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DArk Matter Particle Explorer (DAMPE), a satel- lite-based cosmic-ray (CR) and gamma-ray measurement experiment, relies on its calorimeter to measure the energy of incident particles. The calorimeter adopts crystals of bismuth germanium oxide (BGO) as scintillating material, and it is designed to aim for measurements of energy ranging from 50 GeV to 100 TeV in the case of a CR nucleus. This article concerns the response of the BGO calorimeter to nucleus-type CRs. CRs with very low energy can rarely reach the detector due to the Earth’s magnetic field. A cutoff on lower energy can be observed in the energy spectrum. In this article, the cutoff is used to study the response of the calorimeter. Carbon, neon, silicon, and iron are analyzed separately in comparison with Monte Carlo simulations by Geant4. [ABSTRACT FROM AUTHOR]

In this paper, magnetically tunable random lasing from a polymer dispersed liquid crystal (PDLC) in a capillary was achieved by means of doping with magnetic nanoparticles (MNPs). We experimentally explored the effects of the concentration of MNPs and the amplitude and direction of the magnetic field on the emission properties of random lasing, such as threshold, envelope of the emission spectrum, and intensities. The related mechanism was also investigated theoretically. Experimental results also showed that weakly tuned effects appeared from the sample with a polymer or pure liquid crystal (LC) doped with MNPs in comparison with PDLCs. Our research would provide an additional way to achieve tunable compact LC-based lasers. [ABSTRACT FROM AUTHOR]

Temperature dependent lasing was demonstrated in a dye-doped two-dimensional hexagonal photonic crystal made of holographic polymer-dispersed liquid crystals (LCs) along ΓM direction in TE polarization. A redshift in lasing peaks was observed as the temperature increased from 25 to 45 °C. The downward movement of photonic band of TE polarization, majorly caused by the decrease in the anisotropy of LC droplets with the increase in temperature, is responsible for the redshift in lasing peaks. [ABSTRACT FROM AUTHOR]

The growing demand for flexible low-power reflective photonics and display devices has fueled research into high quality flexible materials with super-reflectivity and high stability to environmental influences including broad working temperature ranges and excellent mechanical stress insensitivity. Although tremendous effort has been dedicated towards developing cholesteric film materials with super-reflectivity or high stability, challenges still remain in achieving both due to the existence of liquid crystals that are susceptible and sensitive to external stimuli, such as temperature or mechanical stress. Herein, we fabricate a novel flexible film having super-reflectivity (＞80%), a broad working temperature range (−70 °C to 70 °C) and excellent mechanical stress insensitivity (up to 7.88 × 105 Pa) via a “washout–refill–assemble” approach by refilling a polymer (optical adhesive) into a cholesteric film assembled using two cholesteric templates with opposite handedness based on a liquid crystal/reactive mesogen mixture, where no liquid crystals exist in the final fabricated multi-layer film. The all-polymer structure of the film selectively reflects color due to the helical structure of the cholesteric liquid crystals applied in the fabrication procedure of the cholesteric templates with both super-reflectivity and high stability to temperature and mechanical stress. Flexible displays with vivid colors based on proposed films have been demonstrated using the direct printing method on glass and flexible substrates. These materials show great potential for applications such as low-power flexible reflective displays, and other photonic flexible devices including lasers, smart windows, color pixels in digital photographs, and colored cladding of a variety of objects. [ABSTRACT FROM AUTHOR]

We propose to use a 1-atom-thick structure, i.e., a single graphene sheet for the dynamic control of an Airy plasmon (AiP). The graphene layer serves not only as the guiding medium but also as the modulator for the AiP. By altering the external biased voltage, the effective mode index for surface plasmon waves can be modified. Consequently, the deflection and the propagation distance of the AiP are controlled dynamically. Due to the advantages of graphene plasmons, graphene AiPs may lead to compact and flexible AiP devices. This paper could be also beneficial to relevant applications such as tunable plasmonic optical routing and on-chip signal processing. [ABSTRACT FROM PUBLISHER]

Surface-morphology evolution of ZnO nanocrystals has been observed by the hydrothermal process. The effects of stirring time and ammonia content on the morphology evolution have been discussed, respectively. Extension of stirring time of the precursor results in morphology transformation from star-like to wire-like ZnO nanocrystals. ZnO nuclei aggregation and uniform Zn(OH)2 precipitation can readily explain these two morphologies, respectively. By increasing the ammonia content in the solution, the morphology of ZnO crystals is transformed from an irregular shape to hexagon sheets to nanorods, and the side length of ZnO crystals is decreased accordingly. Hollow structures are realized at the subsequent solution aging process. Variation of zinc ammonic complex and minimum surface energy can well explain the morphology evolution of ZnO nanostructures. [ABSTRACT FROM AUTHOR]

Mode-dependent electrically tunable lasing of transverse electric (TE) and transverse magnetic (TM) modes is demonstrated in a dye-doped two-dimensional hexagonal photonic crystal made of holographic polymer-dispersed liquid crystals (LCs). Over 10 nm redshifting in lasing with multiple peaks in nonpolarizing spectra is obtained by applying external voltages up to 40 V. The splitting of lasing spectra between two perpendicular polarizations with the applied voltage is observed, which can be explained through the difference in effective refractive index of LC droplet change with the applied electric field for TE and TM modes. [ABSTRACT FROM AUTHOR]

Lasing actions are demonstrated in two high-symmetry directions (ΓM and ΓK) of a two-dimensional hexagonal photonic crystal from dye-doped holographic polymer-dispersed liquid crystals. The group velocity anomaly, which is peculiar to two-dimensional and three-dimensional photonic crystals, leads to substantial enhancement in local fields in the two-dimensional photonic crystal with a low-index contrast. The difference on the lasing thresholds between the two directions is interpreted as the result of different group velocities of the flat bands where laser oscillation occurred. [ABSTRACT FROM AUTHOR]

A polarization insensitive 2×2 optical switch was fabricated with liquid crystal–polymer composite by means of holography. The highest diffraction efficiency achieved was 85.7%. The rise time and the decay time measured were 36 and 160 μs, respectively, at an applied electric field of 18.2 V/μm. The polarization-dependent loss was 0.03 dB measured for s- and p-polarized light at the wavelength of 632.8 nm. [ABSTRACT FROM AUTHOR]