Interaction of an Asymmetric Scanning Near Field Optical Microscopy Probe With Fluorescent Molecules

Abstract

Abstract-We present a numerical analysis of the interaction between novel scanning near field optical microscopy probes based on an asymmetric structure and a single fluorescent molecule. Our finite element analysis shows how such near field probes can be effectively used for high resolution detection of single molecules, in particular those with a longitudinal dipole moment. At the same time, fluorescent molecules can be exploited as point-like probes of the single vectorial components of the near field distribution at the probe apex, providing a powerful tool for near field probe characterization.

Estimating the Reduction of Radiated Emissions From TFT-LCD Panel Using Network Analyzer With a Bulk Current Injection Probe

“…However, performing far-field measurements is very costly and time-consuming. Another common method of measuring PCB radiated emissions is to use a magnetic or electric field probe for near-field scanning of the PCB surface [9][10][11][12][13]. Although the associated test setup and procedure are simpler than those for far-field measurement, the near-field scan results are more effective for locating the source of radiated emission than for predicting radiated emission levels as required by EMC specifications.…”

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Novel SNOM Probes Based on Nanofocusing in Asymmetric Structures

“…For all these reasons, we have investigated the interaction of a single fluorescent molecule with an axisymmetric probe under radially polarized excitation and with an asymmetric probe under linearly polarized excitation in order to identify the similarities between the vectorial components of the near-field distributions close to the apex of the probes [79]. In most of the calculations, we considered the cut probe as an example of asymmetric probe due to the simplicity to fabricate this probe using FIB milling, as will be discussed in the next paragraph.…”

“…Simulated fluorescence intensity maps for single molecules with different orientations (as specified by the polar angle θ and the azimuthal angle φ) excited by a cut probe under linearly polarized excitation along the direction of the asymmetry (x) and located at 10 nm from the tip apex. All the maps are reported on the same colour scale, with each plot normalized to its peak intensity value (adapted from [79]). …”