scholarly journals Chiral Optical Tamm States: Temporal Coupled-Mode Theory

2017 ◽  
Author(s):  
Ivan V. Timofeev ◽  
Pavel S. Pankin ◽  
Stepan Ya. Vetrov ◽  
Vasily G. Arkhipkin ◽  
Wei Lee ◽  
...  
Keyword(s):  
Mode Coupling ◽  
Cholesteric Liquid Crystal ◽  
Stop Band ◽  
Polarized Light ◽  
Coupled Mode Theory ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Mode Theory ◽  
Coupled Mode ◽  
Localized State

The chiral optical Tamm state (COTS) is a special localized state at the interface of a handedness-preserving mirror and a structurally chiral medium such as a cholesteric liquid crystal or a chiral sculptured thin film. The spectral behavior of COTS, observed as reflection resonances, is described by the temporal coupled-mode theory. Mode coupling is different for two circular light polarizations because COTS has a helix structure replicating that of the cholesteric. The mode coupling for co-handed circularly polarized light exponentially attenuates with the cholesteric layer thickness since the COTS frequency falls into the stop band. Cross-handed circularly polarized light freely goes through the cholesteric layer and can excite COTS when reflected from the handedness-preserving mirror. The coupling in this case is proportional to anisotropy of the cholesteric and theoretically it is only anisotropy of magnetic permittivity that can ultimately cancel this coupling. These two couplings being equal results in a polarization crossover (the Kopp--Genack effect) for which a linear polarization is optimal to excite COTS. The corresponding cholesteric thickness and scattering matrix for COTS are generally described by simple expressions.

scholarly journals Circularly polarized reflection from the scarab beetle Chalcothea smaragdina : light scattering by a dual photonic structure

2017 ◽  
Vol 7 (4) ◽  
pp. 20160129 ◽  
Author(s):  
Luke T. McDonald ◽  
Ewan D. Finlayson ◽  
Bodo D. Wilts ◽  
Pete Vukusic
Keyword(s):  
Cholesteric Liquid Crystal ◽  
Polarized Light ◽  
Optical Scattering ◽  
Stratified Medium ◽  
Selective Reflection ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Electromagnetic Simulations ◽  
Left Handed ◽  
Colour Appearance

Helicoidal architectures comprising various polysaccharides, such as chitin and cellulose, have been reported in biological systems. In some cases, these architectures exhibit stunning optical properties analogous to ordered cholesteric liquid crystal phases. In this work, we characterize the circularly polarized reflectance and optical scattering from the cuticle of the beetle Chalcothea smaragdina (Coleoptera: Scarabaeidae: Cetoniinae) using optical experiments, simulations and structural analysis. The selective reflection of left-handed circularly polarized light is attributed to a Bouligand-type helicoidal morphology within the beetle's exocuticle. Using electron microscopy to inform electromagnetic simulations of this anisotropic stratified medium, the inextricable connection between the colour appearance of C. smaragdina and the periodicity of its helicoidal rotation is shown. A close agreement between the model and the measured reflectance spectra is obtained. In addition, the elytral surface of C. smaragdina possesses a blazed diffraction grating-like surface structure, which affects the diffuse appearance of the beetle's reflected colour, and therefore potentially enhances crypsis among the dense foliage of its rainforest habitat.

Complete leaky mode coupling in dual-core photonic crystal fibre based on the coupled-mode theory

2011 ◽  
Vol 20 (6) ◽  
pp. 064101
Author(s):  
Jin-Hui Yuan ◽  
Chong-Xiu Yu ◽  
Xin-Zhu Sang ◽  
Jin-Long Zhang ◽  
Gui-Yao Zhou ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Mode Coupling ◽  
Leaky Mode ◽  
Coupled Mode Theory ◽  
Photonic Crystal Fibre ◽  
Mode Theory ◽  
Coupled Mode ◽  
Dual Core

Differential polarization imaging of sickled cells

1988 ◽  
Vol 46 ◽  
pp. 62-63
Author(s):  
Marcos F. Maestre
Keyword(s):  
Optical Properties ◽  
Theoretical Approach ◽  
Polarized Light ◽  
Polarization Microscopy ◽  
Spectroscopic Techniques ◽  
Polarization Imaging ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Microscopic Scale ◽  
Chiral Structures

Recently we have developed a form of polarization microscopy that forms images using optical properties that have previously been limited to macroscopic samples. This has given us a new window into the distribution of structure on a microscopic scale. We have coined the name differential polarization microscopy to identify the images obtained that are due to certain polarization dependent effects. Differential polarization microscopy has its origins in various spectroscopic techniques that have been used to study longer range structures in solution as well as solids. The differential scattering of circularly polarized light has been shown to be dependent on the long range chiral order, both theoretically and experimentally. The same theoretical approach was used to show that images due to differential scattering of circularly polarized light will give images dependent on chiral structures. With large helices (greater than the wavelength of light) the pitch and radius of the helix could be measured directly from these images.

Blue Circularly Polarized Luminescent Amorphous Molecules with Single-handed Propeller Chirality Induced by Circularly Polarized Light Irradiation

2021 ◽  
Author(s):  
Zhaoming Zhang ◽  
Takunori Harada ◽  
Adriana Pietropaolo ◽  
Yuting Wang ◽  
Yue Wang ◽  
...  
Keyword(s):  
Polarized Light ◽  
Light Irradiation ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Trigonal Symmetry ◽  
Circularly Polarized Luminescence ◽  
Polarized Luminescence

Preferred-handed propeller conformation was induced by circularly polarized light irradiation to three amorphous molecules with trigonal symmetry, and the molecules with induced chirality efficiently exhibited blue circularly polarized luminescence. In...

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