Matthew D. Summers, Robin L. Hibbard, Lisa W. Liou, William F. Mayor, Robert B. Michie
A device has been developed to measure the frequency conversion performance of large aperture potassium dihydrogen phosphate (KDP) crystals. Third harmonic generation using KDP is critical to the function of the National Ignition Facility (NIF) laser. The crystals in the converter can be angularly or thermally tuned but are subject to larger aperture inhomogeneities that are functions of growth, manufacturing and mounting. The CAVE (Crystal Alignment Verification Equipment) instrument scans the crystals in a thermally and mechanically controlled environment to determine the local peak tuning angles. The CAVE can then estimate the optimum tuning angle and conversion efficiency over the entire aperture. Coupled with other metrology techniques, the CAVE will help determine which crystal life-cycle components most affect harmonic conversion.
{"title":"CAVE: The Design of a Precision Metrology Instrument for Studying Performance of KDP Crystals","authors":"Matthew D. Summers, Robin L. Hibbard, Lisa W. Liou, William F. Mayor, Robert B. Michie","doi":"10.1364/oft.1998.otub.2","DOIUrl":"https://doi.org/10.1364/oft.1998.otub.2","url":null,"abstract":"A device has been developed to measure the frequency conversion performance of large aperture potassium dihydrogen phosphate (KDP) crystals. Third harmonic generation using KDP is critical to the function of the National Ignition Facility (NIF) laser. The crystals in the converter can be angularly or thermally tuned but are subject to larger aperture inhomogeneities that are functions of growth, manufacturing and mounting. The CAVE (Crystal Alignment Verification Equipment) instrument scans the crystals in a thermally and mechanically controlled environment to determine the local peak tuning angles. The CAVE can then estimate the optimum tuning angle and conversion efficiency over the entire aperture. Coupled with other metrology techniques, the CAVE will help determine which crystal life-cycle components most affect harmonic conversion.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126701917","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 key design challenge for the National Ignition Facility (NIF), being constructed at Lawrence Livermore National Laboratory (LLNL), [Hibbard, R. L., 1998], is the frequency converter consisting of two KDP crystals and a focusing lens. Frequency conversion is a critical performance factor for NIF and the optical mount design for this plays a key role in meeting design specifications. The frequency converter, Figure 1, is a monolithic cell that mounts the optics and is the point on the beamline where the frequency conversion crystals are optimally aligned and the cell is focused on target. The lasing medium is neodymium in phosphate glass with a fundamental frequency (1ω) of 1.053 µm. Sum frequency generation in a pair of conversion crystals (KDP/KD*P) produces 1.8 MJ of the third harmonic light (3ω or λ=0.35 µm). The phase-matching scheme on NIF is type I second harmonic generation followed by type II sum-frequency-mixing of the residual fundamental and the second harmonic light. This laser unlike previous laser system designs, must achieve high conversion efficiency, 85%, which is close to the 90.8% theoretical maximum. As a result, this design is very sensitive to angular variations in beam propagation and in the crystal axes orientation. Factors that influence the phase matching angle include crystal inhomogeneity, residual and induced stress in the crystals, the crystals’ natural and mounted surface figure, mounting imperfections and gravity sag. These angular variations need to be controlled within a 40 µrad error budget. The optical mount contributions to the angular error budget are 20 µrad and are what make the frequency converter in the Final Optics Cell (FOC) such a challenging precision design.
