Optical Angular Momentum最新文献_第4页

Four new variable stars in Cassiopea discovered with DSLR camera 用数码单反相机发现仙后座上的四颗新变星

Optical Angular Momentum Pub Date : 2016-11-11 DOI: 10.1117/12.2256658

P. Pintr, David Vápenka, M. Mašek

引用次数: 0

Compact and robust hyperspectral camera based on compressed sensing 基于压缩感知的紧凑鲁棒高光谱相机

Optical Angular Momentum Pub Date : 2016-11-11 DOI: 10.1117/12.2250268

K. Žídek, Ondřej Denk, J. Hlubuček, J. Václavík

{"title":"Compact and robust hyperspectral camera based on compressed sensing","authors":"K. Žídek, Ondřej Denk, J. Hlubuček, J. Václavík","doi":"10.1117/12.2250268","DOIUrl":"https://doi.org/10.1117/12.2250268","url":null,"abstract":"Spectrum of light which is emitted or reflected by an object carries immense amount of information about the object. A simple piece of evidence is the importance of color sensing for human vision. Combining an image acquisition with efficient measurement of light spectra for each detected pixel is therefore one of the important issues in imaging, referred as hyperspectral imaging. We demonstrate a construction of a compact and robust hyperspectral camera for the visible and near-IR spectral region. The camera was designed vastly based on off-shelf optics, yet an extensive optimization and addition of three customized parts enabled construction of the camera featuring a low f-number (F/3.9) and fully concentric optics. We employ a novel approach of compressed sensing (namely coded aperture snapshot spectral imaging, abbrev. CASSI). The compressed sensing enables to computationally extract an encoded hyperspectral information from a single camera exposition. Owing to the technique the camera lacks any moving or scanning part, while it can record the full image and spectral information in a single snapshot. Moreover, unlike the commonly used compressed sensing table-top apparatuses, the camera represents a portable device able to work outside a lab. We demonstrate the spectro-temporal reconstruction of recorded scenes based on 90×90 random matrix encoding. Finally, we discuss potential of the compressed sensing in hyperspectral camera.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127479935","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}

引用次数: 2

FEM analysis of bonding process used for minimization of deformation of optical surface under Metis coronagraph mirrors manufacturing Metis日冕反射镜制造中光学表面最小变形粘接工艺的有限元分析

Optical Angular Momentum Pub Date : 2016-11-11 DOI: 10.1117/12.2256705

F. Procháska, T. Vít, O. Matousek, R. Melich

引用次数: 1

Robust retrieval of optical surfaces phase maps in sub-Nyquist multi-wavelength interferometry 亚奈奎斯特多波长干涉测量中光学表面相位图的鲁棒检索

Optical Angular Momentum Pub Date : 2016-11-11 DOI: 10.1117/12.2256837

P. Psota, V. Ledl, P. Vojtíšek, O. Matousek

引用次数: 0

Losses in TiO2/SiO2 multilayer coatings TiO2/SiO2多层涂层中的损耗

Optical Angular Momentum Pub Date : 2016-11-11 DOI: 10.1117/12.2257232

Jiří Budasz, J. Hutka, J. Václavík

{"title":"Losses in TiO2/SiO2 multilayer coatings","authors":"Jiří Budasz, J. Hutka, J. Václavík","doi":"10.1117/12.2257232","DOIUrl":"https://doi.org/10.1117/12.2257232","url":null,"abstract":"This paper deals with optical losses in the coatings consisting of a combination of titanium dioxide (TiO2) and silicon dioxide (SiO2) layers evaporated by the ion beam assisted deposition (IBAD). This combination is commonly used for optical coatings as a standard choice for antireflective or any other optical filter in the visible and near IR range. Although the technology has been known for decades, we point out that some undescribed parasite losses can still appear and we show how to deal with them. In fact, in some cases, the losses made the target coating even inapplicable. In this paper we try to investigate the origin of the losses and we describe the deposition parameters which allow us to reduce or completely remove them. We determined whether the losses are proportional to the total thickness of the coating or to the number of layers. The influence of scattering was measured as well. Deposition parameters which were studied are the substrate temperature, discharge voltage of the assisting ion gun, oxygen flow of the assisting ion gun and the deposition rate, especially its starting curve. Influence of the post process annealing was studied as well. Starting curve of the deposition rate of SiO2 layer and the amount of oxygen flowing through the assisting ion gun were found as a crucial parameters.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122938797","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}

引用次数: 0

Minimising back reflections from the common path objective in a fundus camera 眼底相机中共同路径物镜的反射最小化

Optical Angular Momentum Pub Date : 2016-11-11 DOI: 10.1117/12.2256633

A. Swat

{"title":"Minimising back reflections from the common path objective in a fundus camera","authors":"A. Swat","doi":"10.1117/12.2256633","DOIUrl":"https://doi.org/10.1117/12.2256633","url":null,"abstract":"Eliminating back reflections is critical in the design of a fundus camera with internal illuminating system. As there is very little light reflected from the retina, even excellent antireflective coatings are not sufficient suppression of ghost reflections, therefore the number of surfaces in the common optics in illuminating and imaging paths shall be minimised. Typically a single aspheric objective is used. In the paper an alternative approach, an objective with all spherical surfaces, is presented. As more surfaces are required, more sophisticated method is needed to get rid of back reflections. Typically back reflections analysis, comprise treating subsequent objective surfaces as mirrors, and reflections from the objective surfaces are traced back through the imaging path. This approach can be applied in both sequential and nonsequential ray tracing. It is good enough for system check but not very suitable for early optimisation process in the optical system design phase. There are also available standard ghost control merit function operands in the sequential ray-trace, for example in Zemax system, but these don’t allow back ray-trace in an alternative optical path, illumination vs. imaging. What is proposed in the paper, is a complete method to incorporate ghost reflected energy into the raytracing system merit function for sequential mode which is more efficient in optimisation process. Although developed for the purpose of specific case of fundus camera, the method might be utilised in a wider range of applications where ghost control is critical.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130160209","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}

