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Single-shot fluorescence spectra of individual micrometer-sized bioaerosols illuminated by a 351- or a 266-nm ultraviolet laser

1999; Optica Publishing Group; Volume: 24; Issue: 2 Linguagem: Inglês

10.1364/ol.24.000116

1539-4794

Yong‐Le Pan, Stephen Holler, Richard K. Chang, Steven C. Hill, Ronald G. Pinnick, Stanley Niles, Jerold R. Bottiger,

Spectroscopy and Laser Applications

Reproducible fluorescence spectra of individual 2- to 5??m-diameter biological aerosol particles excited with a single shot from a Q-switched laser (266 or 351??nm) have been obtained with highly improved signal-to-noise ratios. Critical to the advance are crossed diode-laser trigger beams, which precisely define the sample volume, and a reflecting objective, which minimizes chromatic aberration and has a large N.A.??for collecting fluorescence. Several allergens (red oak, meadow oat pollen, paper mulberry pollen, and puffball spores) have different fluorescence spectra. Bacillus subtilis fluorescence spectrum deteriorates at high 266-nm incident intensity. Dry riboflavin particles illuminated with a 351-nm light exhibit a new 420-nm fluorescence peak that grows nonlinearly with laser pulse energy.