{"title":"The Design of Precision Mounts for Optimizing the Conversion Efficiency of KDP Crystals for the National Ignition Facility*","authors":"Robin L. Hibbard, Mary A. Norton, Paul J. Wegner","doi":"10.1364/oft.1998.otuc.6","DOIUrl":"https://doi.org/10.1364/oft.1998.otuc.6","url":null,"abstract":"A key design challenge for the National Ignition Facility (NIF), being constructed at Lawrence Livermore National Laboratory (LLNL), [Hibbard, R. L., 1998], is the frequency converter consisting of two KDP crystals and a focusing lens. Frequency conversion is a critical performance factor for NIF and the optical mount design for this plays a key role in meeting design specifications. The frequency converter, Figure 1, is a monolithic cell that mounts the optics and is the point on the beamline where the frequency conversion crystals are optimally aligned and the cell is focused on target. The lasing medium is neodymium in phosphate glass with a fundamental frequency (1ω) of 1.053 µm. Sum frequency generation in a pair of conversion crystals (KDP/KD*P) produces 1.8 MJ of the third harmonic light (3ω or λ=0.35 µm). The phase-matching scheme on NIF is type I second harmonic generation followed by type II sum-frequency-mixing of the residual fundamental and the second harmonic light. This laser unlike previous laser system designs, must achieve high conversion efficiency, 85%, which is close to the 90.8% theoretical maximum. As a result, this design is very sensitive to angular variations in beam propagation and in the crystal axes orientation. Factors that influence the phase matching angle include crystal inhomogeneity, residual and induced stress in the crystals, the crystals’ natural and mounted surface figure, mounting imperfections and gravity sag. These angular variations need to be controlled within a 40 µrad error budget. The optical mount contributions to the angular error budget are 20 µrad and are what make the frequency converter in the Final Optics Cell (FOC) such a challenging precision design.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127925068","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}
Robin L. Hibbard, R. E. English, Jim J. De Yoreo, R. Montesanti
The National Ignition Facility (NIF), being constructed at Lawrence Livermore National Laboratory (LLNL), comprises 192 laser beams, Figure 1. The lasing medium is neodymium in phosphate glass with a fundamental frequency (1ω) of 1.053 µm. Sum frequency generation in a pair of conversion crystals (KDP/KD*P) produces 1.8 MJ of the third harmonic light (3ω or λ =0.35 µm). On NIF the frequency conversion crystals are part of the Final Optics Assembly (FOA), whose two principal functions are to convert the laser light to 3ω and focus it on target. In addition, the FOA provides a vacuum window to the target chamber, smoothes the on-target irradiance profile, moves the unconverted light away from the target, and provides signals for alignment and diagnostics. The FOA has four Integrated Optics Modules (IOM), Figure 4, each of which contains two 41 cm square crystals are mounted with the full edge support to micro radian angular and micron flatness tolerances. This paper is intended to be an overview of the important factors that affect frequency conversion on NIF. Chief among these are angular errors arising from crystal growth, finishing, and mounting. The general nature of these errors and how they affect frequency conversion, and finally the importance of a frequency conversion metrology tool in assessing converter performance before opto-mechanical assemblies are installed on NIF will be discussed.
{"title":"Frequency Converter Design and Manufacturing Considerations for the National Ignition Facility*","authors":"Robin L. Hibbard, R. E. English, Jim J. De Yoreo, R. Montesanti","doi":"10.1364/oft.1998.otub.3","DOIUrl":"https://doi.org/10.1364/oft.1998.otub.3","url":null,"abstract":"The National Ignition Facility (NIF), being constructed at Lawrence Livermore National Laboratory (LLNL), comprises 192 laser beams, Figure 1. The lasing medium is neodymium in phosphate glass with a fundamental frequency (1ω) of 1.053 µm. Sum frequency generation in a pair of conversion crystals (KDP/KD*P) produces 1.8 MJ of the third harmonic light (3ω or λ =0.35 µm).\u0000 On NIF the frequency conversion crystals are part of the Final Optics Assembly (FOA), whose two principal functions are to convert the laser light to 3ω and focus it on target. In addition, the FOA provides a vacuum window to the target chamber, smoothes the on-target irradiance profile, moves the unconverted light away from the target, and provides signals for alignment and diagnostics. The FOA has four Integrated Optics Modules (IOM), Figure 4, each of which contains two 41 cm square crystals are mounted with the full edge support to micro radian angular and micron flatness tolerances.\u0000 This paper is intended to be an overview of the important factors that affect frequency conversion on NIF. Chief among these are angular errors arising from crystal growth, finishing, and mounting. The general nature of these errors and how they affect frequency conversion, and finally the importance of a frequency conversion metrology tool in assessing converter performance before opto-mechanical assemblies are installed on NIF will be discussed.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125475627","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}
Over the past several years much concern has been voiced about the lack of trained technologists to support high-technology industry and manufacturing in the United States. Attracting and training both new members and upgrading and retraining current members of this area of the workforce has many challenges to address before adequate numbers of well trained individuals will be available to fill the growing demand and help secure our nation’s economic industrial edge. Among the concerns are the lack of effective training programs, available funding, career image, and vehicles to educate the public on the availability of positions and excellent rate of compensation. These concerns which effect many areas of industrial manufacturing have been highlighted by government organizations, such as the Department of Labor statistics, and professional journals and publications. In the specific area of optical fabrication, journals such as “Laser Focus: and Photonics Spectra” have dedicated articles and editorials discussing the lack of optical fabrication training resources in the United States. Examples of other vocational areas lacking skilled workers, such as precision machinists, are reflected in articles in other publications such as “Manufacturing Engineering”.
