While phase shifting interferometry (PSI) techniques are not new, they date back at least to the 1950's1 and 1960's2, there is currently much interest in the use of PSI techniques for interferometric optical testing. This interest is at least partly due to the availability of both one-dimensional and two-dimensional solid state detector arrays and microprocessors.
{"title":"Review of Phase Shifting Interferometry","authors":"J. Wyant","doi":"10.1364/oft.1984.wda3","DOIUrl":"https://doi.org/10.1364/oft.1984.wda3","url":null,"abstract":"While phase shifting interferometry (PSI) techniques are not new, they date back at least to the 1950's1 and 1960's2, there is currently much interest in the use of PSI techniques for interferometric optical testing. This interest is at least partly due to the availability of both one-dimensional and two-dimensional solid state detector arrays and microprocessors.","PeriodicalId":170034,"journal":{"name":"Workshop on Optical Fabrication and Testing","volume":"242 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":"124666571","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 discuss the experimental verification of relations derived earlier (1) between observable plasma etch rate, selectivity and anisotropy and reactor parameters for a variety of etch gases. Since the hetergeneous etch reaction is a superposition of neutral and ionic components, it can be shown that such etch chemistry exhibits enhancement and is made anisotropic by the energy transport of ions to the etch surface only when the process is ion dominated. The ion energy transport is controlled by the plasma sheath electric field-electrode area/gas pressure-collision cross section ratio, E.A./pQ, similarly controlling chemical anisotropy for ion dominated etch reactions. Under such circumstances, we show that many etch gases can yield identical ion transport, etch rate and anisotropy for a given rf current, gas pressure, ion-neutral collision cross section & electrode area, Irf/pQA.
{"title":"Control of Plasma Etch Rates, Selectivity and Anisotropy with Plasma Parameters","authors":"L. D. Bollinger, C. Zarowin","doi":"10.1364/oft.1987.pdp1","DOIUrl":"https://doi.org/10.1364/oft.1987.pdp1","url":null,"abstract":"We discuss the experimental verification of relations derived earlier\u0000 (1) between observable plasma etch rate, selectivity and anisotropy\u0000 and reactor parameters for a variety of etch gases. Since the\u0000 hetergeneous etch reaction is a superposition of neutral and ionic\u0000 components, it can be shown that such etch chemistry exhibits\u0000 enhancement and is made anisotropic by the energy transport of ions to\u0000 the etch surface only when the process is ion dominated. The ion\u0000 energy transport is controlled by the plasma sheath electric\u0000 field-electrode area/gas pressure-collision cross section ratio,\u0000 E.A./pQ, similarly controlling chemical anisotropy for ion dominated\u0000 etch reactions. Under such circumstances, we show that many etch gases\u0000 can yield identical ion transport, etch rate and anisotropy for a\u0000 given rf current, gas pressure, ion-neutral collision cross section\u0000 & electrode area, Irf/pQA.","PeriodicalId":170034,"journal":{"name":"Workshop on Optical Fabrication and Testing","volume":"21 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":"128394329","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}
Optical fibers and ball bearings can be used as test tools. An optical fiber may be easily fashioned into a bright source that causes a minimum of obscuration. Ball bearings may be repolished to nearly perfect spheres and used as autoreflecting optics at nearly suitability sible foci in certain tests. Finally we look at the Ronchi test and discuss its suitability as a test device in many differing situations.
