Polycrystalline textured thin films with distinct pleochroism and birefringence comprising oriented rotational domains of the orthorhombic polymorph of an anilino squaraine with isobutyl side chains (SQIB) are analyzed by imaging Mueller matrix ellipsometry to obtain the biaxial dielectric tensor. Simultaneous fitting of transmission and oblique incidence reflection Mueller matrix scans combined with the spatial resolution of an optical microscope allows to accurately determine the full biaxial dielectric tensor from a single crystallographic sample orientation. Oscillator dispersion relations model well the dielectric tensor components. Strong intermolecular interactions cause the real permittivity for all three directions to become strongly negative near the excitonic resonances, which is appealing for nanophotonic applications.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8041376 | PMC |
| http://dx.doi.org/10.1021/acs.jpclett.1c00317 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Recently, there has been an explosion of activity in the fields of optics and photonics with the advent of fabrication techniques which enable the design of metamaterials which possess properties not encountered in the natural world. In this work, we are concerned with zero permittivity materials and a new scheme to design metamaterials for which all components of the dielectric tensor are approximately zero. Our approach involves the alternate layering of many, very thin, slices of two constituent metamaterials, a uniaxial layered medium and a uniaxial nanowire array.
View Article and Find Full Text PDFRefinement of Atomic Polarizabilities for a Polarizable Gaussian Multipole Force Field with Simultaneous Considerations of Both Molecular Polarizability Tensors and In-Solution Electrostatic Potentials.
J Chem Inf Model
January 2025
Departments of Molecular Biology and Biochemistry, Chemical and Biomolecular Engineering, Materials Science and Engineering, and Biomedical Engineering, University of California, Irvine, Irvine, California 92697, United States.
Atomic polarizabilities are considered to be fundamental parameters in polarizable molecular mechanical force fields that play pivotal roles in determining model transferability across different electrostatic environments. In an earlier work, the atomic polarizabilities were obtained by fitting them to the B3LYP/aug-cc-pvtz molecular polarizability tensors of mainly small molecules. Taking advantage of the recent PCMRESPPOL method, we refine the atomic polarizabilities for condensed-phase simulations using a polarizable Gaussian Multipole (pGM) force field.
View Article and Find Full Text PDFMaterials with Negative Permittivity or Negative Permeability-Review, Electrodynamic Modelling, and Applications.
Materials (Basel)
January 2025
Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warsaw, Poland.
A review of natural materials that exhibit negative permittivity or permeability, including gaseous plasma, metals, superconductors, and ferromagnetic materials, is presented. It is shown that samples made of such materials can store large amount of the electric (magnetic) energy and create plasmonic resonators for certain values of permittivity, permeability, and dimensions. The electric and the magnetic plasmon resonances in spherical samples made of such materials are analyzed using rigorous electrodynamic methods, and the results of the analysis are compared to experimental data and to results obtained with other methods.
View Article and Find Full Text PDFElectrically Switchable Multi-Stable Topological States Enabled by Surface-Induced Frustration in Nematic Liquid Crystal Cells.
Adv Mater
January 2025
Liquid Crystals and Photonics Group, Department of Electronics and Information Systems, Ghent University, Technologiepark-Zwijnaarde 126, Ghent, 9052, Belgium.
In liquid crystal (LC) cells, the surface patterning directs the self-assembly of the uniaxial building blocks in the bulk, enabling the design of stimuli-response optical devices with various functionalities. The combination of different anchoring patterns at both substrates can lead to surface induced frustration, preventing a purely planar and defect-free configuration. In cells with crossed assembly of rotating anchoring patterns, elastic deformations allow to obtain a defect-free bulk configuration, but an electrical stimulus can induce disclination lines.
View Article and Find Full Text PDFStructural, morphological, mechanical, and electrical studies of N. nucifera fibres.
Int J Biol Macromol
December 2024
Center for Material Science, Vijnana Bhavan, Manasagangotri, University of Mysore, Mysuru 570017, India.
The Powder X-ray diffraction (PXRD) data of Nelumbo Nucifera fibre is utilized to study multifaceted properties. Rietveld refinement was carried out along with cellulose phase. The crystallite size was computed using the Scherrer equation, and through first principle calculations, it has been illustrated and concluded that the size is not ellipsoidal, as previously suggested by other researchers; rather, it exhibits a multidimensional shape.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!