| NSF Org: |
AST Division Of Astronomical Sciences |
| Recipient: |
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| Initial Amendment Date: | May 19, 2011 |
| Latest Amendment Date: | August 7, 2013 |
| Award Number: | 1105615 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Ralph Gaume
AST Division Of Astronomical Sciences MPS Directorate for Mathematical and Physical Sciences |
| Start Date: | July 1, 2011 |
| End Date: | June 30, 2015 (Estimated) |
| Total Intended Award Amount: | $899,151.00 |
| Total Awarded Amount to Date: | $899,151.00 |
| Funds Obligated to Date: |
FY 2012 = $360,180.00 FY 2013 = $115,805.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
1 SILBER WAY BOSTON MA US 02215-1703 (617)353-4365 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
1 SILBER WAY BOSTON MA US 02215-1703 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | ADVANCED TECHNOLOGIES & INSTRM |
| Primary Program Source: |
01001213DB NSF RESEARCH & RELATED ACTIVIT 01001314DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.049 |
ABSTRACT
Over the past decade, adaptive optics (AO) has become indispensible as a means to compensate for aberrations introduced by atmospheric turbulence in large ground-based telescopes. The resulting gains in resolution are especially important for large telescopes. Indeed, because of their greater aperture, large ground-based telescopes have exceeded in narrow fields the fidelity possible with orbiting observatories and have led to exciting recent advances in the observation of exoplanets, characterization of planetary rings and atmospheres, and studies of galactic structure. The universal optical component that allows for this wavefront compensation is a deformable mirror (DM), which must operate at frequencies above 1 kHz and whose actuator count scales with the area of the telescope primary mirror. Indeed, DMs with tens of thousands of actuators are required for planned extremely large telescopes (ELTs) - those with apertures greater than ~20-m.
The technology to make high-actuator density DMs with high production yield and therefore low cost does not exist today. A main objective of work planned by Dr. T. Bifano of Boston University is to develop such manufacturing technologies using a microelectromechanical systems (MEMS) approach. A critical failure mode of current large-format DMs has been the thousands of fragile electrical traces that route signals along the front surface from bonding pads located near the periphery of the module. This problem worsens rapidly as the actuator count increases, culminating in a yield of less than 1% for the latest attempts at constructing a high-count DM for the Gemini Planet Imager (GPI). Dr. Bifano's plans to circumvent this problem involve replacing the dense network of surface traces with through-wafer interconnects and bonding to a backside package. While this basic technique is not unprecedented in modern electronics manufacturing, technical challenges include the very large voltages (~250V) that must be endured by the silicon substrate to achieve the required DM stroke of ~3.5 microns. However, the payoff is large, since the availability of reliable high-actuator-count DMs would catalyze advances in promising imaging techniques such as Multi-Object AO and Extreme AO. An outcome of the proposed project will be fully functional MEMS DM prototypes with 2048 actuators, evaluated at a leading astronomical AO test bed. Funding for development high actuator count DMs for next-generation AO is being provided by NSF's Division of Astronomical Sciences through its Advanced Technologies and Instrumentation program.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
In the proposed project we produced and evaluated a new type of scalable, cost-effective, high-spatial-resolution deformable mirror (DM) for astronomical adaptive optics (AO). Over the past decade, AO has become indispensible as a means to compensate aberrations introduced by atmospheric turbulence in large ground-based telescopes. Affordable DMs with thousands of actuators will be immediately useful in existing telescopes, and devices with tens of thousands of actuators are needed for planned extremely large telescopes ELTs.
A main objective of this work was to develop such manufacturing technology using a microelectromechanical systems (MEMS) approach. The project addressed a major limitation encountered in prior high-actuator-count MEMS DM development: low yield due to defects in the device’s wire-routing layer. A key process science innovation that was explored in this program is through-wafer-via interconnection. By vertically routing actuator connections through the wafer instead of fanning out dense, failure-prone thin-film wire-routing lines to peripheral bond pads on the top surface of the wafer, the approach substantially improved device yield. It also provided a technological foundation for producing DMs with even higher spatial resolution, in support of AO for ELTs and planet-finding instruments.
A graduate student was trained and mentored in design, manufacture, and testing of MEMS DMs for astronomical AO. In addition, three undergraduate interns and four STEM teachers serving underrepresented minority populations were supported in work associated with this project.
Last Modified: 10/29/2015
Modified by: Thomas G Bifano
