Article ID Journal Published Year Pages File Type
1496438 Optical Materials 2008 6 Pages PDF
Abstract

Recently developed deep-ultraviolet light-emitting diodes (UV LEDs) emit at wavelengths short enough to excitate fluorescence in most biological autofluorophores. We demonstrate the possibility of harmonical modulation of the output of group-III-nitride based UV LEDs ranging from 255 to 375 nm at frequencies up to 200 MHz. This enables the application of UV LEDs for frequency-domain fluorescence lifetime sensing with subnanosecond resolution. We report on measurements of fluorescence decay time in common biofluorophores (tyrosine, tryptophan, NADPH, NADH, collagen, DPA, elastin and riboflavin) using commercially available UV LEDs. We demonstrate the capacity of a multichannel LED-based frequency-resolved measurement technique to discriminate between Bacillus globigii and a variety of ambient interferants such as diesel fuel, paper, cotton, dust, etc.

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Physical Sciences and Engineering Materials Science Ceramics and Composites
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