Improving diode laser induced fluorescence detection of airborne biological particles by exciting multiple biofluorophores

摘要

`Laser-induced fluorescence provides a real-time technique for detecting airborne pathogens. Discrimination between biological and non-biological particles can be improved by simultaneously testing for more than one of the several common biofluorophores. Typically, this requires excitation with two or more laser wavelengths, considerably increasing the cost, size and complexity of sensors based on mainframe lasers. Recent advances in UV-emitting AlGaN diode lasers present an opportunity for compact and inexpensive multi-wavelength excitation. In this paper, we will present a model for choosing the best excitation wavelengths and emission bands for discriminating between biological and non-biological particles. We will discuss recent advances in detection, and present fluorescence photon counting experimental results. We will describe techniques for simultaneous excitation and detection at multiple wavelengths to improve selectivity and guard against false positives.