Breakdown of the effective medium theory: a perspective from Goos-Hänchen shift

Area of Science:

• Optics and Photonics
• Electromagnetism
• Materials Science

Background:

• Effective Medium Theory (EMT) simplifies electromagnetic response calculations.
• EMT is generally exact for all-dielectric systems with deep-subwavelength components.
• The Goos-Hänchen (GH) shift is sensitive to Fresnel reflection coefficients.

Purpose of the Study:

• Investigate the breakdown of EMT in multilayered dielectric structures using the GH shift.
• Explore the applicability of GH shift for nano-meter scale thickness sensing.
• Provide guidance for reducing electromagnetic response calculation errors.

Main Methods:

• Performing Goos-Hänchen (GH) shift calculations on multilayered dielectric structures.
• Analyzing the dependence of GH shift on polarization angle, layer properties, and filling fraction.
• Comparing GH shift results with predictions from EMT.

Main Results:

• The GH shift invalidates EMT in multilayered dielectric structures under common conditions.
• Breakdown of EMT is highly sensitive to the phase and magnitude of the Fresnel reflection coefficient.
• GH shift exhibits strong dependence on incidence polarization, layer, and filling fraction.

Conclusions:

• The GH shift reveals limitations of EMT in specific dielectric structures.
• GH shift is a promising tool for nano-meter scale thickness sensing, surpassing EMT in certain scenarios.
• Findings aid in accurate electromagnetic response calculations and precise metrology device design.