Stimulated Raman Scattering of Aqueous Droplets Containing Ions: Concentrationand Size Determination

摘要

The dependence of the detected Raman scattering intensity as the input laserintensity is increased can be separated into four regions: (1) spontaneous Raman scattering at low input intensity; (2) stimulated Raman scattering (SRS) with an exponential growth; (3) saturated SRS; and (4) laser-induced breakdown (LIB) within the droplet at high input intensity. Within the exponential growth region, the relative SRS intensity can be related to the relative concentration of the ions. At high nitrate and sulfate ion concentrations, the series of SRS peaks centered around the v1 vibrational mode of the ions provide information on the droplet size.