Active Polarization Control with a Parity-Time Symmetric Plasmonic Resonator

Abstract

Control of the polarization state of light is essential for many technologies, but is often limited by weak light-matter interactions that necessitate long device path lengths or significantly reduce the signal intensity. Here, we investigate a nanoscale plasmonic aperture capable of modifying the polarization state of far-field transmitted light without loss in the probe signal. The aperture is a coaxial resonator consisting of a dielectric ring embedded within a metallic film; parity-time ($\mathcal{P}\mathcal{T}$) symmetric inclusions of loss and gain within the dielectric ring enable polarization control. Since the coaxial aperture enables near-thresholdless $\mathcal{P}\mathcal{T}$ symmetry breaking, polarization control is achieved with realistic levels of loss and gain. Exploiting this sensitivity, we show that the aperture can function as a tunable waveplate, with the transmitted ellipticity of circularly polarized incident light changing continuously with the dissipation coefficient from $\pi /2$ to 0 (i.e. linear polarization). Rotation of linearly polarized light with unity efficiency is also possible, with a continuously-tunable degree of rotation. This compact, low-threshold, and reconfigurable polarizer may enable next-generation, high-efficiency displays, routers, modulators, and metasurfaces.

References in corpus (8)

• Unidirectional Nonlinear PT-symmetric Optical Structures
• Design of Tunable Biperiodic Graphene Metasurfaces
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• Electro-optical switching by liquid-crystal controlled metasurfaces
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Cited by in corpus (4)

• Non-Hermitian Physics
• Parity-Time Symmetry in Non-Hermitian Complex Optical Media
• Single-mode lasers using parity-time-symmetric polarization eigenstates
• Bound states in the continuum and exceptional points in dielectric waveguide equipped with a metal grating