Plasmonic mode converter for controlling optical impedance and nanoscale light-matter interaction

Abstract

Abstract:To enable multiple functions of plasmonic nanocircuits, it is of key importance to control the propagation properties and the modal distribution of the guided optical modes such that their impedance matches to that of nearby quantum systems and desired light-matter interaction can be achieved. Here, we present efficient mode converters for manipulating guided modes on a plasmonic two-wire transmission line. The mode conversion is achieved through varying the path length, wire cross section and the surrounding index of refraction. Instead of pure optical interference, strong near-field coupling of surface plasmons results in great momentum splitting and modal profile variation. We theoretically demonstrate control over nanoantenna radiation and discuss the possibility to enhance nanoscale light-matter interaction. The proposed converter may find applications in surface plasmon amplification, index sensing and enhanced nanoscale spectroscopy.

Coherent Control of Plasmon Propagation in a Nanocircuit

“…1(a)] and an antisymmetric [quasi-TE, Fig. 1(b)] eigenmode [23,25]. As shown recently [23], pure eigenmodes can be excited with equal amplitude if an appropriate incoupling antenna [20] is attached to the two-wire transmission line and is illuminated by a well-positioned linearly polarized laser spot.…”

Design of Compact TE-Polarized Mode-Order Converter in Silicon Waveguide With High Refractive Index Material

“…Typically, mode conversion can be divided into three types, including photonic to photonic mode, plasmonic to plasmonic mode [6]- [9], and photonic to plasmonic mode [10]- [13]. The photonicto-photonic mode conversion mainly consists of mode-order converters and polarization rotators [14]- [18].…”

Tunable spatial mode converters and optical diodes for graphene parallel plate waveguides

“…These devices are based on unidirectional mode conversion which is achieved through the spatiotemporal modulation of graphene's conductivity [34]. Several different mode converters based on photonic crystal, silicon, metalinsulator-metal, and nanowire waveguides have also been proposed, and their connection to multiplexing and all-optical diodes have been investigated [33,[35][36][37][38][39][40][41][42]. Recently, an all-optical modal isolator based on a multimode silicon waveguide was designed and fabricated by Feng et al [43].…”