A metallic nanocavity can squeeze the visible light into highly confined intensive plasmon with a broad energy distribution. Such a unique excitation source can lead to many exciting new applications. One of the representative applications is the well-established surface enhanced Raman spectroscopy (SERS) that takes advantage of the high intensity of the plasmon to achieve effective detection of a very small numbers of molecules. I will present here our several new exciting findings from the use of NCP. Our combined theoretical and experimental studies reveal that the NCP acts like a tunable, strong and ultra-fast electromagnetic source that can naturally alter the color of the emission of a molecule[1,2]. The amplified light emission of the molecule enables us to image the coherent dipole-dipole interaction between molecules[3]. Moreover, we found that the NCP can even produce a completely new physical process, namely the nonlinear inelastic electron scattering[4]. We have also developed a new theory that takes into account the locality of the highly confined field to describe the light-matter interaction[4], which has successfully reproduced experimentally observed super high spatial resolution Raman images of a molecule, below one nanometer [5]. It is found that the non-resonant Raman images should be capable of revealing the vibrational modes of the molecule in real space[4b].
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- Y. Zhang, et al., Nature, 531 (2016) 623
- C.K. Xu, et al. Nature Physics, 10 (2014) 753.
- (a) S. Duan, et al., J. Am. Chem. Soc., 137(2015) 9515; (b) S. Duan, et al., Angew. Chem. Int. Ed., 128 (2016) 1053.
- R. Zhang, et al. Nature, 498 (2013) 82; S. Jiang, et al. Nature Nanotechnology, 10, (2015) 865