Structural Design and Optimization of Optical Nano-antenna Based on Bridge Structure

This is the authors' abstract. We don't add key points for this paper.

Optical nano-antenna offers a new scheme for solar energy collection by breaking through the band-gap limitation of semiconductor materials.However, complex structure, low efficiency, and narrow bandwidth remain major issues.To address these problems, we propose a novel helical optical nano-antenna based on the bridge structure.The antenna structure consists of two coplanar Archimedes spiral arms and a base layer.We analyze the influence mechanism of structural factors on its radiation efficiency and polarization characteristics.Our results show that the antenna structure achieves a total radiation efficiency of 83.13% in the wide wavelength range of 400 to 1600 nm, which is significantly higher than that of the previously proposed dipole nano-antenna.For different linearly polarized incident waves, the antenna structure obtains the same order electric field at the spiral gap, which indicates that the antenna structure can fully consider the polarization characteristics of sunlight.It fundamentally solves the problem that the linearly polarized antenna can only receive half of the solar energy, improving the absorption efficiency.