Figure 2: Threshold behaviour of random Raman lasing.
(a) Output Raman pulse energy versus incident pump pulse energy indicating a clear threshold where random Raman lasing begins. Black circles are the experimental data points, dashed blue line is a linear fit of the last four experimental data points and green triangles are the results of Monte Carlo simulations. (b) SRS spectra of BaSO4 powder at various pump powers illustrating the presence of higher-order Raman transitions. The spontaneous Raman spectrum of BaSO4 is shown for comparison, but was taken with a much higher resolution spectrometer. All spectra have been normalized to fit on the same scale, and the widths of the SRS spectral peaks were limited by the resolution of the spectrometer used. a.u., arbitrary unit.
