Fundamental absorption bandwidth to thickness limit for transparent homogeneous layers

Area of Science:

• Electromagnetics and Materials Science
• Applied Physics

Background:

• Previous research established limits for metal-backed absorbers relating minimal thickness to bandwidth.
• A similar universal relationship for non-metal-backed absorbers was previously lacking.

Purpose of the Study:

• To derive and present a universal relationship for the minimal layer thickness to bandwidth ratio for non-metal-backed absorbers.
• To establish more general fundamental limits on electromagnetic absorber performance.

Main Methods:

• Utilized the Kramers-Kronig relations to develop the theoretical framework.
• Validated the theory using transfer matrix calculations for homogeneous materials.
• Confirmed results with full-wave numerical simulations of electromagnetic metamaterials.

Main Results:

• Established a universal relationship for the minimal layer thickness to bandwidth ratio applicable to non-metal-backed absorbers.
• Demonstrated that this relationship provides more general fundamental limits compared to previous work.

Conclusions:

• The derived universal relationship offers fundamental limits for a broader class of absorbers.
• Findings are significant for both fundamental understanding and practical design of electromagnetic absorbers.