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Dual beam generation at a ray caustic by a multiplexing computer-generated hologram.
Optics Express
|June 6, 2009
Summary
Computer generated holograms (CGHs) can be placed at ray caustics to minimize their size. This innovation enables the certification of null correctors previously limited by CGH fabrication constraints.
Area of Science:
- Optics and Photonics
- Metrology
- Optical Engineering
Background:
- Computer generated holograms (CGHs) are crucial for testing aspherical surfaces and certifying null lens systems.
- Current fabrication limits for high-precision CGHs restrict the size and application of these essential metrology tools.
Purpose of the Study:
- To demonstrate a novel placement strategy for null-corrector-certifying CGHs to minimize their physical size.
- To enable the certification of null correctors that are currently uncertifiable due to CGH size limitations.
Main Methods:
- Investigated the placement of a CGH at a ray caustic within an optical system.
- Developed a proof-of-principle CGH with a diameter of approximately 20 mm and a fabrication tolerance of 1 part in 10^4.
Main Results:
- Demonstrated that locating a CGH at a ray caustic significantly minimizes its required size.
- Successfully created a compact CGH (20 mm diameter) suitable for certifying null correctors, overcoming previous size restrictions (200-250 mm).
Conclusions:
- Placing CGHs at ray caustics is an effective method to reduce their size, expanding their applicability in optical testing.
- This technique overcomes fabrication size limitations, making it possible to certify previously uncertifiable null correctors for aspheric mirror testing.
