Temperature, Trace Species, and Phase Conjugation in Droplets and Sprays
Final rept. 15 Jul 94-14 Jul 94
YALE UNIV NEW HAVEN CT DEPT OF APPLIED PHYSICS
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Liquid microdroplets play an important role in combustion as well as atmospheric chemistry. Characterizing droplets in terms of size, shape, chemical composition, temperature, etc., is essential for research in these two fields. Nonlinear optics has proven to be a useful diagnostic tool for determining these important characteristics. The research funded by this contract has resulted in the development of three new diagnostic techniques for characterizing microdroplets with mode locked laser pulses 1 The temporal beating of adjacent, degeneracy split droplet cavity modes has been used to determine both the droplet distortion amplitude and the linewidths of the cavity resonances. 2 The localized, laser induced electrostrictive distortion induced by a train of mode locked laser pulses was shown to increase the input coupling to droplet cavity resonances for subsequent laser pulses and reduce the threshold for stimulated Raman scattering by almost two orders of magnitude. 3 Optical second harmonic generation has been used to both detect surfactant molecules adsorbed on droplet surfaces, as well as to determine the relative concentrations and molecular orientations of the surfactants.
- Lasers and Masers
- Fluid Mechanics