Ellipsometry on Anisotropic Materials: Bragg Conditions and Phonons in Dielectric Helical Thin Films

Schubert, M.; Herzinger, C. M.

doi:10.1002/1521-396x(200112)188:4<1563::aid-pssa1563>3.0.co;2-8

Cited by 37 publications

(17 citation statements)

References 46 publications

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“…It has been shown theoretically that the CBP is also exhibited for oblique incidence by cholesteric LCs [27], chiral smectic LCs [28,29], chiral STFs [30,31], and Reusch piles [32]. Additional spectral regimes of high reflectance can appear for oblique incidence, but are generally much weaker [27,30,33] and do not appear to be of technological importance.…”

Section: Introductionsupporting

confidence: 90%

Experimental investigation of circular Bragg phenomenon for oblique incidence

2015

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A 20-period-thick chiral sculptured thin film (STF) of zinc selenide was fabricated on a glass slide by thermal evaporation. A variable-angle spectroscopic system was devised and used to measure all eight of the circular remittances of the chiral STF as functions of the angle of incidence and the free-space wavelength. Thereby, the center wavelength and the bandwidth of the circular Bragg phenomenon exhibited by structurally chiral materials such as cholesteric liquid crystals and chiral STFs were comprehensively characterized for incidence angles in the range [0°,70°]. The experimental data were qualitatively compared with data calculated using a helicoidal model for the relative permittivity dyadic of the chiral STF, and assuming that all three eigenvalues of that dyadic obey the single-resonance Lorentz model. The chosen representation was found adequate to represent the blue shift of the centerwavelength with an increasing angle of incidence, but the Lorentz model requires modification to develop improved predictive capabilities.

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Section: Introductionsupporting

confidence: 90%

Experimental investigation of circular Bragg phenomenon for oblique incidence

2015

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“…A detailed discussion can be found elsewhere. 30,35 The major optical constants ͑n j + ͱ −1k j ͒ϵ ͱ ͑1+ j ͒͑j = a , b , c͒ can thus be extracted on a point-by-point basis, i.e., without any physical lineshape implementations. Kramers-Kronig consistency tests can then be done individually for dielectric functions along each axis.…”

Section: ͑2͒mentioning

confidence: 99%

Optical, structural, and magnetic properties of cobalt nanostructure thin films

Schmidt

Kjerstad

Hofmann

et al. 2009

Journal of Applied Physics

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We report on optical, structural, and magnetic properties of two substantially different cobalt nanostructure thin films deposited at an oblique angle of incidence of 85°away from the substrate normal. Comparison is made between an achiral columnar thin film grown without substrate rotation and a chiral nanocoil sculptured thin film by glancing angle deposition with substrate rotation. Generalized spectroscopic ellipsometry is employed to determine geometrical structure properties and the anisotropic optical constants of the films in the spectral range from 400 to 1000 nm. The magnetic properties are analyzed with a superconducting quantum interference device magnetometer. Both nanostructure thin films show highly anisotropic optical properties such as strong form birefringence and large dichroism. In particular, Co slanted columnar thin films are found to possess monoclinic optical properties. Magnetic measurements at room temperature show hysteresis anisotropy with respect to a magnetic field either parallel or perpendicular to the nanostructures' long axis. We find extremely large coercive fields of approximately 3 kOe for our achiral columnar nanostructures.

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“…The polarization phenomenon can be seen to shift slightly towards shorter wavelengths (blue shift) with increasing θ . This is consistent with the behavior of optical properties of chiral sculptured thin films as found by simulations [6,23] and experimental investigations [13]. The transformation of the polarization state upon reflection seems to be almost independent of the azimuth angle ϕ for the two chiral films investigated.…”

Section: Left Handedmentioning

confidence: 99%

Chiral nanostructures producing near circular polarization

Magnusson¹,

Hsiao²,

Birch³

et al. 2014

Opt. Mater. Express

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Abstract:Optical properties of chiral nanostructured films made of Al 1−x In x N using a new growth mechanism -curved-lattice epitaxial growth -are reported. Using this technique, chiral films with rightand left-handed nanospirals were produced. The chiral properties of the films, originating mainly from an internal anisotropy and to a lesser extent from the external helical shape of the nanospirals, give rise to selective reflection of circular polarization which makes them useful as narrow-band near-circular polarization reflectors. The chiral nanostructured films reflect light with high degree of circular polarization in the ultraviolet part of the spectrum with left-and right-handedness depending on the handedness of the nanostructures in the films.

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Ellipsometry on Anisotropic Materials: Bragg Conditions and Phonons in Dielectric Helical Thin Films

Cited by 37 publications

References 46 publications

Experimental investigation of circular Bragg phenomenon for oblique incidence

Experimental investigation of circular Bragg phenomenon for oblique incidence

Optical, structural, and magnetic properties of cobalt nanostructure thin films

Chiral nanostructures producing near circular polarization

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