Random Lasing and Stimulated Raman Scattering in Highly Porous Nanostructured Aluminum Oxyhydroxide Monoliths with Rhodamine 6G

We report an investigation of random lasing, which occurs together with stimulated Raman scattering (SRS), under picosecond pumping of 3D nanostructures consisting of aluminum oxyhydroxide nanofibrils activated with Rhodamine 6G. Stimulated Raman scattering is excited by biharmonic pump, namely, Nd:YAG laser radiation and random lasing radiation generated in the system. As a result, SRS lines falling within the spectral region of random lasing generation provide information about the vibrational structure of laser dyes. It is demonstrated that the thresholds for the SRS and incoherent random lasing decrease as the laser spot area on the sample increases. It is shown that duration and rise time of the scattered signal are reduced, when the system is pumped with radiation with an energy higher than the random lasing excitation threshold. Given the potential for controlling the morphology of structures based on porous aluminum oxyhydroxide monoliths (PAOMs) over wide limits, using such systems as random lasing sources opens up extensive opportunities for controlling the spectral, energy, and temporal parameters of radiation over wide ranges.