{"title":"Optical Tests Using Fibers, Balls, and Ronchi Gratings","authors":"Robert E. Parks","doi":"10.1364/oft.1980.ffa7","DOIUrl":"https://doi.org/10.1364/oft.1980.ffa7","url":null,"abstract":"Optical fibers and ball bearings can be used as test tools. An optical fiber may be easily fashioned into a bright source that causes a minimum of obscuration. Ball bearings may be repolished to nearly perfect spheres and used as autoreflecting optics at nearly suitability sible foci in certain tests. Finally we look at the Ronchi test and discuss its suitability as a test device in many differing situations.","PeriodicalId":170034,"journal":{"name":"Workshop on Optical Fabrication and Testing","volume":"38 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":"130007931","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 Polaroid Spectra Camera contains an unusual telescopic viewfinder comprised of injection molded components and glass mirrors. The reverse telephoto design includes seven lenses, five aspheric surfaces, and two prisms. Figure 1 depicts the Spectra Camera and the location of the viewfinder 24 and the orientation of the optical axis OAv of the viewfinder. Figure 2 depicts the folded optical path. Note that the image is erected using a 4 mirror system. Figure 3 is a layout of the unfolded optical path. The surfaces marked by asterisks are aspheric. All of the lenses are fabricated by injection molding acrylic plastic. Camera geometry dictated a folded optical path and imposed severe packaging requirements. Figure 4 is an exploded view of the entire viewfinder assembly. All of these components (with the exception of parts 184 and 198) are machine assembled, aligned and tested using an automated assembly machine. Parts are placed into the viewfinder housing using pick-and-place units or robots and are retained by snaps, clips, or retainer housings. Cycle time for each assembly step is less than 5 seconds. The viewfinder is bore sighted by adjusting the vertical tilt of 40 (mirror 1) and the lateral position of the field mask 48. The system focus is verified using a modulation measurement technique which images a rotating radial grating through the viewfinder and onto a slit. There is no adjustment for focus. Poorly focused assemblies are discarded; hence, it is imperative that high piece part quality be maintained and that the design allow for reasonable tolerance stack up. Figures 5 and 6 depict details of a snap mount and the one mirror alignment screw.
{"title":"Fabrication and Assembly of a High Production Injection Molded Optical System","authors":"S. D. Fantone","doi":"10.1364/oft.1987.faa1","DOIUrl":"https://doi.org/10.1364/oft.1987.faa1","url":null,"abstract":"The Polaroid Spectra Camera contains an unusual telescopic viewfinder comprised of injection molded components and glass mirrors. The reverse telephoto design includes seven lenses, five aspheric surfaces, and two prisms. Figure 1 depicts the Spectra Camera and the location of the viewfinder 24 and the orientation of the optical axis OAv of the viewfinder. Figure 2 depicts the folded optical path. Note that the image is erected using a 4 mirror system. Figure 3 is a layout of the unfolded optical path. The surfaces marked by asterisks are aspheric. All of the lenses are fabricated by injection molding acrylic plastic. Camera geometry dictated a folded optical path and imposed severe packaging requirements. Figure 4 is an exploded view of the entire viewfinder assembly. All of these components (with the exception of parts 184 and 198) are machine assembled, aligned and tested using an automated assembly machine. Parts are placed into the viewfinder housing using pick-and-place units or robots and are retained by snaps, clips, or retainer housings. Cycle time for each assembly step is less than 5 seconds. The viewfinder is bore sighted by adjusting the vertical tilt of 40 (mirror 1) and the lateral position of the field mask 48. The system focus is verified using a modulation measurement technique which images a rotating radial grating through the viewfinder and onto a slit. There is no adjustment for focus. Poorly focused assemblies are discarded; hence, it is imperative that high piece part quality be maintained and that the design allow for reasonable tolerance stack up. Figures 5 and 6 depict details of a snap mount and the one mirror alignment screw.","PeriodicalId":170034,"journal":{"name":"Workshop on Optical Fabrication and Testing","volume":"104 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":"127863289","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}
This presentation is concerned with the general process of optical fabrication and serves as an introduction to the talks which follow. The intent is to provide a basic understanding of the approaches which are used to fabricate the wide variety of optical materials available today.
{"title":"An Overview of the Fabrication Process","authors":"S. D. Fantone","doi":"10.1364/oft.1986.tua1","DOIUrl":"https://doi.org/10.1364/oft.1986.tua1","url":null,"abstract":"This presentation is concerned with the general process of optical fabrication and serves as an introduction to the talks which follow. The intent is to provide a basic understanding of the approaches which are used to fabricate the wide variety of optical materials available today.","PeriodicalId":170034,"journal":{"name":"Workshop on Optical Fabrication and Testing","volume":"14 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":"131683541","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}
Two sets of identical Cassegrainian telescope pairs have been manufactured for a space navigation device. A simplified wear program was utilized to grind and polish the primary mirrors which proved to be beneficial. For final aspherizing, however, the calculation process for residual errors proved to be too time consuming and could not handle asymmetric errors. New tooling techniques were tried and found to be advantageous. The master opticians and engineers gained new insight into the computer directed polishing process. The optical system configuration and design requirements are described.
