Optical chiral gain-tunable metasurface electric field enhancement devices

Abstract

Nanostructured optical field enhancements have become more attractive in recent years. In this work, we proposed a surface electric field enhancement device based on the combined effect of surface plasmons resonance and surface plasmon polariton. By optimizing the relationship between the morphology of the nanostructures and the Z-direction electric field components, the intensity of the surface polarized plasmons of the meta-atom can be further enhanced. The 633 nm left-circularly polarized light excitation for this device was examined and worked well. It was used as the operating wavelength. A comparison of the results obtained from right-circularly polarized and linearly polarized lights demonstrated only a strong optical field enhancement of the structure with left-handed polarized light. The polarization-selective parameters were also considered. Finally, by designing meta-atoms with different arrangements, we achieved electric field enhancements up to 177.5. It is worth mentioning that this method can control the degree of electric field enhancement by controlling the number of meta-atoms that excite surface plasmon polaritons, which means that obtaining the desired electric field amplitude becomes tunable in the design. With the proper format, the enhancement factor of the surface-enhanced Raman spectroscopy can be increased to approximately 109. In the research of surface-enhanced Raman spectroscopy and optical tweezers, it would be a straightforward and effective design method to create the desired optical field enhancements.