Patent ID: 6947134

Claim:
An Aerosol Fluorescence Spectrum Analyzer comprising: an optical element which transfers light from a particle detection region in a first focal plane to a second focal plane; an aerodynamic flow system to move particles to and through the detection region; a first trigger laser emitting a beam of wavelength ë 1 and focused in a trigger region through which particles flow on their way to the detection region; a second trigger laser emitting a beam of wavelength ë 2 aimed in a direction approximately orthogonal to the direction of the first trigger laser and focused on the trigger region, the trigger region being defined by the intersection of the first and second trigger laser beams; a first wavelength-selective photodetector sensitive to light scattered from the trigger region and emitting an output signal in response to light of wavelength ë 1 ; a second wavelength-selective photodetector sensitive to light scattered from the trigger region and emitting an output signal in response to light of wavelength ë 2 ; a pulsed probe laser which emits a pulse of light having a predetermined diameter, centered on the particle detection volume triggered by the logically ANDed output signals of the first and second wavelength-selective photodetectors to emit a pulse of light substantially in the first focal plane and downstream of the particle detection volume; a spectral dispersing element positioned in the second focal plane; a photosensor optically connected to the spectral dispersing element, triggered by the logically ANDed outputs of the first and second wavelength-selective photodetectors; and a nozzle, coupled to aerodynamic flow system, said nozzle producing a focused aerosol jet having a diameter approximately matching the predetermined diameter of the pulsed probe laser such that the pulsed probe laser illuminates a region substantially the same size as the focused aerosol jet.