Small-volume waveguide-section high Q microcavities in 2D photonic crystal slabs

Area of Science:

• Photonics
• Materials Science
• Condensed Matter Physics

Background:

• Photonic crystal slabs offer unique light manipulation properties.
• Microcavities are essential for confining light in photonic devices.
• Achieving high Q factors and small modal volumes simultaneously is a key challenge.

Purpose of the Study:

• To investigate a series of microcavities in 2D hexagonal lattice photonic crystal slabs.
• To analyze the trade-offs between Q factor and effective modal volume.
• To identify cavity designs suitable for advanced photonic applications.

Main Methods:

• Utilizing finite difference time domain (FDTD) simulations.
• Analyzing microcavities within a photonic crystal waveguide structure.
• Characterizing Q factor and effective modal volume of cavity modes.

Main Results:

• Preservation of high Q modes with consistent geometrical parameters and field profiles.
• Gradual reduction in effective modal volume across the microcavity series.
• Achieved vertical Q value > 10^6 with effective modal volume ~5.40 (λ/2n_slab)^3.
• Obtained smaller modal volume ~2.30 (λ/2n_slab)^3 with vertical Q value > 10^5.

Conclusions:

• The studied microcavities effectively confine light with high Q factors.
• A design pathway exists for reducing modal volume while maintaining high Q.
• These findings are promising for miniaturized and efficient photonic integrated circuits.