2016
Alonso, Miguel A.; Forbes, G. W.
Strehl ratio as the Fourier transform of a probability density of error differences Journal Article
In: Optics Letters, vol. 41, no. 16, pp. 3735-3738, 2016.
Abstract | Links | BibTeX | Tags: CeFO, Mid-Spatial Frequency error, Strehl ratio
@article{Alonso2016,
title = {Strehl ratio as the Fourier transform of a probability density of error differences},
author = {Miguel A. Alonso and G.W. Forbes},
editor = {OSA},
doi = {10.1364/OL.41.003735},
year = {2016},
date = {2016-08-04},
urldate = {2016-08-04},
journal = {Optics Letters},
volume = {41},
number = {16},
pages = {3735-3738},
abstract = {To give useful insight into the impact of mid-spatial frequency structure on optical performance, the Strehl ratio is shown to correspond to the Fourier transform of a simple statistical characterization of the aberration in the exit pupil. This statistical description is found simply by autocorrelating a histogram of the aberration values. In practice, the histogram itself can often be approximated by a convolution of underlying histograms associated with fabrication steps and, together with the final autocorrelation, it follows from the central limit theorem that the Strehl ratio as a function of the scale of the phase error is generally approximated well by a Gaussian.},
keywords = {CeFO, Mid-Spatial Frequency error, Strehl ratio},
pubstate = {published},
tppubtype = {article}
}
To give useful insight into the impact of mid-spatial frequency structure on optical performance, the Strehl ratio is shown to correspond to the Fourier transform of a simple statistical characterization of the aberration in the exit pupil. This statistical description is found simply by autocorrelating a histogram of the aberration values. In practice, the histogram itself can often be approximated by a convolution of underlying histograms associated with fabrication steps and, together with the final autocorrelation, it follows from the central limit theorem that the Strehl ratio as a function of the scale of the phase error is generally approximated well by a Gaussian.
Owen, J.; Troutman, J.; Harriman, T.; Zare, A.; Wang, Y.; Lucca, D.; Davies, M.
The mechanics of milling of germanium for IR applications Journal Article
In: CIRP Annals - Manufacturing Technology, vol. 65, no. 1, 2016.
Abstract | BibTeX | Tags: CeFO, manufacturing
@article{MDavies2,
title = {The mechanics of milling of germanium for IR applications},
author = {Owen, J. and J. Troutman and T. Harriman and A. Zare and Y. Wang and D. Lucca and M. Davies},
year = {2016},
date = {2016-08-01},
journal = {CIRP Annals - Manufacturing Technology},
volume = {65},
number = {1},
abstract = {Freeform germanium optics produced by single crystal diamond milling are important for infrared (IR) imaging applications. However the mechanics of interrupted cutting of germanium is not fully understood. This paper presents new findings from cutting experiments including: (1) uninterrupted orthogonal cutting and (2) interrupted flycutting of germanium. Forces are measured and the cutting mechanics are correlated with surface and subsurface measurements performed with: (1) atomic force microscopy, (2) confocal Raman spectroscopy, and (3) channeling Rutherford backscattering spectrometry. These fundamental results guide parameter choice for more complex freeform ball milling of optics for IR applications ranging from surveillance to medical imaging.},
keywords = {CeFO, manufacturing},
pubstate = {published},
tppubtype = {article}
}
Freeform germanium optics produced by single crystal diamond milling are important for infrared (IR) imaging applications. However the mechanics of interrupted cutting of germanium is not fully understood. This paper presents new findings from cutting experiments including: (1) uninterrupted orthogonal cutting and (2) interrupted flycutting of germanium. Forces are measured and the cutting mechanics are correlated with surface and subsurface measurements performed with: (1) atomic force microscopy, (2) confocal Raman spectroscopy, and (3) channeling Rutherford backscattering spectrometry. These fundamental results guide parameter choice for more complex freeform ball milling of optics for IR applications ranging from surveillance to medical imaging.
Troutman, J. R.; Barnhardt, D.; Shultz, J.; Owen, J. D.; Davies, M. A.; Suleski, T. J.
Machining and metrology of a chalcogenide glass lens pair Journal Article Forthcoming
In: Procedia Manufacturing, Forthcoming.
