ABSORPTION EFFECTS ON MICRODROPLET RESONANT EMISSION STRUCTURE

The effect of absorption on microdroplet resonance emission line intensities was studied in 15-mu-m-diameter Rhodamine 6G/ethanol solution droplets. Absorption was controlled by varying the concentration of the additive nigrosin. Spectrally integrated intensities of resonant features are found to be proportional to a droplet cavity mode efficiency Q(a)/(Q(a) + Q(o)) expressed in terms of cavity output coupling and absorption factors Q(o) and Q(a), respectively. These Q's are determined from linewidths calculated from Lorenz-Mie theory by using combinations of the real and complex indices of refraction. An experimental upper limit of Q for first-order modes was determined to be 10(8) from the data.