S. Zollner, F. Abadizaman, C. Emminger, N. Samarasingha
Abstract The temperature dependence of the optical constants of materials (refractive index, absorption and extinction coefficients, and dielectric function) can be determined with spectroscopic ellipsometry over a broad range of temperatures and photon energies or wavelengths. Such results have practical value, for example for applications of optical materials at cryogenic or elevated temperatures. The temperature dependence of optical gaps and their broadenings also provides insight into the scattering of electrons and holes with other quasiparticles, such as phonons or magnons. This review presents a detailed discussion of the experimental considerations for temperature-dependent ellipsometry and selected results for insulators, semiconductors, and metals in the infrared to ultraviolet spectral regions.
{"title":"Spectroscopic ellipsometry from 10 to 700 K","authors":"S. Zollner, F. Abadizaman, C. Emminger, N. Samarasingha","doi":"10.1515/aot-2022-0016","DOIUrl":"https://doi.org/10.1515/aot-2022-0016","url":null,"abstract":"Abstract The temperature dependence of the optical constants of materials (refractive index, absorption and extinction coefficients, and dielectric function) can be determined with spectroscopic ellipsometry over a broad range of temperatures and photon energies or wavelengths. Such results have practical value, for example for applications of optical materials at cryogenic or elevated temperatures. The temperature dependence of optical gaps and their broadenings also provides insight into the scattering of electrons and holes with other quasiparticles, such as phonons or magnons. This review presents a detailed discussion of the experimental considerations for temperature-dependent ellipsometry and selected results for insulators, semiconductors, and metals in the infrared to ultraviolet spectral regions.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":" 21","pages":"117 - 135"},"PeriodicalIF":1.8,"publicationDate":"2022-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41254429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The Mueller matrix is a mathematical description of how light is altered by an optical element or a sample under study. It describes both intensity (irradiance) and polarization changes, including a reduction of the total polarization. Mueller matrix spectroscopic ellipsometry has gained recent popularity in the optics and semiconductor communities as an effective means to characterize complex sample structures and anisotropic materials. While this method is not new, its recent expansion to new fields has left many users with only a pedestrian understanding of the data they collect. This tutorial provides an overview of Mueller matrix spectroscopic ellipsometry with focus on practical aspects for those new to the technique.
{"title":"Mueller matrix spectroscopic ellipsometry","authors":"J. Hilfiker, N. Hong, Stefan Schoeche","doi":"10.1515/aot-2022-0008","DOIUrl":"https://doi.org/10.1515/aot-2022-0008","url":null,"abstract":"Abstract The Mueller matrix is a mathematical description of how light is altered by an optical element or a sample under study. It describes both intensity (irradiance) and polarization changes, including a reduction of the total polarization. Mueller matrix spectroscopic ellipsometry has gained recent popularity in the optics and semiconductor communities as an effective means to characterize complex sample structures and anisotropic materials. While this method is not new, its recent expansion to new fields has left many users with only a pedestrian understanding of the data they collect. This tutorial provides an overview of Mueller matrix spectroscopic ellipsometry with focus on practical aspects for those new to the technique.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":"11 1","pages":"59 - 91"},"PeriodicalIF":1.8,"publicationDate":"2022-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42140483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract This view highlights a revolutionary change in IR ellipsometry, namely, the incorporation and application of tunable lasers. The presented instrumental developments beyond classical FTIR-based approaches are coming precisely at the right time for today’s demands for in situ, operando and hyperspectral characterization methods required in bioanalytics, catalysis and surface science.
