Numerical Analysis of Protection Method of Metallic Sub-Wavelength Concentric Arrays for Radially Polarized Light...

Area of Science:

• Optics and Photonics
• Nanotechnology
• Materials Science

Background:

• Radially polarized light offers advantages in sensing due to its symmetric field distribution.
• Metallic sub-wavelength concentric arrays are commonly used for selecting radial polarization components.
• Existing nanostructures face challenges with mechanical and chemical stability.

Purpose of the Study:

• To propose and optimize a protective layer for metallic sub-wavelength concentric arrays.
• To enhance the stability and performance of nanostructures for radially polarized light.
• To demonstrate the application of the protected structure in optical components.

Main Methods:

• Numerical calculation and optimization of metallic sub-wavelength concentric arrays with a protective layer.
• Characterization of transmittance for radially polarized light.
• Evaluation of polarization extinction ratio against azimuthally polarized light.
• Fabrication and testing of a binary, concentric optical plate incorporating the structure.

Main Results:

• The optimized structure achieved ~97.4% transmittance for radially polarized light.
• A polarization extinction ratio of ~20 dB was obtained, suppressing the azimuthally polarized component.
• The protective layer resulted in a 22% performance increase compared to unprotected structures.
• The optical plate successfully functioned with radially polarized input while blocking azimuthally polarized input.

Conclusions:

• The proposed protective layer significantly enhances the performance and stability of metallic sub-wavelength concentric arrays.
• The protected structures are suitable for applications in centrosymmetric flat optical components.
• This advancement offers improved selectivity and durability for optical devices utilizing radially polarized light.