Polarization-to-Phase Coupling at a Structured Surface for Plasmonic Structured Illumination Microscopy

Polarization-phase interaction on the nanoscale is the cause of many unique effects that are absent or weak in traditional optics. These effects enable various applications in physics, nano-optics, and material science. Here, by making use of a properly designed metasurface, polarization-to-phase coupling in a structured surface is investigated. The wavefront of a surface plasmon polariton (SPP), emitted from the metasurface, can be tuned continuously and linearly by changing the incident polarization along the longitudinal line at the Poincare sphere. This type of phase modulation with polarization enables dynamic control of the wavefront. This is very different from other methods that achieve phase modulation through nano-structures, which offer little room for tuning after the structure has been completed. As a demonstration of application, a plasmonic structured illumination microscope is achieved, where the near-field standing-wave of the SPP is controlled dynamically through the incident polarization. This improves both reliability and stability substantially. Metasurfaces are powerful tools to modulate the wavefront of an electromagnetic field. In combination with structured illumination microscopy (SIM) (the Meta-SIM"), this allows more degrees of freedom and should accelerate the progress of SIM technology.