Tuning Multi-wavelength Lasing in Rhodamine 640/Methylene Blue/Ag NWs Random Lasers

This research investigates a type of random laser with coherent properties, designed and studied to understand how fluorescence resonance energy transfer affects the emission spectra and threshold of Rhodamine 640/methylene blue/Ag NWs lasers. We demonstrate that Rhodamine 640 enhances the laser output of methylene blue beyond 700 nm. Additionally, by adjusting the mixing ratio of the two dyes, we achieved multi-wavelength lasing with linewidths as narrow as 1 nm. Ag NWs serve as scatterers in this system, both enhancing light extraction efficiency in the visible range and lowering the operating threshold for multi-wavelength lasing.