Random lasing assisted by CuSO_4 and Au nanoparticles in random gain systems

Abstract

Random laser actions from a dye pyrromethene-597(PM597)-doped CuSO4 mixture infiltrated in glass capillaries are demonstrated. Discrete lasing modes are observed at the complete solid angle. Low threshold and variable emission wavelength of the random lasers are realized by adjusting the concentration of CuSO4 in the mixtures. With the exception of the multiple scattering of light caused by micro-crystals dispersed in the mixtures, another underlying physical mechanism for tuning random laser is closely related to energy transfer between the molecules of PM597 and CuSO4. Meanwhile, we also demonstrate the realization of a plasmonic random laser by doping Au nanoparticles (NPS) in the PM597-doped CuSO4 mixture. We find that the localized surface plasmon resonance of Au NPS lowers the threshold, increases the emission intensity and reduces the number of the lasing modes of the random lasers. Our results indicate that CuSO4 paves a new avenue towards designing low-cost photonic devices based on the random lasers.