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.
{"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}
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.
如今，非球面元件已成为现代高精度光学组件中不可缺少的一部分。在制造过程中会出现几种缺陷。就非常精确的非球面而言，中空间频率可能是最重要的问题。这种类型的缺陷填补了形状(低空间频率)和微粗糙度(高空间频率)之间的差距。这些缺陷的一小部分是在抛光过程中产生的;然而，更多的是在磨削过程中产生的。由于机床内不同控制频率的干扰和磨床结构方案的不完善，导致光学表面产生缺陷，使其变形。这些缺陷的周期通常在0.5到10mm之间，这取决于加工过程的参数。为了防止这些结构的产生，使用测量设备VibXpert II实现了对振动源和传播的全面测量。测量在Optotech MCG 100 CNC磨床上进行。实现了几种不同类型加工过程的模拟，并随后在非球面光学表面的实际磨削过程中进行了测量。从振动测量中获得的数据在频率空间中进行数学处理。实验揭示了造成这些缺陷的几个原因。
{"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}
A penetration laser welding mode characterized by formation of keyhole is often used. A small portion of the laser beam is reflected back from the keyhole and returned to the laser through the optical system of the welding head and optical fiber. The reflected radiation is monitored in the laser for the safety of the optical resonator and its signal can be read and used for process monitoring. The experiment was conducted to relate the intensity of the back-reflected radiation with depth and width of the weld for the variable focal position. The experiments were performed for two variants of the optical focusing system and materials with different thermo-physical properties - carbon steel and stainless steel. Furthermore, a mathematical model for back-reflected radiation was created using ray tracing. The shape of the keyhole was approximated as an inclined conical cavity. The results of the simulation were compared with experimentally measured data and it was found that the proposed model is most suitable for the description of stainless steel.
{"title":"Study of the influence of focal position on back-reflected radiation during deep penetration laser welding and its simulation","authors":"P. Horník, M. Šarbort, Hana Šebestová, L. Mrňa","doi":"10.1117/12.2542806","DOIUrl":"https://doi.org/10.1117/12.2542806","url":null,"abstract":"A penetration laser welding mode characterized by formation of keyhole is often used. A small portion of the laser beam is reflected back from the keyhole and returned to the laser through the optical system of the welding head and optical fiber. The reflected radiation is monitored in the laser for the safety of the optical resonator and its signal can be read and used for process monitoring. The experiment was conducted to relate the intensity of the back-reflected radiation with depth and width of the weld for the variable focal position. The experiments were performed for two variants of the optical focusing system and materials with different thermo-physical properties - carbon steel and stainless steel. Furthermore, a mathematical model for back-reflected radiation was created using ray tracing. The shape of the keyhole was approximated as an inclined conical cavity. The results of the simulation were compared with experimentally measured data and it was found that the proposed model is most suitable for the description of stainless steel.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"92 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":"126199809","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}
Martin Mydlář, J. Vanda, M. Mureșan, P. Čech, J. Brajer, T. Mocek
Laser Induced Damage Threshold (LIDT) is an important property of laser system components. It is obtained as a statistical value from controlled experiments and defines the maximum optical intensity, which does not cause damage to certain components. Correlation between maximum optical intensity, beam pulse length and focal spot size provides a unique characterization of a specimen. Some specimen requires conditions or environment unreachable in stationary setup, therefore a lighten, portable, version of testing setup may be used with proper source and surroundings. The advantage of the mobile LIDT station is access to different laser systems with variety of beam properties (repetition rate, pulse length, etc). In following paper were investigated accuracy of measurements done by the mobile LIDT station and copared to stationary, ISO compliant LIDT station measurements as reference.
{"title":"Mobile LIDT","authors":"Martin Mydlář, J. Vanda, M. Mureșan, P. Čech, J. Brajer, T. Mocek","doi":"10.1117/12.2542776","DOIUrl":"https://doi.org/10.1117/12.2542776","url":null,"abstract":"Laser Induced Damage Threshold (LIDT) is an important property of laser system components. It is obtained as a statistical value from controlled experiments and defines the maximum optical intensity, which does not cause damage to certain components. Correlation between maximum optical intensity, beam pulse length and focal spot size provides a unique characterization of a specimen. Some specimen requires conditions or environment unreachable in stationary setup, therefore a lighten, portable, version of testing setup may be used with proper source and surroundings. The advantage of the mobile LIDT station is access to different laser systems with variety of beam properties (repetition rate, pulse length, etc). In following paper were investigated accuracy of measurements done by the mobile LIDT station and copared to stationary, ISO compliant LIDT station measurements as reference.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"50 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":"114466100","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}
Ralph-Alexandru Erdelyi, Virgil-Florin Duma, G. Dobre, A. Bradu, A. Podoleanu
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.
