Abstract Here, Graphene clad plasmonics waveguide is introduced as a two surface plasmonic polariton modes interference (GTSPPMI) coupler to obtain optically manipulated quantum interference. The manipulation of Handel Ou Handel (HOM) quantum interference is demonstrated theoretically in nano-scale two modes coupler through refractive index modulation in Graphene clad with incidence of an ultra fast optical pulse energy. The quantum entanglement of fidelity ~ 97.5% is obtained by incidence of optical pulse of energy 5.12 pJ and width 3.8 ps in Graphene cladding. Our results promise to obtain fast and compact optical reconfiguring of quantum plasmonics circuit in comparison to electrooptic and themooptic coupler.
Abstract Here, Graphene clad plasmonics waveguide is introduced as a two surface plasmonic polariton modes interference (GTSPPMI) coupler to obtain optically manipulated quantum interference. The manipulation of Handel Ou Handel (HOM) quantum interference is demonstrated theoretically in nano-scale two modes coupler through refractive index modulation in Graphene clad with incidence of an ultra fast optical pulse energy. The quantum entanglement of fidelity ~ 97.5% is obtained by incidence of optical pulse of energy 5.12 pJ and width 3.8 ps in Graphene cladding. Our results promise to obtain fast and compact optical reconfiguring of quantum plasmonics circuit in comparison to electrooptic and themooptic coupler.
We propose a scheme for achieving quantum entanglement between surface-plasmon-polariton (SPP) modes in a hybrid plasmonic-graphene waveguide system. We then demonstrate that the entanglement of two SPP modes can serve as a useful resource for quantum communication of continuous-variable light signals over a long distance, mediated by concatenated swap operations. The teleportation fidelity of an unknown coherent state has strong robustness to loss and imperfect detection at relatively strong effective optical-microwave coupling. Our study opens the way for continuous-variable quantum communication and quantum information based on hybrid plasmonic-graphene systems.
We propose a novel approach for microwave and optical fields entanglement using an electrical capacitor loaded with graphene plasmonic waveguide. In the proposed scheme, a quantum microwave signal of frequency ωmdrives the electrical capacitor, while an intensive optical field (optical pump) of frequency ω1is launched to the graphene waveguide as a surface plasmon polariton (i.e., SPP) mode. The two fields interact by the means of electrically modulating the graphene optical conductivity. It then follows that an upper and lower SPP sideband modes (of ω2= ω1+ ωmand ω3= ω1- ωmfrequencies, respectively) are generated. We show that the microwave signal and the lower sideband SPP mode are entangled, for a proper optical intensity. A quantum mechanics model is carried out to describe the fields evolution. Furthermore, novel iterative approach (based on combining the Duan criterion with the quantum regression theorem) is developed to assess the fields entanglement. Consequently, the entanglement of the two fields is evaluated versus several parameters including the waveguide length, the pump intensity, and the microwave frequency. We find that the two fields are entangled over a vast microwave frequency range. Moreover, our calculations show that a significant number of entangled photons are generated at the lower SPP sideband. The proposed scheme attains tunable mechanism for microwave-optical entanglement which paves the way for efficient quantum systems.
