Nanoscopy through a plasmonic nanolens

Abstract

Plasmonics now delivers sensors capable of detecting single molecules. The emission enhancements and nanometer-scale optical confinement achieved by these metallic nanostructures vastly increase spectroscopic sensitivity, enabling real-time tracking. However, the interaction of light with such nanostructures typically loses all information about the spatial location of molecules within a plasmonic hot spot. Here, we show that ultrathin plasmonic nanogaps support complete mode sets which strongly influence the far-field emission patterns of embedded emitters and allow the reconstruction of dipole positions with 1-nm precision. Emitters in different locations radiate spots, rings, and askew halo images, arising from interference of 2 radiating antenna modes differently coupling light out of the nanogap, highlighting the imaging potential of these plasmonic “crystal balls.” Emitters at the center are now found to live indefinitely, because they radiate so rapidly.

Efficient Generation of Two-Photon Excited Phosphorescence from Molecules in Plasmonic Nanocavities

“…The collection C s = 0.67 comes from Lambertian emission with 5% losses and the solid angle restricted by total internal reflection at the glass–air interface, while C N = 0.55 is given by the predominantly high angle emission of the NPoM collected by the same NA = 0.9 objective. 44 , 45 …”

“…The ratio between experiments and simulations can be accounted for by less controlled experimental parameters such as in-/out-coupling efficiencies of the NPoM, orientation, and spatial distribution of molecules in the gap. 44 …”

Dynamics of deterministically positioned single‐bond surface‐enhanced Raman scattering from DNA origami assembled in plasmonic nanogaps

“…We assemble NPoM [ 23,27–29 ] constructs (Figure 1a) using deoxyribonucleic‐acid origami (DNAo) technology and extend it to place individual molecules at the sites of interest. As previously demonstrated, [ 23,30 ] DNAo is a powerful tool to reliably and consistently construct such architectures.…”

“…It is important to notice that the simulated EF of 10 6 is not sufficient to observe single‐molecule SERS and that greater than 90% of the EM field in the gap is polarized along the z ‐direction normal to the metal facets. [ 29,39 ]…”

Imaging and Localization of Single Emitters near Plasmonic Particles of Different Size, Shape, and Material

“…In the context of faithful super-resolution microscopy on particles, the problem has been studied by coupling emitters to silver and gold spheres, 18 , 21 , 22 triangles, 19 nanorods, 16 , 20 , 27 nanoislands, 18 , 28 nanowires, 15 , 17 , 29 − 31 and particle-on-film systems. 32 The modification of the PSF has further been explored from a theoretical point of view by using analytical approximations 33 or numerical simulations for spheres, 34 nanorods, 16 and triangles. 19 In some studies mislocalization was observed as a dominant effect, 16 , 18 − 22 other studies reported it to be negligible compared to the localization precision of the microscope, 4 , 35 and some studies reported exotic multilobed PSFs.…”