Very large computer generated holograms for precision metrology of aspheric optical surfaces

Award Information
Agency: National Aeronautics and Space Administration
Branch: N/A
Contract: NNX12CF50P
Agency Tracking Number: 114909
Amount: $124,957.00
Phase: Phase I
Program: SBIR
Awards Year: 2012
Solicitation Year: 2011
Solicitation Topic Code: S2.05
Solicitation Number: N/A
Small Business Information
8943 North Veridian Drive, Tucson, AZ, 85743-9087
DUNS: 961529919
HUBZone Owned: N
Woman Owned: N
Socially and Economically Disadvantaged: N
Principal Investigator
 Chunyu Zhao
 Principal Investigator
 (520) 248-4453
Business Contact
 Chunyu Zhao
Title: Business Official
Phone: (520) 248-4453
Research Institution
Both ground and space telescopes employ aspheric mirrors. A particular example is the X-ray telescope where primary and secondary mirrors have nearly cylindrical surfaces. Computer Generated Holograms (CGH), in combination with commercial interferometers, provide high resolution and high accuracy measurements of aspheric optical surfaces. The current state of the art CGHs are made on 6" square substrates such as those for testing the primary segments of James Webb Space Telescope. However, larger CGHs are always desired. A larger CGH enables testing of correspondingly larger convex and nearly cylindrical concave surfaces in one shot; studies have shown that larger CGHs also offer better imaging of the surface under test, which improves the CGH null test system's Instrument Transfer Function, an equivalent metric to an imaging system's Modulation Transfer Function. Furthermore, pursuit of improving CGH test accuracy never ends. The fundamental limiting factor is quality of the substrate. The current state of the art technology is still unable to fabricate general CGHs of arbitrary symmetry on high quality custom substrates.Arizona Optical Metrology LLC (AOM) proposes to address these problems. We propose to work with our collaborators at the ebeam facility of Jet Propulsion Laboratory of NASA to write large CGHs on high quality substrates. We anticipate the writing has reasonable yet non-negligible errors which cause errors in the aspheric wavefront the CGH produces. The wavefront error must be calibrated in order to meet the demanding accuracy requirement of precision aspheric surface metrology. We propose to develop a technology that enables accurate calibration of the writing error, such that the CGH still measures an aspheric surface to an excellent accuracy of a couple of nm rms. The goal of phase 1 is to develop the software tools for calibrating the CGH writing error, and fabricate a couple of 9 inch diameter CGHs to experimentally validate the technology.

* Information listed above is at the time of submission. *

Agency Micro-sites

SBA logo
Department of Agriculture logo
Department of Commerce logo
Department of Defense logo
Department of Education logo
Department of Energy logo
Department of Health and Human Services logo
Department of Homeland Security logo
Department of Transportation logo
Environmental Protection Agency logo
National Aeronautics and Space Administration logo
National Science Foundation logo
US Flag An Official Website of the United States Government