgap (PBG) structure is constructed based on the optical propagation principle of cellulose-based photonic crystals, enabling the flexible switching of the intensity, wavelength, and direction of circularly polarized luminescence (CPL). By adjusting the fluorescence intensity and the matching degree of chiral structure, the asymmetric factor value of dual PBG structure is up to -1.47, far exceeding other cellulose-based materials. Importantly, it is demonstrated that dual CPL emission can be efficiently induced by two different PBGs, opening a new approach for on-demand switching of single and dual CPL emission. In addition, the dual PBG structure exhibits dual circularly polarized reflected signals under the circular polarizer, which perfectly embodies the applicability of multiple encryptions in QR codes. This work provides new insights into the real-time manipulation of circularly polarized signals by chiral photonic materials., (© 2022 Wiley-VCH GmbH.)

A facile approach for possible industrial production of long-persistent phosphorescence, continuing to emitting light for a long time period, smart cobbles were developed toward photoluminescent hard surfaces. The inorganic strontium aluminium oxide pigment doped with rare earth elements was added to a synthetic organic epoxy in the presence of polyamine as a hardener to make a phosphor-loaded viscous fluid that can then be hardened in a few minutes. The transparency of the solid cobbles can be accomplished easily using homogeneous dispersion of the phosphor in the epoxy resin fluid before the addition of a hardener to avoid pigment aggregation. This pigment-epoxy formula can be easily applied industrially onto flagstones surfaces under ambient conditions. The photoluminescent cobblestones demonstrated an optimum excitation wavelength at 366 nm and an emission band at 521 nm with a long-persistent phosphorescence cobble surface. The development of a translucent white colour under normal daylight, bright green under ultraviolet (UV) irradiation, bright white colour after 30 sec in the dark, and phosphorescent green colour after 75 min in the dark was indicated using Commission Internationale de l'Eclairage (CIE) Laboratory coloration measurements. The luminescent hard composite cobble exhibited a highly durable and reversible long-persistent phosphorescence light. Photoluminescence, morphological, and hardness properties as well as the elemental composition of the prepared cobbles were explored., (© 2019 John Wiley & Sons, Ltd.)

Although luminescence of water lower in energy than the Cerenkov-light threshold during proton and carbon-ion irradiation has been found, the phenomenon has not yet been implemented for Monte Carlo simulations. The results provided by the simulations lead to misunderstandings of the physical phenomenon in optical imaging of water during proton and carbon-ion irradiation. To solve the problems, as well as to clarify the light production of the luminescence of water, we modified a Monte Carlo simulation code to include the light production from the luminescence of water and compared them with the experimental results of luminescence imaging of water. We used GEANT4 for the simulation of emitted light from water during proton and carbon-ion irradiation. We used the light production from the luminescence of water using the scintillation process in GEANT4 while those of Cerenkov light from the secondary electrons and prompt gamma photons in water were also included in the simulation. The modified simulation results showed similar depth profiles to those of the measured data for both proton and carbon-ion. When the light production of 0.1 photons/MeV was used for the luminescence of water in the simulation, the simulated depth profiles showed the best match to those of the measured results for both the proton and carbon-ion compared with those used for smaller and larger numbers of photons/MeV. We could successively obtain the simulated depth profiles that were basically the same as the experimental data by using GEANT4 when we assumed the light production by the luminescence of water. Our results confirmed that the inclusion of the luminescence of water in Monte Carlo simulation is indispensable to calculate the precise light distribution in water during irradiation of proton and carbon-ion.