The transmission of light through low-coverage regular and random arrays of glass-supported silica micropillars of diameters 10-40 µm and height 10 µm is studied experimentally. Angle-resolved measurements of the transmitted intensity are performed at visible wavelengths by either a goniospectrophotometer or a multimodal imaging (Mueller) polarimetric microscope. It is demonstrated that for the regular arrays, the angle-resolved measurements are capable of resolving many of the densely packed diffraction orders that are expected for periodic structures of lattice constants 20-80 µm, but they also display features ("halos" and fringes) that are due to the scattering and guiding of light in individual micropillars or in the supporting glass slides. These latter features are also found in angle-resolved measurements on random arrays of micropillars of the same surface coverage. Finally, we perform a comparison of direct measurements of haze in transmission for our patterned glass samples with what can be calculated from the angle-resolved transmitted intensity measurements. Good agreement between the two types of results is found, which testifies to the accuracy of the angle-resolved measurements that we report.
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http://dx.doi.org/10.1364/AO.58.009267 | DOI Listing |
Sci Adv
December 2024
Department of Materials Science and Engineering, University of Maryland, College Park, MD 20742, USA.
A fundamental requirement for photonic technologies is the ability to control the confinement and propagation of light. Widely used platforms include two-dimensional (2D) optical microcavities in which electromagnetic waves are confined in either metallic or distributed Bragg reflectors. Recently, transition metal dichalcogenides hosting tightly bound excitons with high optical quality have emerged as promising atomically thin mirrors.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
December 2024
Institut für Physik & Center for the Science of Materials Berlin (CSMB), Humboldt-Universität zu Berlin, Berlin 12489, Germany.
Isomerism of molecular structures is often encountered in the field of organic semiconductors, but little is known about how it can impact electronic and charge transport properties in thin films. This study reveals the molecular orientation, electronic structure, and intermolecular interactions of two isomeric thienoacenes (DN4T and isoDN4T) in thin films, in relation to their charge transport properties. Utilizing scanning tunneling microscopy (STM), angle-resolved photoemission spectroscopy (ARUPS), and near-edge X-ray absorption fine structure measurements (NEXAFS), we systematically analyze the behavior of these isomers from submonolayer to multilayer coverage on highly ordered pyrolytic graphite (HOPG) as substrates.
View Article and Find Full Text PDFACS Nano
December 2024
IMDEA Nanoscience, C/Faraday 9, 28049 Madrid, Spain.
The existence of superconductivity (SC) appears to be established in both twisted and nontwisted graphene multilayers. However, whether their building block, single-layer graphene (SLG), can also host SC remains an open question. Earlier theoretical works predicted that SLG could become a chiral -wave superconductor driven by electronic interactions when doped to its van Hove singularity, but questions such as whether the -wave SC survives the strong band renormalizations seen in experiments, its robustness against the source of doping, or if it will occur at any reasonable critical temperature () have remained difficult to answer, in part due to uncertainties in model parameters.
View Article and Find Full Text PDFNanophotonics
August 2024
College of Physical Science and Technology, State Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen 361005, China.
Quasi-bound states in the continuum (quasi-BICs) offer unique advantages in enhancing nonlinear optical processes and advancing the development of active optical devices. Here, the tunable robust quasi-BICs resonances are experimentally achieved through the engineering of multiple-hole Si-metasurface. Notably, the quasi-BICs mode exhibits flat bands with minimal dispersion at a wide range of incident angles, as demonstrated by the angle-resolved spectroscopy measurements.
View Article and Find Full Text PDFNat Commun
December 2024
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, Singapore.
Topological exciton-polaritons are a burgeoning class of topological photonic systems distinguished by their hybrid nature as part-light, part-matter quasiparticles. Their further control over novel valley degree of freedom (DOF) has offered considerable potential for developing active topological optical devices towards information processing. Here, employing a two-dimensional (2D) valley-Hall perovskite lattice, we report the experimental observation of valley-polarized topological exciton-polaritons and their valley-dependent propagations at room temperature.
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