BibTeX | Tags: CeFO, manufacturing
@article{Davies16_3,
title = {Machining and metrology of a chalcogenide glass lens pair},
author = {Troutman, J. R. and D. Barnhardt and J. Shultz and J.D. Owen and M.A. Davies and T.J. Suleski},
year = {2016},
date = {2016-06-30},
journal = {Procedia Manufacturing},
keywords = {CeFO, manufacturing},
pubstate = {forthcoming},
tppubtype = {article}
}
Troutman, J.; Barnhardt, D. L.; Shultz, J.; Owen, J.; DeFisher, S.; Davies, M.; Suleski, T.
Slow Tool Servo Machining and Metrology of a Chalcogenide Glass Freeform Lens Pair Journal Article
In: Transactions of NAMRI/SME, vol. 44, no. 1, 2016.
Abstract | BibTeX | Tags: CeFO, manufacturing
@article{Mdavies3,
title = {Slow Tool Servo Machining and Metrology of a Chalcogenide Glass Freeform Lens Pair},
author = {Troutman, J. and D. L. Barnhardt and J. Shultz and J. Owen and S. DeFisher and M. Davies and T. Suleski},
year = {2016},
date = {2016-06-27},
journal = {Transactions of NAMRI/SME},
volume = {44},
number = {1},
abstract = {Slow tool servo remains a preferred method for ultraprecision manufacture of freeform optics with millimeter-scale departures from an axisymmetric surface. A methodology has been developed for pre-process mapping of, and compensation for, predictable error sources such as tool waviness and machine misalignment, reducing necessity for typical post-process workpiece error correction procedures. This methodology is implemented for manufacture of a chalcogenide glass freeform lens pair for a variable-focus thermal imaging application. Process development, part metrology, and system functional testing are presented.},
keywords = {CeFO, manufacturing},
pubstate = {published},
tppubtype = {article}
}
Slow tool servo remains a preferred method for ultraprecision manufacture of freeform optics with millimeter-scale departures from an axisymmetric surface. A methodology has been developed for pre-process mapping of, and compensation for, predictable error sources such as tool waviness and machine misalignment, reducing necessity for typical post-process workpiece error correction procedures. This methodology is implemented for manufacture of a chalcogenide glass freeform lens pair for a variable-focus thermal imaging application. Process development, part metrology, and system functional testing are presented.
Shahinian, H.; Mullany, B.
Optical Polishing Using Fiber Based Tools Conference
2016.
BibTeX | Tags: CeFO, manufacturing
@conference{Shaninian16,
title = {Optical Polishing Using Fiber Based Tools},
author = {Shahinian, H. and B. Mullany},
editor = {Procedia CIRP},
year = {2016},
date = {2016-06-10},
keywords = {CeFO, manufacturing},
pubstate = {published},
tppubtype = {conference}
}
Schiesser, Eric M.; Rolland, J. P.
Sensitivity analysis comparison of unobscured TMA: freeform vs. co-axial Conference
2016, (Mirror Tech Days ).
@conference{Schiesser2016b,
title = {Sensitivity analysis comparison of unobscured TMA: freeform vs. co-axial},
author = {Eric M. Schiesser and J.P. Rolland},
year = {2016},
date = {2016-04-01},
note = {Mirror Tech Days },
keywords = {CeFO, design},
pubstate = {published},
tppubtype = {conference}
}
Bauer, A.; Rolland, J. P.; Thompson, K. P.
Ray-based optical design tool for freeform optics: coma full-field display Journal Article
In: Opt. Express, vol. 24, no. 1, pp. 459-472, 2016.
@article{BAUER16a,
title = {Ray-based optical design tool for freeform optics: coma full-field display},
author = {Bauer, A. and J. P. Rolland and K. P. Thompson},
year = {2016},
date = {2016-01-07},
journal = {Opt. Express},
volume = {24},
number = {1},
pages = {459-472},
keywords = {CeFO, design},
pubstate = {published},
tppubtype = {article}
}
Troutman, J. R.; Owen, J. D.; Zare, A.; Harriman, T. A.; Lucca, D. A.; Davies, M. A.
Cutting Mechanics and Subsurface Integrity in Diamond Machining of Chalcogenide Glass Journal Article
In: Procedia CIRP, vol. 45, pp. 135–138, 2016.
