Rajagopal: Unraveling Plasmon-Enhanced Reactive Oxygen Species Generation through Ultrafast Light

The interaction of ultrafast light with AuNRs has a rich non-linear phase space which can result in the production of nanobubbles, shockwaves, plasma, associated reactive oxygen species (ROS), and the reshaping and melting of the nanorods. These high energy processes have found practical applications for cell nanosurgery, the destruction of cancer cells, and inactivation of microbes. To optimize nanorod-enhanced ultrafast laser technologies for translational applications, it is critical to disentangle the impact of photothermal, cavitation, plasma, and ROS effects on pathogens and cells, especially considering the typically high irradiances up to several TW/cm2 applied in these experiments. We characterize Reactive oxygen species (ROS) generation through gold nanorods (AuNRs) excited by 812 nm centered, 85 femtosecond (fs)-pulsed laser irradiation through a rhodamine B degradation assay for fluences up to 5 mJ/cm2. We study the impact of fluence, AuNR size, and AuNR surface capping on ROS generation