Plasmonic Field-Guided Patterning of Hybrid Nanostructured Gratings for Their Plasmon-Mediated Optical Activities

Combining the nano- and macroworlds in nanophotonics is always a great challenge for manufacturing uniform plasmonic nanogratings to achieve overall extraordinary optical properties. This work reports a method to apply large-area nanostructured gratings to tune the fluorescence behavior of quantum dots (QDs). The angle-resolved spectral measurements on the Ag NPs-based nanogratings show that the transverse electric (TE) polarized incident light has suffered very little scattering, demonstrating photon energy is coupled with plasmonic energy on the Ag NP-based lines. This plasmon-induced energy transferring effect was further used to tune the plasmon-induced QD fluorescence on the nanogratings. The QDs on Ag NP-based nanogratings, exhibiting up to 5 times higher photoluminescence (PL) intensity than that on a random Ag NP-based film, are carefully characterized using PL spectroscopy. In contrast, the bare QDs directly coupled onto the nanogratings. Spectral measurements in combination with numerical simulations demonstrate that anisotropic plasmon-induced energy transfer in the nanocomposite system plays a critical role in overall fluorescent tuning. Such nanogratings exhibit multifunctionality, offering an efficient way to fabricate plasmonic nanograting-QD composites with great potential applications in plasmonic sensors, QD displays, and fluorescent spectroscopy.