IMPEDANCE MATCHING ANALYSIS OF AN OPTICAL NANOCIRCUIT FED BY AN APERTURE PROBE
Keywords:Near-field optical probe, nanoantennas, optical nanocircuit, impedance matching, method of moments (MoM)
In this paper, we analyze a near-field optical probe based on nanoantenna, where an aperture probe is coupled to a nanoantenna system. The nanoantenna system considered is an optical nanocircuit composed by a receiving and an emitting dipole connected by a two-wire optical transmission line. In the transmitting mode, we model the coupling between the aperture probe and the receiving dipole by an equivalent voltage source, and then we use the classical antenna theory to make the input impedance matching to optimize the energy transfer in the nanocircuit. The numerical electromagnetic analysis of this circuit is performed by a simple and efficient computational method to analyze plasmonic nanoantennas, based on the linear method of moments. Some results are also calculated with the software Comsol. The analysis is performed in the near-infrared and lower optical frequencies (100-400THz). The results present the spectral variation of the induced current, near field distributions, and reflection coefficient for different geometric parameters. We present some conclusions about the conditions where we have better impedance matching.Â
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