Large aspheric mirrors are ground and polished at the Steward Observatory Mirror Lab (SOML) using stressed-lap polishers under computer control.1,2 Stressed-lap polishing uses large stiff circular polishing tools, which are actively deformed under computer control forcing the lap to continually fit the aspheric mirror surface. The size of the tool is typically one-third to one-sixth the diameter of the minor. As the lap is translated across the rotating minor, the lap's horizontal speed and rotation rate, the total force on the lap, and applied moments to the lap are all dynamically controlled. In order to take full advantage of these many degrees of freedom, computer simulation and optimization software has been developed. The simulation is based on Preston's relation (local removal rate proportional to pressure and relative velocity) but allows the inclusion of non-linear effects based on measured results. The optimization of polishing parameters is accomplished by a damped least squares optimization algorithm which varies the polishing parameters to obtain a desired simulated removal profile. This software has been successfully used at SOML to guide grinding and polishing of numerous large primary and secondary telescope mirrors.3 The software was developed for the stressed lap polishers at the University of Arizona, but it can be used with equal effectiveness for other types of polishers.
{"title":"Simulation and optimization for a computer-controlled large-tool polisher","authors":"J. Burge","doi":"10.1364/oft.1998.omd.2","DOIUrl":"https://doi.org/10.1364/oft.1998.omd.2","url":null,"abstract":"Large aspheric mirrors are ground and polished at the Steward Observatory Mirror Lab (SOML) using stressed-lap polishers under computer control.1,2 Stressed-lap polishing uses large stiff circular polishing tools, which are actively deformed under computer control forcing the lap to continually fit the aspheric mirror surface. The size of the tool is typically one-third to one-sixth the diameter of the minor. As the lap is translated across the rotating minor, the lap's horizontal speed and rotation rate, the total force on the lap, and applied moments to the lap are all dynamically controlled. In order to take full advantage of these many degrees of freedom, computer simulation and optimization software has been developed. The simulation is based on Preston's relation (local removal rate proportional to pressure and relative velocity) but allows the inclusion of non-linear effects based on measured results. The optimization of polishing parameters is accomplished by a damped least squares optimization algorithm which varies the polishing parameters to obtain a desired simulated removal profile. This software has been successfully used at SOML to guide grinding and polishing of numerous large primary and secondary telescope mirrors.3 The software was developed for the stressed lap polishers at the University of Arizona, but it can be used with equal effectiveness for other types of polishers.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"14 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114000775","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}
Recent demands for ultraprecision machining has been for higher precision. The ELID grinding technique is widely known as a method which produces high precision ground surfaces in a short period of time.1) Aspherical optics, one typical example of super precision parts, require not only good mirror surface finish but also high form accuracy.2) But it involves considerable difficulty to achieve both good mirror surface finish and high form accuracy. The authors have proposed a new form control system for achieving high form accuracy regularly and efficiently in aspherical ELID grinding, and successful results could be obtained through some experiments3),4). But there had been some conditions, under which the profile errors could not converge because the radius of the grinding wheel decreased by the wear. This paper proposes a new form compensation method which can be applied to the condition under which the grinding wheel is much worn.
{"title":"New NC Data Generating Method Including Tool Wear Compensation in ELID (Electrolytic In-Process Dressing) Grinding","authors":"S. Moriyasu, Y. Yamagata, H. Ohmori","doi":"10.1364/FTA.1999.GA2","DOIUrl":"https://doi.org/10.1364/FTA.1999.GA2","url":null,"abstract":"Recent demands for ultraprecision machining has been for higher precision. The ELID grinding technique is widely known as a method which produces high precision ground surfaces in a short period of time.1) Aspherical optics, one typical example of super precision parts, require not only good mirror surface finish but also high form accuracy.2) But it involves considerable difficulty to achieve both good mirror surface finish and high form accuracy. The authors have proposed a new form control system for achieving high form accuracy regularly and efficiently in aspherical ELID grinding, and successful results could be obtained through some experiments3),4). But there had been some conditions, under which the profile errors could not converge because the radius of the grinding wheel decreased by the wear. This paper proposes a new form compensation method which can be applied to the condition under which the grinding wheel is much worn.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129310343","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}
In phase shifting interferometry, the image acquisition electronics have largely been ignored, because the overall measurement accuracy has generally been limited by the quality of the reference wave. A recently developed interferometer, the phase shifting diffraction interferometer,[1] provides a high quality reference wave, which has been measured to be better than λ/8000 rms. With such a reference wave, the interferometer accuracy then becomes limited by systematic errors in the image acquisition electronics. This paper presents a variety of issues that arise when using image acquisition electronics of the sort commonly used in commercial interferometers. A basic fiber interferometer that isolates electronics issues is described, as are simple solutions to some of the errors.
