Harald Giessen

2021

1. Ai, Q., Zhang, H., Wang, J., & Giessen, H. (2021). Multiphoton Photoluminescence in Hybrid Plasmon–Fiber Cavities with Au and Au@Pd Nanobipyramids: Two-Photon versus Four-Photon Processes and Rapid Quenching. ACS Photonics, 8(7), Article 7. https://doi.org/10.1021/acsphotonics.1c00470
   • Abstract
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   Abstract

   We investigate the multiphoton photoluminescence (MPPL) characteristics of bare and palladium-capped gold nanobipyramid particles deposited on microfibers with diameters around 1.7 μm. A broad luminescence emission with two evident peaks is detected when the coupled gold nanobipyramid particles are illuminated with a femtosecond laser. By employing multiple peak Lorentz fitting to each PL emission spectrum and performing nonlinear order analysis of the excitation power-dependent measurement, we come to the conclusion that four-photon photoluminescence (4PPL) at around 520 nm and two-photon photoluminescence (2PPL) at longer wavelengths are the main constituents of the broad luminescence emission. Additionally, we observed unexpectedly that those two emission processes have different polarization characteristics. These characteristics can be understood and explained by taking into account the band and crystalline structure of the gold nanobipyramids. Furthermore, the L-band-related 4PPL emission is quenched for Au@Pd nanobipyramids due to the fast transfer of electrons from the gold to the palladium. This provides us with a new way of modifying the photoluminescence in coupled hybrid bimetallic nanostructures. This deeper understanding of MPPL in gold nanoparticles paves the way to precise control of the luminescence emission from plasmonic nanoparticles, which is crucial for further applications in biological imaging and photothermal therapy.

   Link

   /brokenurl# https://doi.org/10.1021/acsphotonics.1c00470