Optical Angular Momentum最新文献

Ultra-precise surface machining of N-BK7 using microwave-driven reactive plasma jet machining 微波驱动反应等离子体射流加工N-BK7超精密表面

Optical Angular Momentum Pub Date : 2019-12-30 DOI: 10.1117/12.2547617

Faezeh Kazemi, G. Boehm, T. Arnold

{"title":"Ultra-precise surface machining of N-BK7 using microwave-driven reactive plasma jet machining","authors":"Faezeh Kazemi, G. Boehm, T. Arnold","doi":"10.1117/12.2547617","DOIUrl":"https://doi.org/10.1117/12.2547617","url":null,"abstract":"Chemically reactive Plasma Jet Machining (PJM) is a contactless and efficient surface machining technique increasingly applied to the surface shape generation and error correction of various optical elements. However, the application of fluorine-based PJM to surface machining of N-BK7® is challenging since the chemical interaction between reactive plasma species and metal components of N-BK7 induces a residual layer in the contact zone and surrounding of the plasma-treated area. It was noticed that a residual layer degrades the ability of obtaining the prerequisite surface profile and causes a nonlinear and hardly predictable removal behavior with respect to the etching time. In this paper, extensive studies are conducted for relaxing constraints in applying the fluorine-based PJM to the surface machining of N-BK7, particularly regarding to the manufacture of freeform optical elements. In this regard, the chemical composition of residual layer is evaluated by using SEM/EDX analysis aiming at clarifying the chemical kinetics between plasma generated active particles and the N-BK7 surface atoms. Furthermore, the etching behavior of N-BK7 is compared with Fused Silica to verify the optimality of obtained results. Finally, the area machining is tested at different plasma dwell times to evaluate the predictability and regularity of results.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123811062","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: 4

Machining vibration and methods of their measurement 加工振动及其测量方法

Optical Angular Momentum Pub Date : 2019-12-30 DOI: 10.1117/12.2542816

M. Špína, J. Benes, F. Procháska, O. Matousek

{"title":"Machining vibration and methods of their measurement","authors":"M. Špína, J. Benes, F. Procháska, O. Matousek","doi":"10.1117/12.2542816","DOIUrl":"https://doi.org/10.1117/12.2542816","url":null,"abstract":"Today, aspherical elements have become an indispensable part of modern high-precision optical assemblies. Several kinds of defects arise during their manufacture. As far as very precise aspherical surfaces are concerned, mid-spatial frequencies are probably the most important issue. This type of imperfection fills the gap between shape (low-spatial frequencies) and microroughness (high-spatial frequencies). A smaller part of these defects arise during polishing; however, more of them are generated during the grinding process. Due to the interference of different controlling frequencies in the machine and imperfections in the constructional solution of the grinding machine, defects occur on the optical surface, which deform it. The periods of these defects usually lie in an interval of 0.5 to 10 mm, depending on the parameters of the machining process. To prevent the generation of these structures, a comprehensive measurement of the sources and transmission of vibrations was realised using the measuring device VibXpert II. The measurement was made on the grinding machine Optotech MCG 100 CNC. Several simulations of different types of processes were realised and the measurement was also subsequently performed during a real grinding process of aspherical optical surfaces. The data acquired from the measurement of vibrations were mathematically processed in frequency space. The experiment revealed several reasons for these defects.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"211 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123234919","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

Study of the influence of focal position on back-reflected radiation during deep penetration laser welding and its simulation 深熔激光焊接中焦点位置对反向反射辐射的影响及其仿真研究

Optical Angular Momentum Pub Date : 2019-12-30 DOI: 10.1117/12.2542806

P. Horník, M. Šarbort, Hana Šebestová, L. Mrňa

引用次数: 1

Mobile LIDT

Optical Angular Momentum Pub Date : 2019-12-30 DOI: 10.1117/12.2542776

Martin Mydlář, J. Vanda, M. Mureșan, P. Čech, J. Brajer, T. Mocek

引用次数: 0

Investigations of dental cavities: between x-ray radiography and OCT 龋齿的调查:x线摄影与OCT的比较

