Dispersion-guided resonances in two-dimensional photonic-crystal-embedded microcavities

Area of Science:

• Photonics
• Optical Engineering
• Materials Science

Background:

• Photonic-crystal-embedded microcavities (PCEMs) offer unique optical properties.
• Guiding resonances in these structures is crucial for device applications.

Purpose of the Study:

• To analyze dispersion-based guiding of resonances in 2D PCEMs.
• To investigate factors influencing the quality factor (Q) of these resonances.

Main Methods:

• Utilized 2D finite-difference time-domain (FDTD) simulations.
• Analyzed waveguide side-coupled PCEMs with square lattices of air holes.
• Mapped Fourier transforms of mode-field distributions to the photonic crystal dispersion surface.

Main Results:

• Identified high-Q quasi-periodic multimodes within the first photonic crystal band.
• Observed Q factor increases by orders of magnitude near the band-edge frequency.
• Demonstrated Q factor enhancement with increasing lattice dimension.
• Showed mode k-vectors and group velocities align near the GammaM direction.

Conclusions:

• Dispersion-based guiding effectively controls resonances in 2D PCEMs.
• Band-edge proximity and lattice size are key parameters for enhancing Q factors.
• Understanding mode propagation near GammaM is vital for PCEM design.