Abstract | Links | BibTeX | Tags: CeFO, manufacturing
@article{Davies16_2,
title = {Cutting Mechanics and Subsurface Integrity in Diamond Machining of Chalcogenide Glass},
author = {Troutman, J.R. and J. D. Owen and A. Zare and T. A. Harriman and D. A. Lucca and M. A. Davies},
url = {http://www.sciencedirect.com/science/article/pii/S2212827116006788},
doi = {doi: 10.1016/j.procir.2016.03.020 },
year = {2016},
date = {2016-00-00},
journal = {Procedia CIRP},
volume = {45},
pages = {135–138},
abstract = {Infrared-transparent chalcogenide glasses are important for the manufacturing of optics for thermal imaging. These brittle materials can be diamond machined, but material removal rates are often limited by the occurrence of surface/subsurface damage. In this paper, the cutting mechanics of orthogonal cutting, orthogonal flycutting and ball-milling of a common chalcogenide glass (As40Se60) are measured and analyzed. The nature of the resulting surface/subsurface was characterized with atomic force microscopy, Raman spectroscopy, and nanoindentation. Results of this study contribute to both the fundamental understanding of material behavior and the cost-effective production of novel freeform infrared optics.},
keywords = {CeFO, manufacturing},
pubstate = {published},
tppubtype = {article}
}
Infrared-transparent chalcogenide glasses are important for the manufacturing of optics for thermal imaging. These brittle materials can be diamond machined, but material removal rates are often limited by the occurrence of surface/subsurface damage. In this paper, the cutting mechanics of orthogonal cutting, orthogonal flycutting and ball-milling of a common chalcogenide glass (As40Se60) are measured and analyzed. The nature of the resulting surface/subsurface was characterized with atomic force microscopy, Raman spectroscopy, and nanoindentation. Results of this study contribute to both the fundamental understanding of material behavior and the cost-effective production of novel freeform infrared optics.
2015
Schiesser, Eric M.; Papa, Jonathan C.; Thompson, Kevin P.; Rolland, Jannick P.
Tools for Visualizing the Solution Space for Freeform Three-Mirrors Anastigmats Presentation
10.11.2015, (NASA Mirror/Tech/SBIR/STTR workshop (2015)).
@misc{ShiesserNASA15,
title = {Tools for Visualizing the Solution Space for Freeform Three-Mirrors Anastigmats},
author = {Eric M. Schiesser and Jonathan C. Papa and Kevin P. Thompson and Jannick P. Rolland},
year = {2015},
date = {2015-11-10},
note = {NASA Mirror/Tech/SBIR/STTR workshop (2015)},
keywords = {CeFO, design},
pubstate = {published},
tppubtype = {presentation}
}
Ricci, M. A.; Butler, S. C.; Wang, C.; Ellis, J. D.
3 axis homodyne displacement measuring interferometer probe for freeform optics Conference
Proceedings of the 30th ASPE Annual Meeting, 2015.
@conference{Ricci15,
title = {3 axis homodyne displacement measuring interferometer probe for freeform optics},
author = {Ricci, M. A. and S. C. Butler and C. Wang and J. D. Ellis},
year = {2015},
date = {2015-11-01},
booktitle = {Proceedings of the 30th ASPE Annual Meeting},
keywords = {CeFO, testing},
pubstate = {published},
tppubtype = {conference}
}
Bauer, A.; Rolland, J. P.
Design of a freeform electronic viewfinder coupled to aberration fields of freeform optics Journal Article
In: Optics Express, vol. 23, no. 22, pp. 28141-28153, 2015.
@article{Bauer15,
title = {Design of a freeform electronic viewfinder coupled to aberration fields of freeform optics},
author = {Bauer, A. and J. P. Rolland},
year = {2015},
date = {2015-10-19},
journal = {Optics Express},
volume = {23},
number = {22},
pages = {28141-28153},
keywords = {CeFO, design},
pubstate = {published},
tppubtype = {article}
}
Butler, S. C.; Ricci, M. A.; Wang, C.; Wei, Q.; Ellis, J. D.
Homodyne displacement measuring interferometer probe for optical Conference
SPIE OptiFab 2015, 2015.
@conference{Butler15,
title = {Homodyne displacement measuring interferometer probe for optical},
author = {Butler, S. C. and M. A. Ricci and C. Wang and Q. Wei and J. D. Ellis},
year = {2015},
date = {2015-10-12},
booktitle = {SPIE OptiFab 2015},
keywords = {CeFO, testing},
pubstate = {published},
tppubtype = {conference}
}
Bauer, A.; Thompson, K. P.; Rolland, J. P.
Coma full-field display for freeform imaging systems Conference
Optifab 2015, vol. 9633, no. 963316, Proc. of SPIE, 2015, ( Optifab 2015).
