The spectral properties of the emission of a colloidal suspension of titanium dioxide particles in Rhodamine 640 perchlorate were studied systematically. The particle density <i>ρ</i>, the dye concentration <i>c</i>, and the energy of the pump pulse were varied over several orders of magnitude; the dependence of the spectra on these three parameters is discussed. We discovered a strong correlation between the particle density and the dye concentration. The amplification by stimulated emission was found to be strongest when the absorption length <i>l</i><sub>a</sub> and the mean-free-path length <i>l</i><sup>*</sup> had approximately the same magnitude. The respective <i>l</i><sup>*</sup> values were determined by a pulsed transmission experiment.
© 1997 Optical Society of America
G. Beckering, S. J. Zilker, and D. Haarer, "Spectral measurements of the emission from highly scattering gain media," Opt. Lett. 22, 1427-1429 (1997)