{"title":"Education and Training in Optics Fabrication: Establishing unique partnerships to address workforce training needs for optics and other high technology manufacturing","authors":"K. Kiernan","doi":"10.1364/oft.1998.otua.6","DOIUrl":"https://doi.org/10.1364/oft.1998.otua.6","url":null,"abstract":"Over the past several years much concern has been voiced about the lack of trained technologists to support high-technology industry and manufacturing in the United States. Attracting and training both new members and upgrading and retraining current members of this area of the workforce has many challenges to address before adequate numbers of well trained individuals will be available to fill the growing demand and help secure our nation’s economic industrial edge. Among the concerns are the lack of effective training programs, available funding, career image, and vehicles to educate the public on the availability of positions and excellent rate of compensation. These concerns which effect many areas of industrial manufacturing have been highlighted by government organizations, such as the Department of Labor statistics, and professional journals and publications. In the specific area of optical fabrication, journals such as “Laser Focus: and Photonics Spectra” have dedicated articles and editorials discussing the lack of optical fabrication training resources in the United States. Examples of other vocational areas lacking skilled workers, such as precision machinists, are reflected in articles in other publications such as “Manufacturing Engineering”.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"191 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116388492","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}
Lawrence Livermore National Laboratory is in the process of constructing the National Ignition Facility, a half million square foot facility which will house a 192 beam laser system capable of generating the 2 million joules of ultraviolet light energy necessary to achieve fusion ignition with inertial targets by 2004. More than 7,000 meter class optics will need to be manufactured by LLNL’s industrial partners to construct the laser system1. The components will be manufactured starting in 1998 and will be finished by 2003.
{"title":"Developing enabling optics finishing technologies for the National Ignition Facility","authors":"D. Aikens, L. Rich, D. Bajuk, A. Slomba","doi":"10.1364/oft.1998.otub.1","DOIUrl":"https://doi.org/10.1364/oft.1998.otub.1","url":null,"abstract":"Lawrence Livermore National Laboratory is in the process of constructing the National Ignition Facility, a half million square foot facility which will house a 192 beam laser system capable of generating the 2 million joules of ultraviolet light energy necessary to achieve fusion ignition with inertial targets by 2004. More than 7,000 meter class optics will need to be manufactured by LLNL’s industrial partners to construct the laser system1. The components will be manufactured starting in 1998 and will be finished by 2003.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"424 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127604038","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}
B. Bernacki, Arthur C. Miller, B. Evans, W. Moreshead, J. Nogues
Deterministic optics manufacturing, notably single point diamond turning (SPDT) has matured such that the current generation of machines1 is capable of producing refractive and reflective optics for the visible wavelength region that are quite acceptable for many applications.2 However, spiral tool marks are still produced that result in unwanted diffractive scattering from grating-like features having a spatial frequency determined by the machine feed, tool radius, and other influences such as vibration and material removal effects. Such regular artifacts are the characteristic of deterministic manufacturing methods such as SPDT.
{"title":"Sol-Gel Replicated Optics Made From Single Point Diamond Turned Masters Exhibit Fractal Surface Roughness","authors":"B. Bernacki, Arthur C. Miller, B. Evans, W. Moreshead, J. Nogues","doi":"10.1364/oft.1996.owb.4","DOIUrl":"https://doi.org/10.1364/oft.1996.owb.4","url":null,"abstract":"Deterministic optics manufacturing, notably single point diamond turning (SPDT) has matured such that the current generation of machines1 is capable of producing refractive and reflective optics for the visible wavelength region that are quite acceptable for many applications.2 However, spiral tool marks are still produced that result in unwanted diffractive scattering from grating-like features having a spatial frequency determined by the machine feed, tool radius, and other influences such as vibration and material removal effects. Such regular artifacts are the characteristic of deterministic manufacturing methods such as SPDT.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117116856","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}
Smooth surface topography (finish) has been related, almost exactly, to the corresponding reflected scatter pattern under the condition that the sample is a smooth, clean, front surface reflector [1-3]. However, another extremely useful application of light scatter metrology is the detection and mapping of component defects that do not meet the smooth, clean, reflective conditions of many mirror surfaces. Examples of such defects are surface contaminants, deep scratches and digs, coating globs and residues, and subsurface defects. When detecting the presence of these defects by scatter measurement, the surface topography scatter is a limiting source of noise. Although smooth non-topographic defects often scatter more light than the surrounding surface topography, they may sometimes scatter considerably less light because they have a small cross-sectional area or because they are buried just beneath a reflective surface. In such cases, a low signal to noise ratio results. If it can be established that non-topographic defects scatter light differently than surface topography, then these differences can be exploited to improve signal to noise and map the defects using various raster techniques described in the literature. This paper discusses polarization differences in topographic and defect scatter and outlines techniques that have been used to enhance defect detection.
