Infrared Bandpass Filters

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.