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Interference filter refinement for artificial nose fluorescence sensing

2001; SPIE; Volume: 40; Issue: 6 Linguagem: Inglês

10.1117/1.1367255

1560-2303

Jeevananda Karunamuni, Katherine Stitzer, DeLyle Eastwood, Keith J. Albert, David R. Walt, Steven Brown, Michael L. Myrick,

Analytical Chemistry and Sensors

Optical interference coatings are used in filter-based T-format fluorimeters to make beamsplitters, bandpasses, and bandblocking filters that separate excitation and emission signals. Commercially available filters usually perform well in these applications, but better performance may be possible if the system of optical filters is tailored to the specific analysis. We provide a general method for designing optical filters for the optical train of a specific fluorescence sensor system simultaneously using two light-emitting diode (LED) excitation sources (blue and green) and two different fluorescent indicators. We approach the problem of designing the optics of the system by first constructing a hypothetical target spectrum for each filter using the optical spectrum of the excitation source, and the excitation and emission spectra of the fluorescence sensors. Structural designs for Nb2O5/SiO2 multilayer interference filters are then synthesized. An iterative evaluation procedure is then used to improve the performance of the system for minimal leakage of the excitation sources onto our detector array. We also provide experimental results for the construction of these filters using reactive magnetron sputtering.