{"title":"Mid-infrared laser ellipsometry: a new era beyond FTIR","authors":"A. Furchner, K. Hinrichs","doi":"10.1515/aot-2022-0013","DOIUrl":"https://doi.org/10.1515/aot-2022-0013","url":null,"abstract":"Abstract This view highlights a revolutionary change in IR ellipsometry, namely, the incorporation and application of tunable lasers. The presented instrumental developments beyond classical FTIR-based approaches are coming precisely at the right time for today’s demands for in situ, operando and hyperspectral characterization methods required in bioanalytics, catalysis and surface science.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":"1030 ","pages":"55 - 56"},"PeriodicalIF":1.8,"publicationDate":"2022-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41275127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The crystalline lens makes an important contribution to the peripheral refraction of the human eye, which may affect the development and progression of myopia. However, little has been known about the peripheral optical features of the crystalline lens and its impacts on the peripheral ocular refraction. This study aims to investigate the relationship between the structural parameters of the crystalline lens and its peripheral power profile over a wide visual field. The peripheral power profile is defined with respect to the entrance and exit pupil centers along the chief rays. Analysis is performed by three-dimensional ray tracing through the gradient refractive index (GRIN) lens models built from measurement data. It has been found that the vergence of the wavefronts at the entrance and the exit pupil centers of the lens show an approximate linear correlation to each other for each field angle. The exponent parameters of the axial refractive index profile and the axial curvature profile, and the asphericity of the posterior lens surface are found to be the most influential parameters in the peripheral power profiles. The study also shows that there can be significantly different, sometimes unrealistic, power profiles in the homogeneous lens model compared with its corresponding GRIN model with the same external geometry. The theoretical findings on the peripheral lens properties provide a new perspective for both wide-field eye modelling and the design of intraocular lenses to achieve normal peripheral vision.
{"title":"Impacts of the gradient-index crystalline lens structure on its peripheral optical power profile","authors":"Qing Li, F. Fang","doi":"10.1515/aot-2022-0003","DOIUrl":"https://doi.org/10.1515/aot-2022-0003","url":null,"abstract":"Abstract The crystalline lens makes an important contribution to the peripheral refraction of the human eye, which may affect the development and progression of myopia. However, little has been known about the peripheral optical features of the crystalline lens and its impacts on the peripheral ocular refraction. This study aims to investigate the relationship between the structural parameters of the crystalline lens and its peripheral power profile over a wide visual field. The peripheral power profile is defined with respect to the entrance and exit pupil centers along the chief rays. Analysis is performed by three-dimensional ray tracing through the gradient refractive index (GRIN) lens models built from measurement data. It has been found that the vergence of the wavefronts at the entrance and the exit pupil centers of the lens show an approximate linear correlation to each other for each field angle. The exponent parameters of the axial refractive index profile and the axial curvature profile, and the asphericity of the posterior lens surface are found to be the most influential parameters in the peripheral power profiles. The study also shows that there can be significantly different, sometimes unrealistic, power profiles in the homogeneous lens model compared with its corresponding GRIN model with the same external geometry. The theoretical findings on the peripheral lens properties provide a new perspective for both wide-field eye modelling and the design of intraocular lenses to achieve normal peripheral vision.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":"11 1","pages":"23 - 32"},"PeriodicalIF":1.8,"publicationDate":"2022-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42496919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract The article describes the way to calculate the distances, defined by the U.S. Federal Aviation Administration in the AC 70-1B document, essential for the flight safety in the case of illumination of aircraft pilots by laser radiation. FAA’s calculations and presented examples are simplified for the most common cases of a single circular beam, or circular beams sharing the same power, divergence and aperture. Proposed in this article calculation method was extended to multi-beam radiation sources characterized by different wavelengths, different divergences in two perpendicular planes and different powers. The impact of ellipticity of the beams on the calculated distances was shown. The presented analysis may be a supplement to the AC 70-1B document and may serve as a sample approach for those who need to deal with such laser sources. Laser pointers characterized by powers of up to 50 W as well as these with typical powers of several mW were considered. It was shown that even typical 1 mW laser pointers may still distract the aircraft pilots during landing or take-off which may have adverse consequences.
{"title":"Calculation and analysis of laser hazard distances in navigable airspace for multi-beam visible CW laser radiation","authors":"J. Młyńczak","doi":"10.1515/aot-2022-0004","DOIUrl":"https://doi.org/10.1515/aot-2022-0004","url":null,"abstract":"Abstract The article describes the way to calculate the distances, defined by the U.S. Federal Aviation Administration in the AC 70-1B document, essential for the flight safety in the case of illumination of aircraft pilots by laser radiation. FAA’s calculations and presented examples are simplified for the most common cases of a single circular beam, or circular beams sharing the same power, divergence and aperture. Proposed in this article calculation method was extended to multi-beam radiation sources characterized by different wavelengths, different divergences in two perpendicular planes and different powers. The impact of ellipticity of the beams on the calculated distances was shown. The presented analysis may be a supplement to the AC 70-1B document and may serve as a sample approach for those who need to deal with such laser sources. Laser pointers characterized by powers of up to 50 W as well as these with typical powers of several mW were considered. It was shown that even typical 1 mW laser pointers may still distract the aircraft pilots during landing or take-off which may have adverse consequences.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":"11 1","pages":"33 - 46"},"PeriodicalIF":1.8,"publicationDate":"2022-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48948369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Optical encoders based on measurement of the axis-angle of linear polarizers offer high resolution and moderate accuracy, but are usually restricted to rotary measurement. We show that annular polymer sheet polarizer materials can be sheared into rectangular tapes, with a polarizing axis that varies linearly along the tape. This makes possible the construction of polarimetric linear absolute position encoders. We demonstrate also sheared polymer birefringent retarders, which function similarly, potentially with cost and size-flexibility advantages.