Links | BibTeX | Tags: CeFO, design
@conference{Baueroptifab15,
title = {Coma full-field display for freeform imaging systems},
author = {Bauer, A. and K.P. Thompson and J.P. Rolland},
url = {http://dx.doi.org/10.1117/12.2196061},
doi = {10.1117/12.2196061},
year = {2015},
date = {2015-10-11},
booktitle = {Optifab 2015},
volume = {9633},
number = {963316},
publisher = {Proc. of SPIE},
note = { Optifab 2015},
keywords = {CeFO, design},
pubstate = {published},
tppubtype = {conference}
}
Thompson, Kevin P.; Schiesser, Eric M.; Rolland, Jannick P.
Why are freeform telescopes less alignment sensitive than a traditional unobscured TMA? Conference
Proceedings of SPIE, vol. 9633, no. 963317, 2015.
Abstract | Links | BibTeX | Tags: CeFO, design
@conference{Thomponoptifab15a,
title = {Why are freeform telescopes less alignment sensitive than a traditional unobscured TMA?},
author = {Kevin P. Thompson and Eric M. Schiesser and Jannick P. Rolland},
url = {https://doi.org/10.1117/12.2195784},
doi = {10.1117/12.2195784},
year = {2015},
date = {2015-10-11},
booktitle = {Proceedings of SPIE},
volume = {9633},
number = {963317},
abstract = {As freeform optical systems emerge as interesting and innovative solutions for imaging in 3D packages there is an assumption they are going to be more sensitive particularly at assembly. While it is true that the clocking of the component becomes a relatively weak new tolerance, for the most effective new class of freeform systems the alignment sensitivity is actually lower in most cases than for a comparable traditional unobscured three mirror anastigmatic (TMA) telescope.
Traditional unobscured TMA telescopes, whose designs emerged in the mid-70s and which begin to appear as hardware in the literature in the early 90s, are based on using increasingly offset apertures with otherwise coaxial rotationally symmetric mirrors. The mirrors (typically 3 to correct spherical, coma, and astigmatism) have evolved to contain more high order terms as the designs are pushed to more compact and wider field packages – the NIRCAM camera for the JWST is an excellent example of this [1]. As the higher order terms are added, the mirrors become increasingly sensitive to decenters and tilts.
An emerging class of freeform telescopes that provide wider field of view and/or faster f/numbers than the traditional TMA are based on a strategy where the surface shape remains a low order Zernike-type surface even in compact, unobscured packages. This optical design strategy results in an optical form that is not only higher performance but simultaneously less sensitive to alignment.},
keywords = {CeFO, design},
pubstate = {published},
tppubtype = {conference}
}
As freeform optical systems emerge as interesting and innovative solutions for imaging in 3D packages there is an assumption they are going to be more sensitive particularly at assembly. While it is true that the clocking of the component becomes a relatively weak new tolerance, for the most effective new class of freeform systems the alignment sensitivity is actually lower in most cases than for a comparable traditional unobscured three mirror anastigmatic (TMA) telescope.
Traditional unobscured TMA telescopes, whose designs emerged in the mid-70s and which begin to appear as hardware in the literature in the early 90s, are based on using increasingly offset apertures with otherwise coaxial rotationally symmetric mirrors. The mirrors (typically 3 to correct spherical, coma, and astigmatism) have evolved to contain more high order terms as the designs are pushed to more compact and wider field packages – the NIRCAM camera for the JWST is an excellent example of this [1]. As the higher order terms are added, the mirrors become increasingly sensitive to decenters and tilts.
An emerging class of freeform telescopes that provide wider field of view and/or faster f/numbers than the traditional TMA are based on a strategy where the surface shape remains a low order Zernike-type surface even in compact, unobscured packages. This optical design strategy results in an optical form that is not only higher performance but simultaneously less sensitive to alignment.
Traditional unobscured TMA telescopes, whose designs emerged in the mid-70s and which begin to appear as hardware in the literature in the early 90s, are based on using increasingly offset apertures with otherwise coaxial rotationally symmetric mirrors. The mirrors (typically 3 to correct spherical, coma, and astigmatism) have evolved to contain more high order terms as the designs are pushed to more compact and wider field packages – the NIRCAM camera for the JWST is an excellent example of this [1]. As the higher order terms are added, the mirrors become increasingly sensitive to decenters and tilts.
An emerging class of freeform telescopes that provide wider field of view and/or faster f/numbers than the traditional TMA are based on a strategy where the surface shape remains a low order Zernike-type surface even in compact, unobscured packages. This optical design strategy results in an optical form that is not only higher performance but simultaneously less sensitive to alignment.