{"title":"Detection of Discrete Surface and Subsurface Defects","authors":"J. Stover","doi":"10.1117/3.203079.CH8","DOIUrl":"https://doi.org/10.1117/3.203079.CH8","url":null,"abstract":"Smooth surface topography (finish) has been related, almost exactly, to the corresponding reflected scatter pattern under the condition that the sample is a smooth, clean, front surface reflector [1-3]. However, another extremely useful application of light scatter metrology is the detection and mapping of component defects that do not meet the smooth, clean, reflective conditions of many mirror surfaces. Examples of such defects are surface contaminants, deep scratches and digs, coating globs and residues, and subsurface defects. When detecting the presence of these defects by scatter measurement, the surface topography scatter is a limiting source of noise. Although smooth non-topographic defects often scatter more light than the surrounding surface topography, they may sometimes scatter considerably less light because they have a small cross-sectional area or because they are buried just beneath a reflective surface. In such cases, a low signal to noise ratio results. If it can be established that non-topographic defects scatter light differently than surface topography, then these differences can be exploited to improve signal to noise and map the defects using various raster techniques described in the literature. This paper discusses polarization differences in topographic and defect scatter and outlines techniques that have been used to enhance defect detection.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115946568","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 LLNL, Zygo (mod 5500), WYKO (Topo - 2 D, Topo - 3 D), and Photographic Sciences (MP-2000), non contact optical profilers were compared and found consistent within their common band limits.
{"title":"Some Comparisons of Non Contact Surface Profiling Instruments","authors":"N. J. Brown, W. Eickelberg","doi":"10.1364/oft.1988.tha1","DOIUrl":"https://doi.org/10.1364/oft.1988.tha1","url":null,"abstract":"The LLNL, Zygo (mod 5500), WYKO (Topo - 2 D, Topo - 3 D), and Photographic Sciences (MP-2000), non contact optical profilers were compared and found consistent within their common band limits.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1988-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127511185","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 tutorial will explore the process of establishing the specifications for optical components. It is intended to help the Optical Shop Supervisor or Process Engineer gain a better understanding of the reasons behind the specifications sent to the shop by the designers. The factors considered by the Optical Designer and Engineer in selecting materials, finishes, and tolerances, as well as the consequence of excessive variance from specification.
{"title":"Optical Shop Specifications","authors":"K. Walsh","doi":"10.1364/oft.1990.owa1","DOIUrl":"https://doi.org/10.1364/oft.1990.owa1","url":null,"abstract":"This tutorial will explore the process of establishing the specifications for optical components. It is intended to help the Optical Shop Supervisor or Process Engineer gain a better understanding of the reasons behind the specifications sent to the shop by the designers. The factors considered by the Optical Designer and Engineer in selecting materials, finishes, and tolerances, as well as the consequence of excessive variance from specification.","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"11 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":"114999092","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}
Because of the complicated interactions between the tool and workpiece during the grinding process, tool topography is a useful resource for understanding the process [1-2]. Issues that can be understood by tool topography include: overall wheel surface profile, abrasive concentration on the wheel surface, effective number of cutting points, fracture and debonding of abrasives, protrusion height of abrasives, and tool wear mechanisms [2-7].
{"title":"Assessment of Microgrinding Tool Topography Using Optical Profilometry","authors":"Yi-yang Zhou, D. Quesnel, P. Funkenbusch","doi":"10.1364/oft.1996.ofa.6","DOIUrl":"https://doi.org/10.1364/oft.1996.ofa.6","url":null,"abstract":"Because of the complicated interactions between the tool and workpiece during the grinding process, tool topography is a useful resource for understanding the process [1-2]. Issues that can be understood by tool topography include: overall wheel surface profile, abrasive concentration on the wheel surface, effective number of cutting points, fracture and debonding of abrasives, protrusion height of abrasives, and tool wear mechanisms [2-7].","PeriodicalId":354934,"journal":{"name":"Optical Fabrication and Testing","volume":"207 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":"114665731","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：