# Suppressed Transmission of Long-Range Surface Plasmon Polariton by TE-Induced Edge Plasmon
## 1 Introduction  
Plasmonic materials, including metals below the plasma frequency, have an inherent ability to squeeze light within deep-subwavelength volumes through the kinetic energy of free carriers inside the material [1]. By virtue of this free electron contribution, the diffraction limit of light can be overcome [2]. Plasmonic materials have also been widely exploited in nanophotonic applications such as biosensing [3], lithography [4], display [5], second harmonic generation [6] and optical trapping [7]. Surface plasmons (SPs) are coherent charge density oscillations localized to the interface between the positive and negative permittivity materials, and they channel absorbed electromagnetic energy to free electrons. Further, resonant coupling between longitudinal SP waves and electromagnetic waves forms propagating surface plasmon polaritons (SPPs) along the interface [8].  
SPPs are regarded as promising information carriers for the next generation of integrated circuits because a broad range of mode sizes can be realized through waveguide configurations [9, 10, 11] or phase control [12, 13], and it can be detected on-chip directly, by electrical means [14, 15] and by out-coupled (far-field) optical detection. The quantum properties of a photon-pair, including entanglement, can be preserved even in the conversion of photons into SPPs (photon-SPP), and vice versa (SPP-photon) [16, 17]. A high bit-rate and the WDM data transmission over plasmonic waveguides were well demonstrated with low bit error rates [18, 19] and there have been many efforts to develop waveguide-based plasmonic devices, for example the demultiplexer [20], a mode converter [21, 22, 12, 23], a coupler [24, 25], and a logic gate [26], as building blocks for nanoplasmonic integrated circuits (NPICs).  
The control of the propagation of SPPs with external stimuli has attracted much attention for realizing SPP-based optical isolation, nonreciprocity and signal generation in NPICs. It has been found that drifting electrons using an external electric current [27; 28; 29; 30; 31] or static magnetic field [32; 33; 34] causes an asymmetric dispersion and the nonreciprocity of SPPs. In addition, the modulation of SPPs at the single metal-dielectric interface was demonstrated using a gate-biased field effect [35] and a light pulse [36; 37]. In our recent study [38], we proposed that using a long-range SPP (LRSPP) as a carrier wave, a plasmonic signal can be invertedly copied from a modulated optical signal, through use of a plasmonic signal copier (PSC). Herein, we investigated the plasmonic response in the dielectric gap of a PSC for polarization power of the input optical signal, numerically and experimentally. Highly confined edge plasmon is only excited for TE-polarized optical signals, and induces strong electric currents inside the plasmonic waveguides, leading to the suppressed transmission of LRSPPs. Considering the dependence of the input optical power and the electric permittivity change on the dielectric material near the gap on plasmonic signals in a PSC, a discussion regarding the efficient control of SPPs with light is also presented.