Owen, J.; Davies, M.; Schmidt, D.; Urruti, E.
On the ultra-precision diamond machining of chalcogenide glass Journal Article
In: CIRP Annals - Manufacturing Technology, vol. 64, no. 1, pp. 113-116, 2015, ISSN: 0007-8506.
Abstract | Links | BibTeX | Tags: CeFO, manufacturing
@article{madavies15,
title = {On the ultra-precision diamond machining of chalcogenide glass },
author = {Owen, J. and M. Davies and D. Schmidt and E. Urruti },
url = {http://www.sciencedirect.com/science/article/pii/S0007850615000736},
doi = {10.1016/j.cirp.2015.04.065},
issn = {0007-8506},
year = {2015},
date = {2015-08-21},
journal = {CIRP Annals - Manufacturing Technology},
volume = {64},
number = {1},
pages = {113-116},
abstract = {Chalcogenide glasses are important materials for components in thermal imaging systems (IR-optics). While suitable for molding, the machining characteristics of these brittle materials are largely unknown. In this paper, ultra-precision machining data for a common chalcogenide glass (As40Se60) is presented. Data acquired from orthogonal cutting experiments show a transition in cutting mechanics at an uncut chip thickness of approximately one micrometer. This data is used to identify parameters for high-speed milling, and results are used to produce a thermal imaging lens. This paper demonstrates that the milling process is suitable for prototyping and low-batch production of IR-optics in this glass. },
keywords = {CeFO, manufacturing},
pubstate = {published},
tppubtype = {article}
}
Chalcogenide glasses are important materials for components in thermal imaging systems (IR-optics). While suitable for molding, the machining characteristics of these brittle materials are largely unknown. In this paper, ultra-precision machining data for a common chalcogenide glass (As40Se60) is presented. Data acquired from orthogonal cutting experiments show a transition in cutting mechanics at an uncut chip thickness of approximately one micrometer. This data is used to identify parameters for high-speed milling, and results are used to produce a thermal imaging lens. This paper demonstrates that the milling process is suitable for prototyping and low-batch production of IR-optics in this glass.
Chen, Z.
Design and Illumination for a Czerny-Turner Spectrometer Masters Thesis
2015.
@mastersthesis{Chen,
title = {Design and Illumination for a Czerny-Turner Spectrometer},
author = {Chen, Z.},
year = {2015},
date = {2015-07-15},
keywords = {CeFO, design},
pubstate = {published},
tppubtype = {mastersthesis}
}
Butler, S. C.; Ricci, M. A.; Yu, X.; Ellis, J. D.
OCMM Displacement Measuring Interferometer Probe with 3-DoF Measurement Conference
OSA Imaging and Applied Optics Congress - Freeform Optics, 2015.
@conference{Butler15b,
title = {OCMM Displacement Measuring Interferometer Probe with 3-DoF Measurement},
author = {Butler, S. C. and M. A. Ricci and X. Yu and J. D. Ellis},
year = {2015},
date = {2015-06-15},
booktitle = {OSA Imaging and Applied Optics Congress - Freeform Optics},
keywords = {CeFO, testing},
pubstate = {published},
tppubtype = {conference}
}
Hosseinimakarem, Z.; Aryan, H.; Davies, A.; Evans, C.
Considering a Zernike polynomial representation for spatial frequency content of optical surfaces Conference
Imaging and Applied Optics 2015, vol. paper FT2B.2, Optical Society of America, 2015, ISBN: 978-1-943580-00-2.
Abstract | BibTeX | Tags: CeFO, testing
@conference{Hosseinimakarem15,
title = {Considering a Zernike polynomial representation for spatial frequency content of optical surfaces},
author = {Hosseinimakarem, Z. and H. Aryan and A. Davies and C. Evans},
isbn = {978-1-943580-00-2},
year = {2015},
date = {2015-06-11},
booktitle = {Imaging and Applied Optics 2015},
volume = {paper FT2B.2},
publisher = {Optical Society of America},
abstract = {In this manuscript we investigate a Zernike polynomial representation for quantifying the mid-spatial frequency (MSF) content of surfaces and how this representation captures certain characteristics of the MSF. Filtering aspect of these polynomials is also explored.},
keywords = {CeFO, testing},
pubstate = {published},
tppubtype = {conference}
}
In this manuscript we investigate a Zernike polynomial representation for quantifying the mid-spatial frequency (MSF) content of surfaces and how this representation captures certain characteristics of the MSF. Filtering aspect of these polynomials is also explored.