{"title":"On Making Dual-Function Telescope Pairs: An Application of Computer-Directed Polishing (Without the Computer)","authors":"H. Vandermeer, P. Valleli","doi":"10.1364/oft.1980.tua3","DOIUrl":"https://doi.org/10.1364/oft.1980.tua3","url":null,"abstract":"Two sets of identical Cassegrainian telescope pairs have been manufactured for a space navigation device. A simplified wear program was utilized to grind and polish the primary mirrors which proved to be beneficial. For final aspherizing, however, the calculation process for residual errors proved to be too time consuming and could not handle asymmetric errors. New tooling techniques were tried and found to be advantageous. The master opticians and engineers gained new insight into the computer directed polishing process. The optical system configuration and design requirements are described.","PeriodicalId":170034,"journal":{"name":"Workshop on Optical Fabrication and Testing","volume":"27 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":"126764148","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}
Optical contacting is usually used in the traditional machine polishing method for manufacturing precise angle prism. The defects of this method are well known; Strict technical specification and complex equipments are required. So it is hard to get high level accuracy. In general speaking, the angle accuracy is not easy with a tolerance of less than 2".
{"title":"Manufacturing Techniques for Large-Side Ultraprecision Prism","authors":"M. Yin","doi":"10.1364/oft.1984.fda2","DOIUrl":"https://doi.org/10.1364/oft.1984.fda2","url":null,"abstract":"Optical contacting is usually used in the traditional machine polishing method for manufacturing precise angle prism. The defects of this method are well known; Strict technical specification and complex equipments are required. So it is hard to get high level accuracy. In general speaking, the angle accuracy is not easy with a tolerance of less than 2\".","PeriodicalId":170034,"journal":{"name":"Workshop on Optical Fabrication and Testing","volume":"28 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":"126241399","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 manufacture of precision optical surfaces by diamond machining requires a high quality diamond tool, a low vibration, high precision machine, .a stable environment and rigorous machining practices. A view of a diamond turning machine at the Oak Ridge Y-12 Plant(a) is shown in Figure 1. This type of machine is being used.to produce optical surfaces on mirrors such as shown in Figure 2. This mirror, having dimensions as shown in Figure 3, is machined by turning about the mirror centroid. As with any machining process, the technique used to hold the part during machining is critical when trying to achieve an accurate contour. Part–holding errors can arise from centrifugal forces, part motion with respect to the fixture, or distortions introduced into the part by the fixture. A good fixturing technique will minimize these errors but must not be too cumbersome.
{"title":"Part Support Studies for Diamond Machining Mirrors","authors":"S. Robinson, H. Gerth, J. Stoneking","doi":"10.1364/oft.1979.mo17","DOIUrl":"https://doi.org/10.1364/oft.1979.mo17","url":null,"abstract":"The manufacture of precision optical surfaces by diamond machining requires a high quality diamond tool, a low vibration, high precision machine, .a stable environment and rigorous machining practices. A view of a diamond turning machine at the Oak Ridge Y-12 Plant(a) is shown in Figure 1. This type of machine is being used.to produce optical surfaces on mirrors such as shown in Figure 2. This mirror, having dimensions as shown in Figure 3, is machined by turning about the mirror centroid. As with any machining process, the technique used to hold the part during machining is critical when trying to achieve an accurate contour. Part–holding errors can arise from centrifugal forces, part motion with respect to the fixture, or distortions introduced into the part by the fixture. A good fixturing technique will minimize these errors but must not be too cumbersome.","PeriodicalId":170034,"journal":{"name":"Workshop on Optical Fabrication and Testing","volume":"37 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":"121440501","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}
Moire deflectometry1,2 provides a viable alternative to interferometry for the measurement of ray deflections from a phase object. Being an incoherent technique it is free from stability problems associated with interferometry. Among the other advantages is the simplicity of the setup and use of low quality optics.
