Correlation between single-cylinder properties and bandgap formation in photonic structures

Area of Science:

• Photonics and Metamaterials
• Condensed Matter Physics
• Electromagnetism

Background:

• Photonic structures exhibit frequency gaps crucial for controlling light propagation.
• Understanding gap formation mechanisms in periodic, quasi-periodic, and random structures is essential.
• Dielectric cylinder arrangements are common in photonic device designs.

Purpose of the Study:

• Investigate the origin of frequency gaps in dielectric cylinder photonic structures.
• Analyze the influence of cylinder properties and arrangement on gap formation.
• Differentiate polarization-dependent effects on bandgap characteristics.

Main Methods:

• Numerical simulations of photonic structures with varying cylinder arrangements.
• Analysis of dispersion relations for TM (transverse magnetic) and TE (transverse electric) polarizations.
• Correlation of bandgap properties with Mie resonance characteristics of individual dielectric cylinders.

Main Results:

• For TM polarization, frequency gap formation strongly correlates with single dielectric cylinder Mie resonances, affecting spectral position and size.
• For TE polarization, Mie resonances are spectrally broad, showing no clear correlation with bandgap formation.
• In inverted structures (air cylinders in dielectric), frequency gaps are primarily determined by spatial arrangement due to the absence of pronounced Mie resonances.

Conclusions:

• Single scatterer properties, specifically Mie resonances, are critical for TM polarization bandgap formation in dielectric cylinder photonic crystals.
• Polarization-dependent behavior highlights the distinct physical mechanisms governing light interaction with photonic structures.
• The findings offer insights for designing photonic devices with tailored frequency gaps.