Bauer, A.; Rolland, J. P.
Design Process for an All-Reflective Freeform Electronic Viewfinder Conference
Imaging and Applied Optics 2015 OSA Technical Digest, no. FW3B.2 , 2015, (OSA freeform conference June 8-12).
@conference{Bauerosa,
title = {Design Process for an All-Reflective Freeform Electronic Viewfinder},
author = {Bauer, A. and J. P. Rolland},
year = {2015},
date = {2015-06-08},
booktitle = {Imaging and Applied Optics 2015 OSA Technical Digest},
number = {FW3B.2 },
note = {OSA freeform conference June 8-12},
keywords = {CeFO, design},
pubstate = {published},
tppubtype = {conference}
}
Reimers, Jacob; Schiesser, Eric M.; Thompson, K. P.; Whiteaker, K. L.; Yates, D.; Rolland, J. P.
Comparison of Freeform Imaging Spectrometer Design Forms Using Spectral Full-Field Displays Conference
Imaging and Applied Optics 2015 OSA Technical Digest, no. FM3B.3 , 2015.
@conference{Reimersfreeform15,
title = {Comparison of Freeform Imaging Spectrometer Design Forms Using Spectral Full-Field Displays},
author = {Jacob Reimers and Eric M. Schiesser and K. P. Thompson and K. L. Whiteaker and D. Yates and J. P. Rolland},
year = {2015},
date = {2015-06-08},
booktitle = {Imaging and Applied Optics 2015 OSA Technical Digest},
number = {FM3B.3 },
keywords = {CeFO, design},
pubstate = {published},
tppubtype = {conference}
}
Davies, M. A.; Owen, J. D.; Troutman, J. R.; Barnhardt, D. L.; Suleski, T. J.
Ultra-Precision Diamond Machining of Freeform Optics Conference
Imaging and Applied Optics 2015, OSA Technical Digest (online) (Optical Society of America, 2015), 2015, ISBN: 978-1-943580-00-2.
Abstract | Links | BibTeX | Tags: CeFO, manufacturing
@conference{MDavies5,
title = {Ultra-Precision Diamond Machining of Freeform Optics },
author = {Davies, M. A. and J. D. Owen and J. R. Troutman and D. L. Barnhardt and T. J. Suleski},
url = {https://www.osapublishing.org/abstract.cfm?uri=Freeform-2015-FM1B.1},
doi = {10.1364/FREEFORM.2015.FM1B.1},
isbn = {978-1-943580-00-2},
year = {2015},
date = {2015-06-07},
booktitle = {Imaging and Applied Optics 2015, OSA Technical Digest (online) (Optical Society of America, 2015)},
pages = {FM1B.1},
abstract = {Advances in optical simulation software make optimized freeform designs possible, designs that can arbitrarily redirect light in three dimensions. The advantages of freeform optics and/or machining optics integrated with freeform surfaces include: (1) the ability to replace multiple traditional optics with a single freeform; (2) the capability to simultaneously machine an optical surface with precision alignment features; and (3) the capability to accomplish novel optical functions, such as in the Alvarez lens [2]. Applications range across consumer electronics, night vision, surveillance, directed lighting, medical testing, etc. [1]. Ultra-precision diamond machining and freeform milling is one path to the production of freeform optics, particularly for infrared (IR) applications where form and finish requirements are less stringent than for visible light applications. However, manufacturing and metrology challenges are significant. In this paper we address the former, discuss the current state-of-the-art for freeform machining of brittle materials addressing the following challenges: (1) material behavior during cutting; and (2) dominant sources of errors and their correction. We discuss several examples of the machining of freeform optics in IR materials, but the results are transferable to optics operating in other wavelength regimes as well.},
keywords = {CeFO, manufacturing},
pubstate = {published},
tppubtype = {conference}
}
Advances in optical simulation software make optimized freeform designs possible, designs that can arbitrarily redirect light in three dimensions. The advantages of freeform optics and/or machining optics integrated with freeform surfaces include: (1) the ability to replace multiple traditional optics with a single freeform; (2) the capability to simultaneously machine an optical surface with precision alignment features; and (3) the capability to accomplish novel optical functions, such as in the Alvarez lens [2]. Applications range across consumer electronics, night vision, surveillance, directed lighting, medical testing, etc. [1]. Ultra-precision diamond machining and freeform milling is one path to the production of freeform optics, particularly for infrared (IR) applications where form and finish requirements are less stringent than for visible light applications. However, manufacturing and metrology challenges are significant. In this paper we address the former, discuss the current state-of-the-art for freeform machining of brittle materials addressing the following challenges: (1) material behavior during cutting; and (2) dominant sources of errors and their correction. We discuss several examples of the machining of freeform optics in IR materials, but the results are transferable to optics operating in other wavelength regimes as well.
