Rod and slit photonic crystal microrings for on-chip cavity quantum electrodynamics

Area of Science:

• Optics and Photonics
• Quantum Technologies
• Materials Science

Background:

• Micro-/nanocavities are essential for enhancing light-matter interactions in cavity quantum electrodynamics (cQED).
• Whispering gallery mode (WGM) resonators offer high quality factors (Q) but limited mode volumes (V).
• Photonic crystal (PhC) cavities provide smaller V but demand stringent design and fabrication control for high Q.

Purpose of the Study:

• To introduce novel photonic crystal ring (PhCR) designs combining WGM and PhC advantages for cQED.
• To develop PhCRs with traditional unit cells suitable for solid-state cQED applications.
• To achieve enhanced modal confinement and maintain high Q factors in PhCRs.

Main Methods:

• Design and simulation of two novel PhCR geometries: 'rod' and 'slit' unit cells.
• Analysis of Q factors, mode volumes (V), and WGM coupling properties.
• Evaluation of suitability for integration with quantum nodes (e.g., quantum dots, spins).

Main Results:

• Both rod and slit PhCRs demonstrate high Q factors and preserved WGM coupling.
• Rod PhCRs exhibit an additional ~10x reduction in V through defect localization.
• Slit PhCRs show co-existing fundamental and 2nd-order PhC modes with high Q and good coupling.

Conclusions:

• Novel rod and slit PhCR designs are suitable for solid-state cQED.
• These PhCRs offer a promising platform for high-Q/V microcavities.
• The designs are straightforward to fabricate, facilitating cQED research.