NASA SBIR 2004 Solicitation


PROPOSAL NUMBER: 04 S3.02-9660
SUBTOPIC TITLE: High Contrast Astrophysical Imaging
PROPOSAL TITLE: High Resolution Silicon Deformable Mirrors

SMALL BUSINESS CONCERN (Name, E-mail, Mail Address, City/State/Zip, Phone)
Boston Micromachines Corp
108 Water Street
Watertown, MA 02472-4696

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Paul Bierden
108 Water Street
Watertown, MA 02472-4696

This proposal describes a plan to build a prototype small stroke, high precision deformable mirror suitable for space-based operation in systems for high-resolution imaging. The prototype DM will be fabricated through a novel combination of micromachining and wafer bonding steps, and will rely on single crystal silicon for all structural components, promising unprecedented thermal stability and optical quality. These DMs will have a 65 mm aperture diameter, 4096 of degrees of freedom, 1?m of stroke, and a highly reflective mirror surface that can be adjusted repeatably to within 1nm RMS over the controllable range of spatial frequencies. The device will address all fundamental requirements for DMs to be used in space-based applications, by combining the best features of conventional discretely-assembled macroscale DMs (e.g. large aperture, good optical quality, and high reliability) with the best features of integrated microelectromechanical system (MEMS) DMs fabricated using semiconductor processing techniques (e.g. nanometer-scale repeatability, scalability to >104 actuators, and compactness). By using the full area of a silicon wafer for each mirror, these MEMS DMs will be significantly larger than any previously-reported MEMS DM. The device architecture will parallel that of the highly successful commercial MEMS DMs that were pioneered by Boston Micromachines Corporation.

The proposed research activities would support all of NASA's planned large aperture missions. In these missions the inherent figure errors and compliance of lightweight primary mirrors will reduce the system's passive performance. It is expected that larger, lighter weight systems will require adaptive systems to achieve acceptable optical performance. Active and adaptive systems will be used to measure and correct wavefront errors for large aperture telescopes and control dynamic changes in the optical structure. Lightweight, low-power deformable mirror technology such as that described in this proposal will be required for several SSE and ESE roadmap missions requiring optical large apertures.

The devices that are proposed in this program could be used for any application where dynamic wavefront correction would be required and the current technology (macro-scale DM or liquid crystal SLMs) is limited, either by cost, size, speed, or optical characteristics. Examples of such applications are inter-cavity laser correction, laser welding, long range laser communication and biomedical imaging. Each of these applications, if successfully demonstrated, would lead to a large commercial market for the proposed silicon deformable mirrors.