Owen, J. D.
MANUFACTURE OF INFRARED OPTICS IN BRITTLE MATERIALS PhD Thesis
University of North Carolina at Charlotte, 2015.
Abstract | BibTeX | Tags: CeFO, manufacturing, testing
@phdthesis{JOwen1,
title = {MANUFACTURE OF INFRARED OPTICS IN BRITTLE MATERIALS},
author = {Owen, J. D.},
year = {2015},
date = {2015-05-30},
school = {University of North Carolina at Charlotte},
abstract = {Infrared optics are manufactured for many different applications including: thermal imaging, surveillance, night vision, medical, laser machining, laser surgery, etc. Most infrared transparent materials are hard, brittle, or both. Unless special conditions are generated, diamond machining will lead to surfaces dominated by brittle fracture. The overall purpose of this dissertation is to further the state-of-the-art of infrared optics manufacturing. The first piece of this dissertation is to explore the ductile-brittle behavior of two different infrared materials: germanium and IRG 26 (a chalcogenide glass by Schott). These two materials are very useful IR materials: germanium for its high index of refraction and IRG 26 for its low glass transition temperature allowing for easy molding. The cutting mechanics for these materials was experimentally observed during a series of different cutting operations: face turning, planing/ruling, orthogonal turning, and ball milling. Cutting and thrust forces were measured and analyzed for the force coefficients as a function of the cutting parameters. The cutting force coefficients were found to have a significant drop as the cutting mechanics became increasingly brittle with higher chip thicknesses. The reduced cutting forces at more aggressive parameters could lead to a means of rapid prototyping of IR optics. The second piece of this dissertation is to outline a procedure developed to correct tool errors of a diamond ball mill. Two dominate tool shape errors of a ball mill are diamond position and cutting edge irregularity. An artifact based procedure was used to imprint the tool errors on a measureable part. },
keywords = {CeFO, manufacturing, testing},
pubstate = {published},
tppubtype = {phdthesis}
}
Infrared optics are manufactured for many different applications including: thermal imaging, surveillance, night vision, medical, laser machining, laser surgery, etc. Most infrared transparent materials are hard, brittle, or both. Unless special conditions are generated, diamond machining will lead to surfaces dominated by brittle fracture. The overall purpose of this dissertation is to further the state-of-the-art of infrared optics manufacturing. The first piece of this dissertation is to explore the ductile-brittle behavior of two different infrared materials: germanium and IRG 26 (a chalcogenide glass by Schott). These two materials are very useful IR materials: germanium for its high index of refraction and IRG 26 for its low glass transition temperature allowing for easy molding. The cutting mechanics for these materials was experimentally observed during a series of different cutting operations: face turning, planing/ruling, orthogonal turning, and ball milling. Cutting and thrust forces were measured and analyzed for the force coefficients as a function of the cutting parameters. The cutting force coefficients were found to have a significant drop as the cutting mechanics became increasingly brittle with higher chip thicknesses. The reduced cutting forces at more aggressive parameters could lead to a means of rapid prototyping of IR optics. The second piece of this dissertation is to outline a procedure developed to correct tool errors of a diamond ball mill. Two dominate tool shape errors of a ball mill are diamond position and cutting edge irregularity. An artifact based procedure was used to imprint the tool errors on a measureable part.
Rolland, J. P.
A Leap Forward in Optical Systems Presentation
05.05.2015, (Keynote Speech at Applied Optics and Photonics China (AOPC2015), 5-7 May 2015, Beijing China.).
BibTeX | Tags: assembly, CeFO, design, manufacturing, testing
@misc{ROLLANDa,
title = {A Leap Forward in Optical Systems},
author = {Rolland, J. P.},
year = {2015},
date = {2015-05-05},
note = {Keynote Speech at Applied Optics and Photonics China (AOPC2015), 5-7 May 2015, Beijing China.},
keywords = {assembly, CeFO, design, manufacturing, testing},
pubstate = {published},
tppubtype = {presentation}
}
Hosseinimakarem, Z.; Davies, A.; Evans, C.
