Optical activity measurements in the smectic blue phases

Grelet, Éric; Collings, Peter J.; Li, Min-Hui; Nguyen, H. T.

doi:10.1007/s101890170017

Cited by 14 publications

(14 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The three-dimensional polyhedral habit of the BP Sm 2 monocrystals shown in figures 7 to 10 seems close to a rhombic dodecahedron, which has already been observed for classical cubic blue phase [3]. Nevertheless, the experimental crystallites cannot reproduce a perfect rhombic dodecahedron where r is the optical activity, l~2p/k is the wavelength of the light (k being the wavevector of the light), and l 0~n P (P being the lattice parameter and n the average refractive index) [16]. because their birefringence is incompatible with a cubic structure.…”

Section: Introductionmentioning

confidence: 75%

“…It is important to note here that the Bragg scattering is not due to the periodicity of the orientational order, which is at the length scale of the unit cell (about 200 nm, the dimension of the lattice parameter) (figure 6) [16]. Only the smectic order has been probed, defined by a periodicity of 4 nm and a correlation length of about 60 nm, three times smaller than the size of the unit cell ( figure 12).…”

Section: X-ray Scattering Experimentsmentioning

confidence: 99%

See 1 more Smart Citation

Liquid-crystalline smectic blue phases

Grelet

2003

Liquid Crystals Today

Self Cite

View full text Add to dashboard Cite

Smectic blue phases (BP Sm ) are new mesophases of thermotropic liquid crystals, which exhibit a double geometrical frustration: the extension of chirality in three spatial dimensions like the classical blue phases, and helical twist competing with smectic order, as in the TGB phases. The existence of a quasi-long range smectic order in BP Sm phases breaks the cubic symmetry of classical blue phases. The symmetries of these new phases have been determined by X-ray scattering and optical polarizing microscopy experiments.

show abstract

Section: Introductionmentioning

confidence: 75%

Section: X-ray Scattering Experimentsmentioning

confidence: 99%

Liquid-crystalline smectic blue phases

Grelet

2003

Liquid Crystals Today

Self Cite

View full text Add to dashboard Cite

show abstract

“…Contrary to the gray color of the BP Sm 2 phase coming from its birefringence, the blue color of the BP SmA 1, BP SmC 1, and BP Sm 3 phases originates from their optical activity; this can only be seen in absence of high birefringence. Moreover, the BP Sm lattice parameter is in the near UV-range, and is therefore too small to generate selective reflections of visible light [15]. The thickness of the samples is 100 microns and their vertical size is 1 mm.…”

Section: Experiments and Resultsmentioning

confidence: 99%

Liquid Crystals Exhibiting a Double Geometrical Frustration: The Smectic Blue Phases

Grelet

2004

Molecular Crystals and Liquid Crystals

Self Cite

View full text Add to dashboard Cite

Smectic blue phases (BP Sm ) are original mesophases of thermotropic liquid crystals, which exhibit both three-dimensional orientational order, such as classical blue phases, and smectic positional order. The BP Sm phases appear to be the three-dimensional counterpart of the twist grain boundary (TGB) phases. The symmetries of these new phases have been determined by X-ray scattering and optical polarizing microscopy experiments.

show abstract

“…73 The main Bragg contribution G to the SC Bloch mode is determined and the band structure unfolded plotting 1 − k and exchanging E + ↔ E − if 2πG · e k /a yields an odd number. 74 The sum over α is unnecessary in this special case as all C 4 representations are one-dimensional. 75 For any dielectric PC as shown in Ref.…”

mentioning

confidence: 99%

“…70 Simulations are performed with the commercial software package CST Microwave Studio. We used the finite-element frequency domain solver with periodic boundary conditions in the transverse plane and a 3 [4] unit cells wide slab of the 8-srs structure. Perfectly matched layers are used for the z boundaries of the simulation box.…”

mentioning

confidence: 99%

Group theory of circular-polarization effects in chiral photonic crystals with four-fold rotation axes applied to the eight-fold intergrowth of gyroid nets

et al. 2013

View full text Add to dashboard Cite

We use group or representation theory and scattering matrix calculations to derive analytical results for the band structure topology and the scattering parameters, applicable to any chiral photonic crystal with bodycentered-cubic symmetry I 432 for circularly polarized incident light. We demonstrate in particular that all bands along the cubic [100] direction can be identified with the irreducible representations E ± , A, and B of the C 4 point group. E + and E − modes represent the only transmission channels for plane waves with wave vector along the line, and E − and E + are identified as noninteracting transmission channels for right-and left-circularly polarized light, respectively. Scattering matrix calculations provide explicit relationships for the transmission and reflectance amplitudes through a finite slab which guarantee equal transmission rates for both polarizations and vanishing ellipticity below a critical frequency, yet allowing for finite rotation of the polarization plane. All results are verified numerically for the so-called 8-srs geometry, consisting of eight interwoven equal-handed dielectric gyroid networks embedded in air. The combination of vanishing losses, vanishing ellipticity, near-perfect transmission, and optical activity comparable to that of metallic metamaterials makes this geometry an attractive design for nanofabricated photonic materials. Optical properties, such as optical rotation or circular dichroism, that are caused by a chiral structure of a lighttransmitting medium or of its constituent molecules, remain of great interest in many different contexts. Circular dichroism spectroscopy of optically active molecules in solution is used in biochemistry where left-handed (LH) and right-handed (RH) molecular architectures cause different absorption properties for left-circularly polarized (LCP) and right-circularly polarized (RCP) light. 1 Optical activity of natural crystals such as quartz (see, e.g., Ref.2) and of liquid crystals, both in the twisted nematic 3 and the blue phases, 4,5 is well known. Circularly polarized (CP) reflections of insect cuticles were observed by Michelson a century ago, 6 with circular-polarization effects an active topic in biophotonics of beetles, 7,8 crustaceans, 9,10 and butterflies, 11 and also the plant kingdom. 12 Nanofabrication technology nowadays allows for the fabrication of custom-designed chiral materials, both dielectric photonic crystals 13-15 and metallic metamaterials, [16][17][18] with the potential for technological photonic devices. This ability to fabricate custom-designed structures has led to noteworthy chiral-optical behavior, including strong circular dichroism, 19 negative refractive index 20 based on Pendry's prediction, 21 optically induced torque, 22 handedness switching in metamolecules, 23 and circular-polarized beam splitting. 15 Metallic or plasmonic metamaterials have been designed to give strong optical activity 16,18,24,25 that is orders of magnitudes stronger than in the natural materials.This article makes a tw...

show abstract

Optical activity measurements in the smectic blue phases

Cited by 14 publications

References 18 publications

Liquid-crystalline smectic blue phases

Liquid-crystalline smectic blue phases

Liquid Crystals Exhibiting a Double Geometrical Frustration: The Smectic Blue Phases

Group theory of circular-polarization effects in chiral photonic crystals with four-fold rotation axes applied to the eight-fold intergrowth of gyroid nets

Contact Info

Product

Resources

About