{"title":"Polarimetric linear absolute position encoder","authors":"Mark J. Johnson","doi":"10.1515/aot-2022-0005","DOIUrl":"https://doi.org/10.1515/aot-2022-0005","url":null,"abstract":"Abstract Optical encoders based on measurement of the axis-angle of linear polarizers offer high resolution and moderate accuracy, but are usually restricted to rotary measurement. We show that annular polymer sheet polarizer materials can be sheared into rectangular tapes, with a polarizing axis that varies linearly along the tape. This makes possible the construction of polarimetric linear absolute position encoders. We demonstrate also sheared polymer birefringent retarders, which function similarly, potentially with cost and size-flexibility advantages.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":"11 1","pages":"17 - 21"},"PeriodicalIF":1.8,"publicationDate":"2022-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46189582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Encoders of angle based on rotating polarizers suffer from 180° ambiguity due to their inherent twofold rotational symmetry. This restricts their applications in motor and machine controls. We show that the ambiguity can be resolved through a geometrical mapping from a plane to a conical surface. Seen from the local surface normal, one full rotation of the cone gives one half rotation of the polarizer axis. With appropriate transmission or reflective optics and multiphase detection, we build high resolution, moderate accuracy, absolute-angle encoders without 180° ambiguity. Polymer birefringent retarders can be used similarly.
{"title":"Polarimetric 360° absolute rotary encoder","authors":"Mark J. Johnson","doi":"10.1515/aot-2021-0056","DOIUrl":"https://doi.org/10.1515/aot-2021-0056","url":null,"abstract":"Abstract Encoders of angle based on rotating polarizers suffer from 180° ambiguity due to their inherent twofold rotational symmetry. This restricts their applications in motor and machine controls. We show that the ambiguity can be resolved through a geometrical mapping from a plane to a conical surface. Seen from the local surface normal, one full rotation of the cone gives one half rotation of the polarizer axis. With appropriate transmission or reflective optics and multiphase detection, we build high resolution, moderate accuracy, absolute-angle encoders without 180° ambiguity. Polymer birefringent retarders can be used similarly.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":"11 1","pages":"13 - 16"},"PeriodicalIF":1.8,"publicationDate":"2022-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46904221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract In this paper, we present a cornea deformation model based on the idea of extending the ‘neutral axis’ model to two-dimensional deformations. Considering this simple model, assuming the corneal tissue to behave like a continuous, isotropic and non-compressible material, we are able to partially describe, e.g., the observed deviation in refractive power after lenticule extraction treatments. The model provides many input parameters of the patient and the treatment itself, leading to an individual compensation ansatz for different setups. The model is analyzed for a reasonable range of various parameters. A semi-quantitative comparison to real patient data is performed.
{"title":"A simple cornea deformation model","authors":"Tobias Kehrer, Samuel Arba Mosquera","doi":"10.1515/aot-2021-0039","DOIUrl":"https://doi.org/10.1515/aot-2021-0039","url":null,"abstract":"Abstract In this paper, we present a cornea deformation model based on the idea of extending the ‘neutral axis’ model to two-dimensional deformations. Considering this simple model, assuming the corneal tissue to behave like a continuous, isotropic and non-compressible material, we are able to partially describe, e.g., the observed deviation in refractive power after lenticule extraction treatments. The model provides many input parameters of the patient and the treatment itself, leading to an individual compensation ansatz for different setups. The model is analyzed for a reasonable range of various parameters. A semi-quantitative comparison to real patient data is performed.","PeriodicalId":46010,"journal":{"name":"Advanced Optical Technologies","volume":"10 1","pages":"433 - 450"},"PeriodicalIF":1.8,"publicationDate":"2021-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41553242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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