SBIR-STTR Award

This proposal is concerned with the design and fabrication of high performance infrared bandpass filters. These are optical filters that use multilayer coatings to produce high levels of blocking in certain spectral zones and high levels of transmission in other bands. Proposed is a methodology for the design of such filters using computer optimization of layer thickness values. Issues such as edge steepness and spectral shifts with angle of incidence are also addressed. A modeling effort is proposed which identifies the potential causes of degradation of fabricated filters. Included in this model will be chamber geometry, monitoring, and deposition processes. Well-defined deposition experiments will anchor the models to reality. Finally, a high performance infrared bandpass filter will be fabricated and its spectral transmission will be compared with that predicted by the design

High performance infrared bandpass filters will be produced through enhanced technology including, improved spectral measurement devices of filters and calibration samples, improved software for extracting optical constants from deposited thin films, improved deposition thickness monitoring devices, and computer integration of the deposition process. This proposed work will submit coatings on substrates with specially designed antireflection coatings on the back sides which demonstrate the capability of producing high performance infrared bandpass filters. Multiple samples will be delivered out of separate deposition runs to demonstrate process repeatability. Spectra resolution measurements will be made on all filters as well as some environmental durability tests.

Keywords:
Infrared Filters, Optical Coatings, Bandpass Filte