Development of a Stretchable Concave Imaging Membrane Mirror of Variable Focus
Abstract
The report describes the evolution of a plastic membrane, variable focus, concave imaging mirror, a 'zoom' mirror. A partial vacuum behind the membrane is used to create a uniform pressure difference across the membrane and force it back into a concave shape. Range of curvatures (obtainable) is from the flat to F/0.5, the classical limit for imaging in concave mirrors. Plastic membranes have been metallized with surface roughnesses down to 10 angstroms, as good as any mirror polished to date. Shearing interferometry has been used to study mirror symmetry. Frames are being evolved to support the membrane in such a way that the mirrors will be interferometrically symmetrical and capable of excellent imaging. Plastic membranes can be obtained to 17 meters wide, enabling mirrors to around 50 feet in diameter to be built and capable of optical imaging. A space mirror has been built, capable of operation even in a total vacuum. The mirrors are vacuum sealed and can retain any one curvature for long periods of time. The mirrors have been used with gas lasers to create very large sized holograms and white light holograms. Great Britain.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 20, 1988
- Accession Number
- ADA197228
Entities
People
- P. Waddell
Organizations
- University of Strathclyde