Surface plasmon polaritons (SPPs) result from collective oscillations of free electrons coupled to an electromagnetic field at a plane interface between a metal and a dielectric medium. As photons, SPPs can be considered either as waves or as bosonic particles [1] and they can experience striking quantum interferences such as Hong-Ou-Mandel (HOM) effect [2]. We use in this paper a plasmonic platform (Fig.1) that can convert photons into plasmons, and separate or recombine them on a plasmonic beamsplitter [3]. Single SPPs are excited using single photons created by parametric down conversion into a periodically-poled KTP crystal. The platform is placed in a Mach-Zehnder interferometer in order to vary the path difference between SPPs before impinging on the beamsplitter. The setup allows us to revisit quantum optics experiments using SPP as carriers of the quantum of energy. Using the same device, we can test the wave-particle duality, two-particle (HOM) interference and non-local control of single plasmon interference using the entanglement between a photon and a SPP [4]. In the case of the HOM experiment, we demonstrate that the losses can be used as a new degree of freedom [5]. Playing with the dephasing between transmission and reflection coefficient of the beamsplitter, we can observe a peak instead of the usually expected dip in the HOM interference (Fig.2), i.e. an anti-coalescence effect of SPP. In this talk, we will introduce the plasmonic device main features as well as the different quantum plasmonics experiments that have been performed thanks to the SPP beamsplitter. These results are essential to understand the SPP quantum behavior or to develop hybrid plasmon-photon systems for potential future applications in quantum communication mediated by SPP. [1] JM Elson and R.H. Ritchie, Phys. Rev. B 4, 4129 (1971) [2] J.S. Fakonas et al., Nat. Phot. 8, 317 (2014) [3] M.C. Dheur et al. , Sc. Advances 2, e151574 (2016) [4] M.C. Dheur et al. ArXiv 1610.07493, B. Vest et al. ArXiv 1610.07479 [5] S. Barnett et al., Phys. Rev. A 57, 2134 (1998) Fig.1: Plasmonic platform used for the quantum optics experiment (B). It consists in two SPP launchers (A), a plasmonic beamsplitter, and two slits to convert SPP to photons in the glass substrate. The plasmonic interference can thus be probed using single photon counting modules. Fig2: HOM experiment on a lossy plasmonic beamsplitter, whose complex amplitude reflection and transmission factors are denoted r and t respectively. The usual HOM dip is observed when r = it (left), a peak in the coincidence rate is shown when r = t.
An experimentally feasible configuration of a prism coupler with an electromagnetically-induced-transparency (EIT) medium layer, e.g., a semiconductor-quantum-dot (SQD) medium, deposited upon its prism base is suggested for generating tunable surface-plasmon-polariton resonance. Such surface-plasmon-polariton resonance and optical excitation of a surface plasmon wave can be manipulated by switchable quantum interference among SQD multilevel transitions driven by two external control fields. When an incident probe field is coupled into a surface plasmon wave excitation mode, the surface-plasmon-polariton (SPP) resonance at the interface between the SQD medium layer and the substrate will arise, and the quantum-coherently controllable reflection spectrum of the probe field on the prism base can be achieved. In this process, destructive and constructive quantum interference (determined by the intensity ratio of the two external control fields) in the SQD multilevel system plays a key role for achieving the tunable reflection spectrum. The EIT-based surface-plasmon-polariton resonance presented here will have three characteristics (some of them would be attractive): (i) switchable quantum interference exhibited by surface plasmon wave excitation, (ii) quantum-coherently controllable surface plasmon polaritons by external optical fields, (iii) surface wave sensitive to dispersion of the SQD quantum coherent medium. Such an effect of controllable optical response based on the quantum-interference switchable surface-plasmon-polariton resonance in the EIT-prism coupler may find some potential applications in design of new photonic and quantum optical devices.
We investigate entanglement mediated by DC current induced nonreciprocal graphene plasmon polaritons. Nonreciprocal systems are ideal for the enhancement, control, and preservation of entanglement due to the potential for unidirectional beam-like wave propagation, i.e., efficiently transporting photons from one emitter to another. Using a quantum master equation and three-dimensional Green's function analysis, we investigate a system consisting of two two-level emitters dominantly interacting via electric current induced nonreciprocal plasmonic modes of a graphene waveguide. We use concurrence as a measure of entanglement. We show that nonreciprocal graphene plasmon polaritons are a promising candidate to generate and mediate concurrence, where it is shown that there is good enhancement and control of entanglement over vacuum, which is beneficial for the broad applications of entanglement as a quantum resource. We believe our findings contribute to the development of quantum devices, enabling efficient and tunable entanglement between two-level systems, which is a central goal in quantum technologies.