Lasers and Electro-optics

Davis, Christophér C.

doi:10.1017/cbo9781139016629

Cited by 58 publications

(15 citation statements)

References 351 publications

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“…This condition is, therefore, always guaranteed and c(z) ¼ 1 will be safely taken in the following of this article. While this approximation was shown to be very good for an amplifying media [18], a similar demonstration was not performed, to our knowledge, for an absorbing media.…”

Section: Generation Functionmentioning

confidence: 82%

Injection in light beam induced current systems: An analytical model

Micard

Hahn

Terheiden

2016

Physica Status Solidi (a)

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In LBIC systems, the evaluation of the injection level is necessary when operating in low injection for defect recombination studies or in defined standard illumination conditions (one or several suns for concentrator applications) for quantum efficiency evaluation. We demonstrate in this contribution that evaluating the laser beam induced injection based on uniform illumination condition can lead to several decades of error because of the lateral carrier diffusion. Based on a parallel beam approximation, we propose here an analytical model to evaluate the maximum of injection of a laser with its parametrization valid for most LBIC system settings and material quality. State of the art high resolution LBIC (HR‐LBIC) systems have so sharply focused laser beams that the beam divergence cannot be neglected anymore in the injection calculation. Although providing a quantitative criterion to determine whether the beam divergence can be neglected, we provide a more advanced model for describing the injection of the laser that includes beam divergence.

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Section: Generation Functionmentioning

confidence: 82%

Injection in light beam induced current systems: An analytical model

Micard

Hahn

Terheiden

2016

Physica Status Solidi (a)

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“…Hence we discount SMHRS as a significant contributor to the nematic phase SH signal. [49] Using a description of SHG in dielectric media, incorporating intermolecular interactions, [50][51][52] collective effects [19,53] and surface interactions, [17,18] we examine the sources of the SH signal in the nematic phase. The second-order non-linear or SH polarisation P 2 ð Þ induced in such a medium by the electric field of the electromagnetic wave traversing the medium is given by [49] …”

Section: Source Of Sh Lightmentioning

confidence: 99%

Second-harmonic generation and the influence of flexoelectricity in the nematic phases of bent-core oxadiazoles

et al. 2016

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Second-harmonic generation (SHG) in the nematic phase of bent-core oxadiazole-based liquid crystals (LCs) was studied and compared to that for the rod-like compound 4-cyano-4ʹ-n-octylbiphenyl (8CB). Weak, isotropically scattered second-harmonic (SH) light was observed for all materials, consistent with SHG by nematic director fluctuations. The SH intensity produced by the bent-core materials was found to be up to~3.4 times that of 8CB. We discuss this result in terms of the dependence of SH intensity on temperature, elastic constants and flexoelectric coefficients. We have calculated the latter by using a molecular field approach with atomistic modelling, thus demonstrating how molecular parameters contribute to the flexoelectric coefficients and illustrating the potential of this method for predicting the flexoelectric behaviour of bent-core LCs. We show that the increased SH signal in the bent-core compounds is partly due to their nematic phases being at a much higher temperature, and also potentially due to them having greater flexoelectric coefficients, up to~1.5 times those of 8CB. These estimates are consistent with reports of increased flexoelectric coefficients in bent-core compounds in comparison to rod-like compounds.ARTICLE HISTORY

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“…The two basic equations taken from Ref. [2] (specifically, Equations (4.15) and (4.44) from Section 4.5 of Chapter 4) are significant for this comparison. Equation (4.15) of Ref.…”

Section: Analysis Of the Model And Its Applicability To Topography Stmentioning

confidence: 99%

“…Equation (4.15) of Ref. [2] relates the depth 'h' of the interferometer to the phase changes experienced by a plane wavefront of inclination 'h' with respect to the normal to the interferometer:…”

Section: Analysis Of the Model And Its Applicability To Topography Stmentioning

confidence: 99%

Application of Plasmons to the Determination of Surface Profile and Contact Strain Distribution

Sciammarella

Lamberti

Sciammarella

et al. 2010

Strain

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Free electrons in the surface of metals can produce surface plasmons if they are excited by evanescent waves. The surface plasmons are electromagnetic waves that by decaying can generate photons. These photons produce propagating waves that feed energy to an oscillating cavity. From this effect a Fabry–Perot like interferometer is generated. In view of this basic knowledge a truly novel application on how these plasmons can be used experimentally is introduced in this article. Essentially, by using the transformation of evanescent waves into propagating waves via the plasmon generation it is possible to perform high accuracy contouring of any metal surface as well as the determination of its contact stresses. A laser beam illuminates a glass‐air‐metal interface and through a proper optical setup it will produce double evanescent illumination. This illumination generates interference fringes that contain surface depth information as well as in‐plane strain information. In order to show the robustness of the proposed technique, three different applications are presented in the paper. First, the surface roughness mapping of a copper plate is determined and the obtained values are in statistical agreement with the data measured by a mechanical profilometer. Second, the surface profiles of nickel alloy surfaces used as calibrated standards for the determination of Ra values are obtained. The measured Ra values statistically agree with the values of the different standards. Finally, the contact strains of a copper cylinder on glass are also measured. The contact strains follow the trend predicted by the K.L. Johnson’s model of contact. Local regions (asperities) experiment large plastic deformations.

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Lasers and Electro-optics

Cited by 58 publications

References 351 publications

Injection in light beam induced current systems: An analytical model

Injection in light beam induced current systems: An analytical model

Second-harmonic generation and the influence of flexoelectricity in the nematic phases of bent-core oxadiazoles

Application of Plasmons to the Determination of Surface Profile and Contact Strain Distribution

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