引用次数: 0

Digital holographic tomography method for 3D observation of domain patterns in ferroelectric single crystals 铁电单晶畴图三维观测的数字全息层析成像方法

Optical Angular Momentum Pub Date : 2016-11-11 DOI: 10.1117/12.2257327

P. Mokry, P. Psota, K. Steiger, J. Václavík, David Vápenka, R. Dolecek, P. Vojtíšek, J. Sládek, V. Ledl

{"title":"Digital holographic tomography method for 3D observation of domain patterns in ferroelectric single crystals","authors":"P. Mokry, P. Psota, K. Steiger, J. Václavík, David Vápenka, R. Dolecek, P. Vojtíšek, J. Sládek, V. Ledl","doi":"10.1117/12.2257327","DOIUrl":"https://doi.org/10.1117/12.2257327","url":null,"abstract":"We report on the development and implementation of the digital holographic tomography for the three-dimensio- nal (3D) observations of the domain patterns in the ferroelectric single crystals. Ferroelectric materials represent a group of materials, whose macroscopic dielectric, electromechanical, and elastic properties are greatly in uenced by the presence of domain patterns. Understanding the role of domain patterns on the aforementioned properties require the experimental techniques, which allow the precise 3D measurements of the spatial distribution of ferroelectric domains in the single crystal. Unfortunately, such techniques are rather limited at this time. The most frequently used piezoelectric atomic force microscopy allows 2D observations on the ferroelectric sample surface. Optical methods based on the birefringence measurements provide parameters of the domain patterns averaged over the sample volume. In this paper, we analyze the possibility that the spatial distribution of the ferroelectric domains can be obtained by means of the measurement of the wavefront deformation of the transmitted optical wave. We demonstrate that the spatial distribution of the ferroelectric domains can be determined by means of the measurement of the spatial distribution of the refractive index. Finally, it is demonstrated that the measurements of wavefront deformations generated in ferroelectric polydomain systems with small variations of the refractive index provide data, which can be further processed by means of the conventional tomographic methods.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"283 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131228072","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}

引用次数: 0

Development of swinging part profilometer for optics 光学摆动部件轮廓仪的研制

Optical Angular Momentum Pub Date : 2016-11-11 DOI: 10.1117/12.2256295

Peng Zhang, Jie-ping Li, Guoyu Yu, D. Walker

引用次数: 6

The mounting system of lenses in ASPIICS coronagraph ASPIICS日冕仪中透镜的安装系统

Optical Angular Momentum Pub Date : 2016-11-11 DOI: 10.1117/12.2257230

M. Veselý, T. Vít, J. Plestil

{"title":"The mounting system of lenses in ASPIICS coronagraph","authors":"M. Veselý, T. Vít, J. Plestil","doi":"10.1117/12.2257230","DOIUrl":"https://doi.org/10.1117/12.2257230","url":null,"abstract":"This article describes the mounting system of lenses in a coronagraph ASPIICS (Association of Spacecraft for Polarimetric Imaging Investigation of the Corona of the Sun). ASPIICS is developed and produced in cooperation of twenty partners from seven countries. It is a part of the ESA's PROBA-3 mission, which includes a formation flight of a pair of satellites at orbit. Coronagraph itself consists of three objectives, where the last one is composed by one objective tube for each lens plus holder and Lyot stop. To achieve high accuracy of mounting of the individual lenses, it was necessary to achieve tight geometric and dimensional tolerances for manufacturing of the objectives barrels. In order to minimize the stress and to prevent the displacement of the lens from ideal position during a temperature change on orbit, an athermal solution was proposed. This is achieved by inserting a Teflon ring of a suitable thickness between the lens surface, objective barrel and the spring washer with a precisely defined contact force. It was necessary to find a suitable technological process of manufacturing, because of the specific behavior of PTFE during turning and complex design of other parts. All parameters of mounting system were repeatedly verified by a thermomechanical analysis in FEM software, based on tests of real parts.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115323377","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}

引用次数: 0

Broadband antireflective coating for NEOSTED NEOSTED宽频带减反射涂层

Optical Angular Momentum Pub Date : 2016-11-11 DOI: 10.1117/12.2257233

Jiří Budasz, J. Junek, J. Václavík

{"title":"Broadband antireflective coating for NEOSTED","authors":"Jiří Budasz, J. Junek, J. Václavík","doi":"10.1117/12.2257233","DOIUrl":"https://doi.org/10.1117/12.2257233","url":null,"abstract":"This paper deals with the development of a broadband antireflective coating for a special optical components for the NEOSTED project by European Space Agency (ESA). The aim of this work was to find a suitable design of the optical coating and to develop its production process so it meets the main requirement in which the average reflectance of the coating must be under 0.5 % for wavelengths in the range of 470 - 770 nm. The combination of titanium dioxide (TiO2) and silicon dioxide (SiO2) prepared by the ion beam assisted deposition (IBAD) was chosen for practical experiments and finally for the production as well. The final decision among the proposed designs and materials involved especially the number of layers used in the design in combination with the thickness control technology. From preproduction tests it turned out that the quartz monitor with the thickness set point correction based on a post process measurement is suitable for controlling deposited thickness in the application. This paper presents data from the preproduction tests and data from the first part of the production. A homogeneity of the deposited layer thickness was evaluated based on the measurement of the thickness across the sample.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131718308","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}

引用次数: 1