Droplet lasing spectroscopy has been applied to the measurement of droplet size and evaporation rate in a spray. A single droplet, doped with laser dye, was injected along the centerline of a liquid spray. Filters were used to block the strong elastic-scattering signal. The lasing emission from the doped droplet could be detected against the background with mass loadings of liquid in the spray as high as 20%. An analysis of the spectrum of droplet lasing was used to evaluate the droplet diameter. The evaporation rate of the droplet was obtained from consecutive lasing spectra that were obtained from the same droplet. An error analysis of the drop size and drop evaporation measurements was carried out and showed that accurate measurements of evaporation rates were feasible.
© 1998 Optical Society of America
(010.1110) Atmospheric and oceanic optics : Aerosols
(120.1740) Instrumentation, measurement, and metrology : Combustion diagnostics
(300.2530) Spectroscopy : Fluorescence, laser-induced
(300.6170) Spectroscopy : Spectra
Philip J. Santangelo, Daniel Flowers, and Ian M. Kennedy, "Demonstration of Droplet Size and Vaporization Rate Measurements in the Near Field of a Two-Phase Jet with Droplet Lasing Spectroscopy," Appl. Opt. 37, 5573-5578 (1998)