{"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}
A new approach for measurement of small and thin lenses is introduced, based on the combination of long and short coherence interferometrical point probe systems in one measurement device. The basic working principle, as well as first results, are presented, and the benefits of this approach are highlighted.
{"title":"Measurement of small optics by use of a multi-wavelength interferometrical approach","authors":"M. Wendel","doi":"10.1117/12.2542914","DOIUrl":"https://doi.org/10.1117/12.2542914","url":null,"abstract":"A new approach for measurement of small and thin lenses is introduced, based on the combination of long and short coherence interferometrical point probe systems in one measurement device. The basic working principle, as well as first results, are presented, and the benefits of this approach are highlighted.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"114 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":"131920912","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}
M. Ćwikła, A. Zakrzewski, P. Koruba, P. Jurewicz, J. Reiner
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.
{"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}
We report photometric measurements of selected exoplanet transits from the archive of the TOPTEC telescope, operated by our team at an observatory Horní Halže, near Klášterec nad Ohří, Czech Republic. We have compared measured geometry with catalogue geometry of selected exoplanetary systems. We have found a candidate for potential system with new non-transiting planet with the help of an archive TRESCA.
我们报告了在捷克共和国Klášterec nad Ohří附近的天文台Horní Halže，由我们的团队操作的TOPTEC望远镜档案中选定的系外行星凌日的光度测量结果。我们将测量的几何形状与选定的系外行星系统的目录几何形状进行了比较。在TRESCA档案的帮助下，我们发现了一个具有新的非凌日行星的潜在系统候选者。
{"title":"Photometry of exoplanet transits and their regular monitoring","authors":"P. Pintr, David Vápenka, Z. Rail","doi":"10.1117/12.2543153","DOIUrl":"https://doi.org/10.1117/12.2543153","url":null,"abstract":"We report photometric measurements of selected exoplanet transits from the archive of the TOPTEC telescope, operated by our team at an observatory Horní Halže, near Klášterec nad Ohří, Czech Republic. We have compared measured geometry with catalogue geometry of selected exoplanetary systems. We have found a candidate for potential system with new non-transiting planet with the help of an archive TRESCA.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"29 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":"127877886","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}
Ion Beam Figuring (IBF) has been used for nearly 20 years by several laboratories and companies as a highly deterministic method of final processing of ultra-precision optical elements. Nowadays, requirements for high precision optics demand to have full control over the ion beam, which includes both the ion beam profile and intensity. Electrostatic focusing using an Einzel lens setup provides a simple option to control the ion beam shape by changing voltage. This experimental study investigates the early stage development of an Einzel lens used to control an RF40 ion source. First results demonstrate the possibility to use an Einzel lens to control the ion beam profile and indicate possible future challenges this technology has to overcome when used in IBF machines.
{"title":"Ion beam figuring with using Einzel lens","authors":"V. Karabyn, J. Polák, F. Procháska, R. Melich","doi":"10.1117/12.2542822","DOIUrl":"https://doi.org/10.1117/12.2542822","url":null,"abstract":"Ion Beam Figuring (IBF) has been used for nearly 20 years by several laboratories and companies as a highly deterministic method of final processing of ultra-precision optical elements. Nowadays, requirements for high precision optics demand to have full control over the ion beam, which includes both the ion beam profile and intensity. Electrostatic focusing using an Einzel lens setup provides a simple option to control the ion beam shape by changing voltage. This experimental study investigates the early stage development of an Einzel lens used to control an RF40 ion source. First results demonstrate the possibility to use an Einzel lens to control the ion beam profile and indicate possible future challenges this technology has to overcome when used in IBF machines.","PeriodicalId":112965,"journal":{"name":"Optical Angular Momentum","volume":"11 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":"131091059","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}
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.
{"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}
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