{"title":"Image Acquisition for High Accuracy Interferometry","authors":"G. Campbell, G. Sommargren, B. Truax","doi":"10.1364/oft.1998.owc.2","DOIUrl":"https://doi.org/10.1364/oft.1998.owc.2","url":null,"abstract":"In phase shifting interferometry, the image acquisition electronics have largely been ignored, because the overall measurement accuracy has generally been limited by the quality of the reference wave. A recently developed interferometer, the phase shifting diffraction interferometer,[1] provides a high quality reference wave, which has been measured to be better than λ/8000 rms. With such a reference wave, the interferometer accuracy then becomes limited by systematic errors in the image acquisition electronics. This paper presents a variety of issues that arise when using image acquisition electronics of the sort commonly used in commercial interferometers. A basic fiber interferometer that isolates electronics issues is described, as are simple solutions to some of the errors.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"578 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116067176","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}
Yutaka Yamgata, S. Moriyasu, S. Morita, H. Ohmori, T. Higuchi
Due to the progress in fiber optics, optical storage systems and portable information devices, fabrication technologies for micro optical components becomes more and more important. The fabrication process of micro optical componets especially deep concave glass micro lens is facing a number of diffculties: (1)Since the diameter of the micro optical component is very small and the depth of the surface is large, the grinding wheel must have even samller diameter. (2)In order to obtain optimum cicumference speed, the rotation speed of the grinding wheel becomes extremely high. In order to overcome those problems, inclined grinding wheel can be used to cut the deep concave surface. This method solves the first problem but still extremely high rotation speed is necessary. The authors present a new resolution to those problems using ELID (ElectroLytic In-process Drssing) grinding method. Using ELID grinding, the grinding wheel is continuously dressed during the machininig process and always kept sharpened. This results in a very high quality surface finish even under low circumference speed. Fabrication example of glass micro concave lens (radius:4.6mm) is carried out with small grinding wheel (diameter 5mm) at relatively low rotation speed of 20,000 rpm, which is equivalent to 300m/min circumference speed. Surface roughness of 40nmp-ν and profile accuracy of approximately 1μm was obtained.
{"title":"Fabrication of Deep Concave Glass Micro Lens by ELID Grinding","authors":"Yutaka Yamgata, S. Moriyasu, S. Morita, H. Ohmori, T. Higuchi","doi":"10.1364/oft.1998.omc.4","DOIUrl":"https://doi.org/10.1364/oft.1998.omc.4","url":null,"abstract":"Due to the progress in fiber optics, optical storage systems and portable information devices, fabrication technologies for micro optical components becomes more and more important. The fabrication process of micro optical componets especially deep concave glass micro lens is facing a number of diffculties: (1)Since the diameter of the micro optical component is very small and the depth of the surface is large, the grinding wheel must have even samller diameter. (2)In order to obtain optimum cicumference speed, the rotation speed of the grinding wheel becomes extremely high. In order to overcome those problems, inclined grinding wheel can be used to cut the deep concave surface. This method solves the first problem but still extremely high rotation speed is necessary. The authors present a new resolution to those problems using ELID (ElectroLytic In-process Drssing) grinding method. Using ELID grinding, the grinding wheel is continuously dressed during the machininig process and always kept sharpened. This results in a very high quality surface finish even under low circumference speed. Fabrication example of glass micro concave lens (radius:4.6mm) is carried out with small grinding wheel (diameter 5mm) at relatively low rotation speed of 20,000 rpm, which is equivalent to 300m/min circumference speed. Surface roughness of 40nmp-ν and profile accuracy of approximately 1μm was obtained.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122124519","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 ion exchange technique is widely used to produce radial gradient-index lenses, however, has a disadvantage for fabricating much larger ones. It probably takes hundreds days to make the lenses with 20 mm in diameter using this technique. In large scale imaging systems, such large radial gradient-index lenses are required.
{"title":"A New Ion Exchange Technique for Fabricating Radial GI lenses","authors":"Yoshikazu Kaite, M. Toyama, I. Kitano","doi":"10.1364/oft.1988.fb4","DOIUrl":"https://doi.org/10.1364/oft.1988.fb4","url":null,"abstract":"The ion exchange technique is widely used to produce radial gradient-index lenses, however, has a disadvantage for fabricating much larger ones. It probably takes hundreds days to make the lenses with 20 mm in diameter using this technique. In large scale imaging systems, such large radial gradient-index lenses are required.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123840225","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. George, H. Jagannath, B. R. Reddy, G. Perera, P. Venkateswarlu
An optical heterodyne profilometer was fabricated for the measurement of surface roughness. Briefly, when two beams of slightly different frequencies are reflected from two different points on the surface, the phase of the resulting sinusoidal interference signal is related to the height difference between the two points, whose absolute value is estimated by comparing it with the phase of a reference signal, but no reference surface is involved.1
{"title":"Fabrication of an Optical Heterodyne Profilometer","authors":"M. George, H. Jagannath, B. R. Reddy, G. Perera, P. Venkateswarlu","doi":"10.1364/oft.1988.tha5","DOIUrl":"https://doi.org/10.1364/oft.1988.tha5","url":null,"abstract":"An optical heterodyne profilometer was fabricated for the measurement of surface roughness. Briefly, when two beams of slightly different frequencies are reflected from two different points on the surface, the phase of the resulting sinusoidal interference signal is related to the height difference between the two points, whose absolute value is estimated by comparing it with the phase of a reference signal, but no reference surface is involved.1","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127079489","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 measurement of the homogeneity of optical materials is discussed. Methods and equipment for evaluation of both polished and unpolished material samples are described.
