Degradation of Rhodamine B Through Plasmon-Assisted R.O.S Generation of Gold Nanorods

Plasmonically enhanced femtosecond irradiation was found to exhibit a remarkable selective inactivation of pathogens while exhibiting minimal side effects on representative biologic and mammalian cell targets. Within the rich set of femtosecond light-matter interactions, nanocavitation was found to be the primary method of inactivation. Under comparable conditions, we report R.O.S mediated degradation of Rhodamine B in the presence of gold nanorods with longitudinal surface plasmon resonance (LSPR) of 750-760nm irradiated by 800nm 100-fs Ti-Sapphire regeneratively amplified laser pulses up to 3mJ/cm². Rhodamine B is a known carcinogenic waste-water pollutant that cannot be degraded easily by current waste-water treatment technologies. We also utilize it as a reporter of generated R.O.S, through a robust and accessible fluorescence monitoring scheme to track kinetics of Rhodamine B degradation. We elucidate the dependence of R.O.S generation on nanorod volume, presence of ligands, and pump fluences. Alongside ongoing theoretical and experimental studies on plasma and R.O.S generation through ultrafast irradiation of gold nanorods, it is interesting to explore R.O.S generation for therapeutic and chemical applications, and better theoretical understanding of the ultra-fast high power light-matter interactions.