Mid-spatial frequency specification and characterization for freeform surfaces Conference
Proceedings of the 15th International Conference on Metrology and Properties of Engineering Surfaces, 2015.
@conference{Hosseinimakarem15b,
title = {Mid-spatial frequency specification and characterization for freeform surfaces},
author = {Hosseinimakarem, Z. and A. Davies and C. Evans},
year = {2015},
date = {2015-03-11},
booktitle = {Proceedings of the 15th International Conference on Metrology and Properties of Engineering Surfaces},
keywords = {CeFO, testing},
pubstate = {published},
tppubtype = {conference}
}
Rolland, J. P.
Highlights of a two-parts case study with freeform optics Presentation
23.02.2015, (keynote speech at EPIC workshop Denmark (February 23-24 2015)).
BibTeX | Tags: assembly, CeFO, design, manufacturing
@misc{ROLLANDb,
title = {Highlights of a two-parts case study with freeform optics},
author = {Rolland, J. P.},
year = {2015},
date = {2015-02-23},
note = {keynote speech at EPIC workshop Denmark (February 23-24 2015)},
keywords = {assembly, CeFO, design, manufacturing},
pubstate = {published},
tppubtype = {presentation}
}
2014
Rolland, J. P.
Applications and Challenges with Freeform Optics Presentation
22.06.2014, (Keynote speech at ASPE, (Hawaii, Big Island, 22-26 June 2014)).
BibTeX | Tags: assembly, CeFO, design, manufacturing, testing
@misc{ROLLANDc,
title = {Applications and Challenges with Freeform Optics},
author = {Rolland, J. P.},
year = {2014},
date = {2014-06-22},
note = {Keynote speech at ASPE, (Hawaii, Big Island, 22-26 June 2014)},
keywords = {assembly, CeFO, design, manufacturing, testing},
pubstate = {published},
tppubtype = {presentation}
}
Echter, M. A.; Roll, C. D.; Keene, A. D.; Ellis, J. D.
Carrier fringe analysis algorithms for three degree of freedom optical probing Journal Article
In: Precision Engineering, vol. 34, no. 4, pp. 893-902, 2014.
Abstract | Links | BibTeX | Tags: CeFO, testing
@article{Echter14,
title = {Carrier fringe analysis algorithms for three degree of freedom optical probing},
author = {Echter, M. A. and C. D. Roll and A. D. Keene and J. D. Ellis},
doi = {http://dx.doi.org/10.1016/j.precisioneng.2014.05.005},
year = {2014},
date = {2014-05-19},
journal = {Precision Engineering},
volume = {34},
number = {4},
pages = {893-902},
abstract = {In this work, we present a fiber-delivered and fiber-detected, 3-DOF optical probe concept for measuring optical components to be used in conjunction with an optical coordinate measuring machine (OCMM). The optical probe uses a Michelson interferometer to produce carrier fringes and a high density fiber bundle to transmit interferograms that are recorded away from the probe head in a remote imaging system. We compare several different signal FFT processing techniques (parabolic interpolation, windowing, and zero padding) and a single-bin DFT technique to compute and enhance the resolution of the displacement, tip, and tilt of a moving mirror. We simulated varying signal-to-noise ratios and interference fringe contrast ranges to determine the algorithms’ sensitivity to those parameters and compare our simulated values to measured SNR and fringe values. Based on this work, it should be possible to use a carrier fringe algorithm for fiber probing applications if the interferogram can be transmitted through the fiber bundle with sufficient contrast (40%) and SNR (30 dB).},
keywords = {CeFO, testing},
pubstate = {published},
tppubtype = {article}
}
In this work, we present a fiber-delivered and fiber-detected, 3-DOF optical probe concept for measuring optical components to be used in conjunction with an optical coordinate measuring machine (OCMM). The optical probe uses a Michelson interferometer to produce carrier fringes and a high density fiber bundle to transmit interferograms that are recorded away from the probe head in a remote imaging system. We compare several different signal FFT processing techniques (parabolic interpolation, windowing, and zero padding) and a single-bin DFT technique to compute and enhance the resolution of the displacement, tip, and tilt of a moving mirror. We simulated varying signal-to-noise ratios and interference fringe contrast ranges to determine the algorithms’ sensitivity to those parameters and compare our simulated values to measured SNR and fringe values. Based on this work, it should be possible to use a carrier fringe algorithm for fiber probing applications if the interferogram can be transmitted through the fiber bundle with sufficient contrast (40%) and SNR (30 dB).