KINAM JUNG, Jungsuk Hahn, Sungjun In, Heechul Lee, Peter Pikhitsa, Kwangjun Ahn, Kyungyun Ha, Junhoi Kim, Jongkwon Lee, Sunghoon Kwon, Namkyoo Park, Mansoo Choi, Seoul National University
Abstract Number: 157 Working Group: Nanoparticles and Materials Synthesis
Abstract We fabricate four different arrays of 3D plasmonic multipetal flower (m-PF) assemblies composed of nanoparticles for SERS substrates using spark discharge and ion induced electrostatic focusing method. We demonstrate the control of SP hot-spots as a function of the petal number m (4, 6, and 8). With the increase of the petal number, both the numbers of hot-spots that are formed in 3D nanogaps located between adjacent petals, and the field intensity in the hot-spots show m-proportional increase, to consequently result in approximately m^2 dependencies in the SERS enhancement as a whole. The obtained SERS enhancement is 10^6 ~ 10^7, sufficient for the single molecule detection. Quantitative and qualitative optical behaviors of fabricated 3D multipetal flower assemblies are also studied by measuring dark field (DF) spectra. Enhanced excitation of non-radiative higher order SP modes for the higher m-petal flowers is also interpreted in terms of m-petal geometry, in agreement with the results of SERS, DF spectra, and rigorously calculated near field distributions.