Optical Angular Momentum Pub Date : 2019-12-30 DOI: 10.1117/12.2542904

Ralph-Alexandru Erdelyi, Virgil-Florin Duma, G. Dobre, A. Bradu, A. Podoleanu

{"title":"Investigations of dental cavities: between x-ray radiography and OCT","authors":"Ralph-Alexandru Erdelyi, Virgil-Florin Duma, G. Dobre, A. Bradu, A. Podoleanu","doi":"10.1117/12.2542904","DOIUrl":"https://doi.org/10.1117/12.2542904","url":null,"abstract":"Nowadays in dentistry a correct diagnosis is given only after a clinical and radiological evaluation. Radiographs are also required for treatment assessments. The aim of this study is to present results obtained on evaluating dental cavities in a dental clinic in Western Romania, using both X-ray radiography and Optical Coherence Tomography (OCT). The most common methods for daily-basis clinical imaging are utilized, i.e. panoramic radiography and three-dimensional (3D) cone beam computed tomography (CBCT). Advantages of OCT as an imaging method in dentistry are discussed: it avoids exposing the patient to X-ray radiation, and image resolution of OCT is superior. This led us to test this technique for dental assessments and see how it can work in conjunction with radiography. The study also provides upsides and downsides of both medical imaging techniques. Panoramic radiographs and 3D CBCT to several extracted teeth are performed. Dedicated toolbars from Romexis software (Planmeca, Helsinki, Finland) are analyzed with regard to their capability to make precise measurements. Processing of images are made to obtain a high-quality; measurements are done and data are collected. The same teeth are scanned with an in-house developed SS-OCT system. Images from both investigations are presented, and clinical conclusions are drawn. For dental issues (i.e., cavities) that appear on the surface of the teeth, OCT proves to be more suitable than radiographs; it is also more accurate and radiation-free.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"159 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121321009","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: 4

Measurement of small optics by use of a multi-wavelength interferometrical approach 用多波长干涉法测量小型光学器件

Optical Angular Momentum Pub Date : 2019-12-30 DOI: 10.1117/12.2542914

M. Wendel

引用次数: 1

Preliminary design of longitudinal chromatic aberration sensor implemented to laser processing head 应用于激光加工头的纵向色差传感器初步设计

Optical Angular Momentum Pub Date : 2019-12-30 DOI: 10.1117/12.2542409

M. Ćwikła, A. Zakrzewski, P. Koruba, P. Jurewicz, J. Reiner

{"title":"Preliminary design of longitudinal chromatic aberration sensor implemented to laser processing head","authors":"M. Ćwikła, A. Zakrzewski, P. Koruba, P. Jurewicz, J. Reiner","doi":"10.1117/12.2542409","DOIUrl":"https://doi.org/10.1117/12.2542409","url":null,"abstract":"The problem of process monitoring is one of the most critical aspects of control in laser material processing. Chromatic sensors, which are characterized by high resolution, relatively large measurement range and good repeatability, may be used for measuring and adjusting the distance between laser head and the substrate. In this paper we propose a new solution of chromatic sensor integrated with optical laser head via an available standard monitoring port. Optical components of laser heads are fabricated from materials characterized by high Abbe number (low range of longitudinal chromatic aberration). Therefore, for sensors application, the resulting chromatic aberration of the overall optical system should be enhanced by implementation the sets of lens described by a low value of Abbe. The numerical analysis were carried out in order to design an optical system of proposed solution, which will be described by wide measurement range, low attenuation and narrow characteristic spectral peak. The results obtained by WinLens software solutions were presented. The numerical tool whose principle of operation is based on geometric optics equations, was chosen for rapid prototyping because of its simplicity in implementation of optical components. The results from the numerical analysis were afterwards confirmed by the experiment on real optical system.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130270157","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

Photometry of exoplanet transits and their regular monitoring 系外行星凌日的光度测定及其定期监测

Optical Angular Momentum Pub Date : 2019-12-30 DOI: 10.1117/12.2543153

P. Pintr, David Vápenka, Z. Rail

引用次数: 0

Ion beam figuring with using Einzel lens 用艾因泽尔透镜计算离子束

Optical Angular Momentum Pub Date : 2019-12-30 DOI: 10.1117/12.2542822

V. Karabyn, J. Polák, F. Procháska, R. Melich

引用次数: 0

Measurement of mechanical properties of GRIN rod lens GRIN杆透镜力学性能的测量

Optical Angular Momentum Pub Date : 2019-12-30 DOI: 10.1117/12.2542913

J. Hošek, S. Nemcová

{"title":"Measurement of mechanical properties of GRIN rod lens","authors":"J. Hošek, S. Nemcová","doi":"10.1117/12.2542913","DOIUrl":"https://doi.org/10.1117/12.2542913","url":null,"abstract":"The GRIN rod lenses are favorable optical elements for the image transmission in applications where transverse dimensions of the optical system are limited such as rigid borescopes or endoscopes. Flexible versions of these instruments usually use imaging bundles of optical fibers to assure both the mechanical elasticity and the optical transmission. The image resolution of this solution suffers from being limited by minimum fiber core diameter allowable for imaging and total number of fibers in a given cross-section area. GRIN rod lens allows for a higher image resolution for small diameters. While the optical properties of the GRIN rod lens are well known, there is no information about its allowed mechanical stress. In this paper we present a simple system for load and deformation measurement of a GRIN rod lens aimed to be used for a miniature endoscope for eye surgery operation. The system allows for loading force measurement with a deformation strain gauge cell and deformation measurement with an optical triangulation sensor. The paper presents deformation limits of the tested GRIN rod lens loaded by a three-point bending test. We also evaluated the Young modulus of the GRIN rod lens material from the measured data. Our data shows that tested GRIN lenses can be statically deformed by bending down to minimum radius 105 mm without braking.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128434237","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