Hybrid mesoscale-structures that can combine dielectric optical resonances with plasmon-polaritons are of interest in chip-scale nano-optical communication and sensing. This experimental study shows how a fluorescent microsphere coupled to a silver nanowire can act as a remotely-excited optical antenna. To realize this architecture, self-assembly methodology is used to couple a fluorescent silica microsphere to a single silver nanowire. By exciting propagating surface plasmon polaritons at one end of the nanowire, remote excitation of the Stokes-shifted whispering gallery modes (WGMs) of the microsphere is achieved . The WGMmediated fluorescence emission from the system is studied using Fourier plane optical microscopy, and the polar and azimuthal emission angles of the antenna are quantified.Interestingly, the thickness of the silver nanowires is shown to have direct ramifications on the

Group‐IV monochalcogenides have emerged with immense potential to be used as ferroelectric materials in recent times. However, in most of them, ferroelectricity is limited by the presence of inversion symmetry in their natural crystal structure. Here, an experimental observation of ferroelectric order at room temperature by introducing Eshelby twist in Germanium sulfide (GeS) nanowires is reported. The twisted nanowires are synthesized by low‐pressure chemical vapor deposition. The existence of room temperature ferroelectricity in a single nanowire is confirmed by electrical measurements, piezoelectric force microscopy, and second harmonic generation spectroscopy. Density functional theory calculations reveal that the twist in the GeS nanowires breaks the inversion symmetry where the inversion symmetry breaking phonon modes get hardened giving rise to ferroelectricity. These results are expected to be useful in making non‐volatile memory devices, flexible electronics, electronic sensors, and neuromorphic computing.

We report an experimental observation of the transverse spin and associated spin-momentum locking of surface plasmon polaritons (SPPs) excited in a plasmonic single crystalline silver nanowire (AgNW). In contrast to the SPPs excited in metal films, the electromagnetic field components of the evanescent SPP mode propagating along the long axis (x axis) of the NW can decay along two longitudinal planes (x–y and x–z planes), resulting in two orthogonal transverse spin components (sz and sy). Analysis of the opposite circular polarization components of the decaying SPP mode signal in the longitudinal plane (x–y) reveals spin dependent biasing of the signal and, hence, the existence of transverse spin component (sz). The corresponding transverse spin density (s3) in the Fourier plane reveals spin-momentum locking, where the helicity of the spin is dictated by the wave-vector components of the SPP evanescent wave. Furthermore, the results are corroborated with three-dimensional numerical calculations. The presented results showcase that how a chemically prepared plasmonic AgNW can be harnessed to study optical spins in evanescent waves and can be extrapolated to explore sub-wavelength effects, including directional spin coupling and optical nano-manipulation.

No abstract

No abstract