Nonspatial Filterinfg for Laser Beams

Period of Performance: 01/01/1994 - 12/31/1994


Phase 1 STTR

Recipient Firm

Northeast Photosciences, Inc.
18 Flagg Road
Hollis, NH 03049
Principal Investigator

Research Institution

Massachusetts Institute of Technology
77 Massachusetts ave
Cambridge, MA 02139
Institution POC


We propose a laser beam cleanup, the nonspatial filter, which is based on the Bragg selectivity of thick holograms. Unlike pinhole and fiber spatial filters, which employ lenses and apertures in the transform plane, nonspatial filters operate directly on the laser beam angle. This eliminates the need for laser beam focusing, which is the source of many of the alignment instabilities and laser power limitations of spatial filters. Standard holographic materials are not suitable for this application because differential shrinkage during processing limits the maximum Bragg angle selectivity attainable. Instead, we propose to fabricate our own material using two commercially available photopolymers. One will be pre-exposed to create a porous but rigid host structure for the other, which will be used to write the actual filter hologram.