Efficient miniature circular polarization analyzer design using hybrid spiral plasmonic lens

The spin dependence of the focusing behavior of a spiral slot plasmonic lens can be utilized for a miniature circular polarization analyzer. However, the azimuthal polarization component of the incident circular polarization does not contribute to surface plasmon excitation and focusing because it is TE polarized with respect to the spiral slot. In this Letter, a hybrid metallic lens that consists of alternating spiral triangle array and spiral slot is designed to improve the plasmonic coupling efficiency. The spiral triangle array is responsible for coupling the azimuthal polarization component into surface plasmon. Numerical studies show that the field enhancement at the focus and power conversion efficiency can be increased by 39.53% and 94.69% compared to that of pure spiral slot plasmonic lens.