Sensitivity versus polarisation in multilayer optical thin film design

The design of a polarised optical filter is more complicated than that of a filter where the polarisation effect does not exist (at a normal angle of incidence). An error in the optical parameters, such as the physical thickness or refractive index of a layer, results in a change in the spectral...

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Main Authors: Efrem Ejigu, Beartys Lacquet
Format: Article
Language:English
Published: Academy of Science of South Africa 2012-07-01
Series:South African Journal of Science
Subjects:
Online Access:https://www.sajs.co.za/article/view/9809
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author Efrem Ejigu
Beartys Lacquet
author_facet Efrem Ejigu
Beartys Lacquet
author_sort Efrem Ejigu
collection DOAJ
description The design of a polarised optical filter is more complicated than that of a filter where the polarisation effect does not exist (at a normal angle of incidence). An error in the optical parameters, such as the physical thickness or refractive index of a layer, results in a change in the spectral performance of the multilayer structure. The correlation between error sensitivity and the polarisation effect of light in structures designed at an oblique angle was investigated. To illustrate the correlation, a perpendicular (S) and parallel (P) polarised beam splitter, at 0.9818 µm central wavelength, designed by genetic algorithm, was used. The beam splitter changes its state of polarisation according to the error in thickness simultaneously induced in each of the layers. The error was calculated by optimising the original design. The observation of the change of the state of polarisation as a result of error sensitivity leads to a different method of designing pure S-polarised or P-polarised optical filters.
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spelling doaj.art-c61a69a493424cdd994e9c69304aea392022-12-21T20:32:06ZengAcademy of Science of South AfricaSouth African Journal of Science1996-74892012-07-011087/8Sensitivity versus polarisation in multilayer optical thin film designEfrem Ejigu0Beartys Lacquet1Department of Electrical and Electronics Engineering Science, University of Johannesburg, JohannesburgFaculty of Engineering and the Built Environment, University of the Witwatersrand, JohannesburgThe design of a polarised optical filter is more complicated than that of a filter where the polarisation effect does not exist (at a normal angle of incidence). An error in the optical parameters, such as the physical thickness or refractive index of a layer, results in a change in the spectral performance of the multilayer structure. The correlation between error sensitivity and the polarisation effect of light in structures designed at an oblique angle was investigated. To illustrate the correlation, a perpendicular (S) and parallel (P) polarised beam splitter, at 0.9818 µm central wavelength, designed by genetic algorithm, was used. The beam splitter changes its state of polarisation according to the error in thickness simultaneously induced in each of the layers. The error was calculated by optimising the original design. The observation of the change of the state of polarisation as a result of error sensitivity leads to a different method of designing pure S-polarised or P-polarised optical filters.https://www.sajs.co.za/article/view/9809SensitivityS and P-polarisationerrorgenetic algorithmoptimisation
spellingShingle Efrem Ejigu
Beartys Lacquet
Sensitivity versus polarisation in multilayer optical thin film design
South African Journal of Science
Sensitivity
S and P-polarisation
error
genetic algorithm
optimisation
title Sensitivity versus polarisation in multilayer optical thin film design
title_full Sensitivity versus polarisation in multilayer optical thin film design
title_fullStr Sensitivity versus polarisation in multilayer optical thin film design
title_full_unstemmed Sensitivity versus polarisation in multilayer optical thin film design
title_short Sensitivity versus polarisation in multilayer optical thin film design
title_sort sensitivity versus polarisation in multilayer optical thin film design
topic Sensitivity
S and P-polarisation
error
genetic algorithm
optimisation
url https://www.sajs.co.za/article/view/9809
work_keys_str_mv AT efremejigu sensitivityversuspolarisationinmultilayeropticalthinfilmdesign
AT beartyslacquet sensitivityversuspolarisationinmultilayeropticalthinfilmdesign