Localized Surface Plasmon Resonance Enhanced And Modulated Photoluminescence From Gold

Photoluminescence (PL) from metals has been attributed to the radiative recombination of conduction band electrons below the Fermi energy with d-band holes. Compared to the fluorescence of fluorescent molecular and semiconductor quantum dots, the PL of metals shown some unique characteristics such as non-bleaching, non-blinking and high-solution imagining, which shows a good prospect of the application in many fields, such as cell imaging, bio-sensing and plasmonic mode mapping. Meanwhile, metallic nanostructures could support Localized Surface Plasmon (LSP) which will greatly enhance the local field intensity in the near-field region of the nanostructures. Recently, it has drawn a lot of attentions on how to enhance and modulate the PL of metals based on localized plasmon resonances.In our thesis, we mainly discuss the enhancement and modulation of PLs from gold using LSPs supported by the nanostructures. The main contents of this thesis are as follows.First, we demonstrate the broad-band absorption in visible region of the multilayer metal-dielectric-metal (MIM) nanostructure via changing the parameters of the dielectric layer and the upper gold nanoparticle layer. Next, the characteristics of the PL signal of gold in this MIM nanostructure are discussed. We find that the PL intensity is positively correlated to the absorption efficiency in visible region of MIM nanostructure. In the perfect absorption condition, the intensity of the PL signal reaches the maximum, which is 9 times of the intensity of the PL from planar gold.Next, we study the characteristics of the PL from gold in a dielectric-metal core-shell resonator (DMCSR), which is composed of a dielectric core coated with a gold nanoshell layer. We observe a set of narrow-band PL peaks in the PL signal from gold nanoshells as well as an enhancement of the PL signal. Compared to the calculation results of Mie theory, we find that these narrow-band PL peaks are resulted from the coupling between the PL signal and a set of sharp cavity plasmons supported by the DMCSRs. Besides, we demonstrate that we can tune the positions of the PL peaks through changing the size of the dielectric cores, which provides an efficient method to shaping the PL of gold.