Figure 4.

(a) Spontaneous Raman spectrum of R6G with excitation wavelength of 532 nm. Adapted from Ref. [141] with permission from IOP Publishing. (b) Stimulated Raman scattering signals generated from an RL medium consisting of ZnO nanospheres and R6G methanol colloid in flask, pumped by a laser with wavelength of 532 nm, pulse duration of 7 ns and pump spot of 3 mm. Adapted from Ref. [140] with permission from Elsevier.