Resources
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CAD Models
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- CAD Model: CGH-S9-C9_A.step
- CAD Model: CGH-S9-C0_A.step
- CAD Model: CGH-S6-C6_A.step
- CAD Model: CGH-S6-C0_A.step
- CAD Model: CGH-S3-C6_A.step
- CAD Model: CGH-S3-C3_A.step
- CAD Model: CGH-S3-C0_A.step
- CAD Model: C6XXXC_A.step
- CAD Model: C4XXXC_A.step
- CAD Model: C3XXXs_A.step
- CAD Model: C2XXXS-BC.step 2-Inch Cylinder CGH
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Documentation
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- Customer Drawing: MP6-BLANK_A
- Customer Drawing: MP3-BLANK_A
- Customer Drawing: VRT-050_A
- Customer Drawing: CRT-050_A
- Customer Drawing: C6AC3_A
- Customer Drawing: C6R_A
- Customer Drawing: FP9-H600_A
- Customer Drawing: FP6-H600_B
- Customer Drawing: FP6-H425_B
- Customer Drawing: FP3-Z-H600_B
- Customer Drawing: FP3-Z-H425_B
- Customer Drawing: FP3-H600_A
- Customer Drawing: FP3-H425_A
- Customer Drawing: CGH-S9-C9_A
- Customer Drawing: CGH-S9-C0_A
- Customer Drawing: CGH-S6-C6_A
- Customer Drawing: CGH-S6-C0_A
- Customer Drawing: CGH-S3-C6_A
- Customer Drawing: CGH-S3-C3_A
- Customer Drawing: CGH-S3-C0_A
- Customer Drawing: C6XXXC_A
- Customer Drawing: C4XXXC_A
- Customer Drawing: C3XXXS_A
- Customer Drawing: C2XXXS-BC 2-Inch Cylinder CGH
- Customer Drawing: FP6-Z-H650_A
- Show Remaining Articles ( 10 ) Collapse Articles
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Publications
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- [2023] New Applications of Computer Generated Holograms for Optical Testing
- [2023] Rapid surface metrology of freeform shapes using CGH interferometry
- [2022] Snapshot measurements with CGH interferometry to support volume production of freeform optics
- [2022] Computer generated hologram (CGH) education kit for hands-on learning of optical metrology for complex optics and systems
- [2022] CGH-assisted metrology testbed for the Thirty Meter Telescope primary mirror
- [2021] Metrology Testbed for the Thirty Meter Telescope Primary Mirror
- [2019] Interferometric Metrology for the TMT Primary Mirror Segments: Design and Analysis
- [2018] Infrared computer-generated holograms: design and application for the WFIRST grism using wavelength-tuning interferometry
- [2016] Optical Alignment with CGH Phase References
- [2014] Precision Alignment And Calibration Of Optical Systems Using Computer Generated Holograms
- [2014] Diffractive optics calibrator: measurement of etching variations for binary computer-generated holograms
- [2013] Optical testing with computer generated holograms: comprehensive error analysis
- [2013] Design and analysis of an alignment procedure using computer-generated holograms
- [2011] Low uncertainty alignment procedure using computer generated holograms
- [2010] Imaging issues for interferometry with CGH null correctors
- [2010] Measurement of aspheric mirror segments using Fizeau interferometry with CGH correction
- [2009] Fizeau interferometer with spherical reference and CGH correction for measuring large convex aspheres
- [2007] Fabrication error analysis and experimental demonstration for computer-generated holograms
- [2007] Optical alignment with computer-generated holograms
- [2007] Optimal design of computer-generated holograms to minimize sensitivity to fabrication errors
- [2007] Coupling of surface roughness to the performance of computer-generated holograms
- [2006] Analysis of phase sensitivity for binary computer-generated holograms
- [2006] Absolute calibration of null correctors using twin computer-generated holograms
- [2006] Use of computer generated holograms for alignment of complex null correctors
- [2005] Testing an off-axis parabola with a CGH and a spherical mirror as null lens
- [2004] Efficient testing of segmented aspherical mirrors by use of reference plate and computer-generated holograms. I. Theory and system optimization
- [2004] Efficient testing of segmented aspherical mirrors by use of a reference plate and computer-generated holograms. II. Case study, error analysis, and experimental validation
- [1999] Efficient testing of off-axis aspheres with test plates and computer-generated holograms
- [1999] Error analysis for CGH optical testing
- [1999] Diffraction wavefront analysis of computer-generated holograms
- [1995] Applications of computer-generated holograms for interferometric measurement of large aspheric optics
- Show Remaining Articles ( 16 ) Collapse Articles
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FAQs
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- What is a CGH?
- How are CGHs used?
- What is a "null"?
- What is a "UUT"?
- How is a CGH mounted and adjusted?
- What types of surfaces can be measured using a CGH?
- What is the typical accuracy of a CGH?
- What are the benefits of using a CGH for metrology?
- What is CGH substrate error and how does it get subtracted?
- What are fiducial dots and how are they used?
- Are CGHs delicate?
- How do you clean a CGH?
- What is a Metrology Platform?
- What type of interferometer do I need to use a CGH?
- What is diffraction efficiency?
- What is the difference between an amplitude and a phase CGH?
- How is a CGH different from other types of holograms?
- What size CGHs does AOM produce?
- Do CGHs require regular calibration?
- Show Remaining Articles ( 4 ) Collapse Articles
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How-To's
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Technologies
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- Arc Focus Reference Alignment Patterns (AF)
- Crosshair Point Focus (PF-X)
- Line Focus Reference Alignment Patterns (LF)
- Confocal Point Focus Alignment Pattern (PF-C)
- Catseye Pair Alignment Pattern (CE-P)
- Catseye Single Alignment Pattern (CE-S)
- Collimation Alignment Pattern (CO)
- Visual Point Focus Alignment Pattern (PF-V)
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Name & ID | Symbol | Typical Target Used | DOF and Sensitivity | Description |
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Crosshair Point Focus (PF-X) | Reflective Tooling Ball | Mid-range dX and dY Fine dZ | Projects a focused spot to vertex of a reflective tooling ball. These patterns also utilize a crosshair to provide visual lateral alignment feedback. |
Crosshair point focus PF-X alignment patterns work by bringing light to focus on the surface of a (generally) curved alignment target, such as a reflective tooling ball.
Decenter misalignment of a PF-X pattern leads to displacement of the return beam in that direction.
To aid in aligning the displaced beam, AOM adds an opaque crosshair mark on top of the focusing pattern.
The video below shows the lateral alignment process of a PF-X pattern as viewed by an interferometer.
Spacing (Z) misalignment shows up in PF-X patterns as power fringes.
Click here for a summary table of all AOM alignment patterns.
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