{"title":"Moire Deflectometry Utilizing \"ZYGO\" Automatic Pattern Processor System","authors":"D. Sharma, C. Delisle","doi":"10.1364/oft.1986.tha6","DOIUrl":"https://doi.org/10.1364/oft.1986.tha6","url":null,"abstract":"Moire deflectometry1,2 provides a viable alternative to interferometry for the measurement of ray deflections from a phase object. Being an incoherent technique it is free from stability problems associated with interferometry. Among the other advantages is the simplicity of the setup and use of low quality optics.","PeriodicalId":170034,"journal":{"name":"Workshop on 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":"122962633","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}
Surface irregularities range in lateral dimensions from those usually associated with optical figure error through values associated with zonal errors to those usually described as microroughness and extending to submicron dimensions. Typically, the irregularities are a small fraction of a wavelength in height so that physical, not geometrical, optics must be used to calculate their contribution to optical performance. The total integrated scatter (TIS) from irregularities is given by the expression (4πδ/λ)2, where λ is the wavelength and δ is the rms roughness of the surface. TIS is defined as the total reflectance of the surface minus the specular reflectance, i.e., the fraction of the total reflected light that is scattered into a hemisphere. The amount of scattered light is proportional to the mean square of the heights of the surface irregularities. No upper limiting value of lateral dimensions of the surface irregularities appears in this scalar theory, although, for normal incidence, the scattering becomes virtual when the lateral dimension ℓ of the irregularities becomes less than λ. The more closely spaced the irregularities are, the larger is the angle into which light is scattered. When ℓ ≈ λ, as is true for zonal irregularities, the scattered light is very close to the specular direction (typically a few minutes of arc), and, for still larger lateral dimensions such as are associated with figure errors, its main effect is to decrease the on-axis intensity of the focused beam. It follows that if near-angle scattering is of primary importance, as for example in a system projecting a light beam, the most important surfacing parameters may be zonal and figure errors. Large-angle scattering may also be important but becomes of particular concern for an imaging system such as a telescope where light may enter the optical system from large off-axis angles, strike the optical component, and be scattered into the focal plane. When large-angle scattering is important, the height of the more closely spaced irregularities beomes critical. A calculation of the effect of microirregularities having a range of autocovariance lengths on the performance of a typical mirror telescope will be given to demonstrate the possible degradation effects of both near- and large-angle scattering. Vignetting effects that occur when the mirror is illuminated at off-axis angles are also considered. (It should be pointed out that we are discussing scattering of light into the optical path by the optical components themselves. No arrangement of baffles will have any effect on this type of scattered intensity. Programs such as APART or GUERAP are designed to prevent light scattered from the mounting system from reaching the focal plane, not light scattered directly into the focal plane by the components themselves.)
{"title":"The Effect of Surface Errors on Optical Performance","authors":"J. Elson, H. E. Bennett","doi":"10.1364/oft.1984.thdc4","DOIUrl":"https://doi.org/10.1364/oft.1984.thdc4","url":null,"abstract":"Surface irregularities range in lateral dimensions from those usually associated with optical figure error through values associated with zonal errors to those usually described as microroughness and extending to submicron dimensions. Typically, the irregularities are a small fraction of a wavelength in height so that physical, not geometrical, optics must be used to calculate their contribution to optical performance. The total integrated scatter (TIS) from irregularities is given by the expression (4πδ/λ)2, where λ is the wavelength and δ is the rms roughness of the surface. TIS is defined as the total reflectance of the surface minus the specular reflectance, i.e., the fraction of the total reflected light that is scattered into a hemisphere. The amount of scattered light is proportional to the mean square of the heights of the surface irregularities. No upper limiting value of lateral dimensions of the surface irregularities appears in this scalar theory, although, for normal incidence, the scattering becomes virtual when the lateral dimension ℓ of the irregularities becomes less than λ. The more closely spaced the irregularities are, the larger is the angle into which light is scattered. When ℓ ≈ λ, as is true for zonal irregularities, the scattered light is very close to the specular direction (typically a few minutes of arc), and, for still larger lateral dimensions such as are associated with figure errors, its main effect is to decrease the on-axis intensity of the focused beam. It follows that if near-angle scattering is of primary importance, as for example in a system projecting a light beam, the most important surfacing parameters may be zonal and figure errors. Large-angle scattering may also be important but becomes of particular concern for an imaging system such as a telescope where light may enter the optical system from large off-axis angles, strike the optical component, and be scattered into the focal plane. When large-angle scattering is important, the height of the more closely spaced irregularities beomes critical. A calculation of the effect of microirregularities having a range of autocovariance lengths on the performance of a typical mirror telescope will be given to demonstrate the possible degradation effects of both near- and large-angle scattering. Vignetting effects that occur when the mirror is illuminated at off-axis angles are also considered. (It should be pointed out that we are discussing scattering of light into the optical path by the optical components themselves. No arrangement of baffles will have any effect on this type of scattered intensity. Programs such as APART or GUERAP are designed to prevent light scattered from the mounting system from reaching the focal plane, not light scattered directly into the focal plane by the components themselves.)","PeriodicalId":170034,"journal":{"name":"Workshop on Optical Fabrication and Testing","volume":"186 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":"116136302","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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