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Related papers: Chiral Sculptured Thin Films for Circular Polariza…

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The relative permittivity dyadic of a dielectric structurally chiral material (SCM) varies helicoidally along a fixed direction; in consequence, the SCM exhibits the circular Bragg phenomenon, which is the circular-polarization-selective…

Optics · Physics 2014-03-03 Akhlesh Lakhtakia

Wavefront shaping has revolutionized imaging deep in scattering media, being able to spatially and temporally refocus light through or inside the medium. However, wavefront shaping is not compatible yet with polarization-resolved microscopy…

Optics · Physics 2018-11-26 Hilton B. de Aguiar , Sylvain Gigan , Sophie Brasselet

A theoretical study of Bragg diffraction by an enantiomorphic pair of structures should apply to patterns gathered on beta-Mn using resonance enhanced x-ray diffraction. The chiral polymorph of manganese, and structurally related compounds,…

Materials Science · Physics 2021-04-28 S. W. Lovesey

We studied the durations and average speeds of videopulses transmitted through chiral sculptured thin films using a finite-difference algorithm. The chiral STF was either linear or possessed an intensity-dependent permittivity. Videopulse…

Optics · Physics 2007-05-23 Joseph B. Geddes , Akhlesh Lakhtakia

Periodically patterned columnar thin films (PP-CTFs) were made by evaporating CaF2 and directing the vapor flux obliquely towards lithographically fabricated micrometer/sub-micrometer gratings. The growth of the PP-CTFs was controlled by…

Optics · Physics 2015-06-11 Jhuma Dutta , S. Anantha Ramakrishna , Akhlesh Lakhtakia

A dielectric columnar thin film (CTF), characterized macroscopically by a relative permittivity dyadic, was investigated theoretically with the assumption that, on the nanoscale, it is an assembly of parallel, identical, elongated…

Optics · Physics 2015-05-14 Tom G. Mackay , Akhlesh Lakhtakia

The concept of local homogenization is invoked in the visible and the sub-visible frequency regimes to estimate the permittivity dyadics of a thin-film helicoidal bianisotropic mediums (TFHBMs)~---~a canonical class of sculptured thin films…

Optics · Physics 2019-10-01 Akhlesh Lakhtakia

A blazed chirped Bragg grating in a planar silica waveguide device was used to create an integrated diffractive element for a spectrometer. The grating diffracts light from a waveguide and creates a wavelength dependent focus in a manner…

Developments that took place in the area of sculptured--thin--film technology after {\em Bianisotropics '98\/} are reviewed here. Devices addressed include: optical filters of various kinds, laser mirrors, gas--concentration sensors,…

Optics · Physics 2014-06-09 Akhlesh Lakhtakia

Tunable light filters are critical components for many optical applications in which light in-coupling, out-coupling or rejection is crucial, such as lasing, sensing, photovoltaics and information and communication technology. For this…

Optics · Physics 2014-07-17 Ilka Kriegel , Francesco Scotognella

Friedel's law guarantees an inversion-symmetric diffraction pattern for thin, light materials where a kinematic approximation or a single-scattering model holds. Typically, breaking Friedel symmetry is ascribed to multiple scattering events…

Phonon polaritons are known to emerge at the surfaces of solids under IR irradiation at frequencies close to the optical phonon resonance. Metal, patterned on the top of the polariton-active surface, locally blocks the excitation of the…

The behavior of electromagnetic waves in chirally twisted structures is a topic of enduring interest, dating back at least to the invention in the 1940s of the microwave travelling wave tube amplifier and culminating in contemporary studies…

Optics · Physics 2021-04-07 Yang Chen , Philip St. J. Russell

We present the first experimental results on the use of a thick aligned Si crystal acting as a quarter wave plate to induce a degree of circular polarisation in a high energy linearly polarised photon beam. The linearly polarised photon…

We report a series of experimental, analytical and numerical studies demonstrating strong circular dichroism in helically twisted hollow-core single-ring photonic crystal fiber (SR-PCF), formed by spinning the preform during fiber drawing.…

Surface waves, named here as Dyakonov-Tamm waves, can exist at the planar interface of an isotropic dielectric material and a chiral sculptured thin film (STF). Due to the periodic nonhomogeneity of a chiral STF, the range of the refractive…

Optics · Physics 2007-07-24 Akhlesh Lakhtakia , John A. Polo

Optical second-harmonic generation (SHG) is studied for the confined geometry of a circular cylindrical waveguide or optical fiber. A model situation of high symmetry is considered where the material with nonlinear susceptibility is…

Optics · Physics 2013-09-17 B. U. Felderhof , G. Marowsky

Electron diffraction through a thin patterned silicon membrane can be used to create complex spatial modulations in electron distributions by varying the intensity of different reflections using parameters such as crystallographic…

Accelerator Physics · Physics 2019-05-30 L. E. Malin , W. S. Graves , M. Holl , J. C. H. Spence , E. A. Nanni , R. K. Li , X. Shen , S. Weathersby

Four crystal classes are optically active yet not chiral (non-enantiomorphic). Corresponding Bragg diffraction patterns calculated for circularly polarized (helical) x-rays tuned to an atomic resonance prove that angular anisotropy in the…

Strongly Correlated Electrons · Physics 2021-12-15 Stephen W. Lovesey

Empirical potential structure refinement (EPSR) simulations are performed on total neutron scattering data from powder samples of polytetrafluoroethylene (PTFE) and polychlorotrifluoroethylene (PCTFE), both at 300K. For PTFE a number of…

Soft Condensed Matter · Physics 2013-09-27 A K Soper , K Page , A Llobet