Broadband terahertz circular polarizers with single- and double-helical array metamaterials

Area of Science:

• Electromagnetism
• Metamaterials
• Terahertz Technology

Background:

• Circular polarizers are crucial for controlling the polarization state of electromagnetic waves.
• Terahertz (THz) frequency range presents unique challenges and opportunities for wave manipulation.
• Metamaterials offer engineered electromagnetic properties not found in natural materials.

Purpose of the Study:

• To propose and investigate a new broadband terahertz circular polarizer utilizing a double-helix structure.
• To systematically compare the performance of double-helix and single-helix circular polarizers.
• To analyze the influence of structural parameters on polarizer performance.

Main Methods:

• Numerical simulations were employed to evaluate the performance of both single- and double-helix designs.
• Systematic analysis of performance variations based on different structural parameters.
• Theoretical interpretation using antenna theory and metal wire grating theory.

Main Results:

• The proposed double-helix circular polarizer demonstrates a functional region approximately 50% broader than single-helix counterparts in the terahertz spectrum.
• Performance dependencies on various structural parameters were identified for both helix configurations.
• Theoretical frameworks successfully explained observed performance changes and differences between single and double helix structures.

Conclusions:

• The double-helix structure represents a significant advancement for broadband terahertz circular polarizers.
• The enhanced bandwidth achieved by the double-helix design offers improved capabilities for terahertz applications.
• Understanding parameter dependencies is key to optimizing future terahertz polarizer designs.