讨论了光学材料均匀性的测量方法。描述了评估抛光和未抛光材料样品的方法和设备。
{"title":"Measurement of the homogeneity of optical materials","authors":"G. C. Hunter, L. J. Sutton","doi":"10.1364/oft.1990.othb4","DOIUrl":"https://doi.org/10.1364/oft.1990.othb4","url":null,"abstract":"The measurement of the homogeneity of optical materials is discussed. Methods and equipment for evaluation of both polished and unpolished material samples are described.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126290244","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 Optics and Electro-Optics Standards Council (OEOSC) has been formed to help the U.S. take a more active role in the development, maintenance, and administration of U.S. optics and electro-optics standards, and participate in international standards activities under ISO (International Organization for Standardization). Optics and electro-optics standards activities in the U.S. are in a time of crisis. Without support from U.S. optics and electro-optics companies, these communities will be unable to participate in the world market, and will find it progressively more difficult to engage in domestic production and sales.
{"title":"The Importance of Standards for the U.S. Optics Industry","authors":"Gene Kohlenberg","doi":"10.1364/oft.1996.owb.1","DOIUrl":"https://doi.org/10.1364/oft.1996.owb.1","url":null,"abstract":"The Optics and Electro-Optics Standards Council (OEOSC) has been formed to help the U.S. take a more active role in the development, maintenance, and administration of U.S. optics and electro-optics standards, and participate in international standards activities under ISO (International Organization for Standardization). Optics and electro-optics standards activities in the U.S. are in a time of crisis. Without support from U.S. optics and electro-optics companies, these communities will be unable to participate in the world market, and will find it progressively more difficult to engage in domestic production and sales.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"103 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117291820","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 instruments used to interferometrically measure the optical surfaces of the 6.5-m f/1.25 primary mirrors for the University of Arizona telescope projects must compensate over 800 μm surface departure from the best fitting sphere. The errors in the optical test must not contribute more than 0.04 arc seconds FWHM to the final image and the conic constant must be held to 0.01%. This paper presents an overview of the instruments used to measure these giant mirrors to such high accuracy.
亚利桑那大学望远镜项目中用于干涉测量6.5 m f/1.25主镜光学表面的仪器必须补偿与最佳拟合球的表面偏差超过800 μm。光学测试中的误差对最终图像的贡献不得超过0.04角秒FWHM，并且圆锥常数必须保持在0.01%。本文概述了用于测量这些巨镜的仪器，以达到如此高的精度。
{"title":"Null correctors for 6.5-m f/1.25 paraboloidal mirrors","authors":"J. Burge, L. Dettmann, S. West","doi":"10.1364/FTA.1999.FT5","DOIUrl":"https://doi.org/10.1364/FTA.1999.FT5","url":null,"abstract":"The instruments used to interferometrically measure the optical surfaces of the 6.5-m f/1.25 primary mirrors for the University of Arizona telescope projects must compensate over 800 μm surface departure from the best fitting sphere. The errors in the optical test must not contribute more than 0.04 arc seconds FWHM to the final image and the conic constant must be held to 0.01%. This paper presents an overview of the instruments used to measure these giant mirrors to such high accuracy.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"128 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115830895","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 present decade is an unprecedented period of expansion in the collective power of ground-based optical and infrared telescopes worldwide. No fewer than 13 telescopes between 6.5 m and 10 m in diameter--all larger than the most powerful telescope available before 1990--will be completed by roughly the year 2000. Some of these telescopes are designed with specific scientific goals in mind, such as high-resolution infrared imaging and spectroscopy, while others are multi-purpose instruments designed to serve the needs of an astronomical community whose observations have been limited by collecting area and resolving power for several decades. The projects are listed below.
{"title":"Innovative Optics for Giant Telescopes","authors":"H. Martin","doi":"10.1364/FTA.1999.FT4","DOIUrl":"https://doi.org/10.1364/FTA.1999.FT4","url":null,"abstract":"The present decade is an unprecedented period of expansion in the collective power of ground-based optical and infrared telescopes worldwide. No fewer than 13 telescopes between 6.5 m and 10 m in diameter--all larger than the most powerful telescope available before 1990--will be completed by roughly the year 2000. Some of these telescopes are designed with specific scientific goals in mind, such as high-resolution infrared imaging and spectroscopy, while others are multi-purpose instruments designed to serve the needs of an astronomical community whose observations have been limited by collecting area and resolving power for several decades. The projects are listed below.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115454270","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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