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The quality factor (Q) of resonators defined in photonic crystal (PhC) membranes is known to be sensitive to the tapering of the air-holes. A small deviation from an ideal structure with perfectly vertical holes can result in orders of magnitude decrease in the Q, hence greatly jeopardizing applications of such devices in the field of cavity quantum electrodynamics (cQED). Tapering breaks the vertical reflection symmetry of the structure, allowing confined TE-like cavity modes to couple to the resonant continuum of lossy TM-like modes. We show, using a combination of finite-difference time-domain (FDTD) modeling and plane wave expansion method (PWE), that the membrane thickness plays a critical role in the mode coupling. By choosing the thickness about a third of the wavelength of the mode, the high Q of a PhC cavity can be restored despite 10 degrees taper. These findings show that high Q resonators relatively insensitive to the tapering are achievable.

Cavities embedded in photonic crystal waveguides offer a promising route towards large scale integration of coupled resonators for quantum electrodynamics applications. Here a strongly coupled system consisting of a single quantum dot and a cavity formed by the local width modulation of a photonic crystal waveguide is demonstrated. The resonance originating from the cavity is clearly identified from microphotoluminescence mapping of the scattered signal along the waveguide. The exciton‐photon strong coupling regime is obtained by temperature control.

We propose a system for scalable on-chip optical QIP using a coupled atom-cavity system in a silicon photonic crystal slab. Device design is optimised using plane wave expansion (PWE) and finite difference time domain (FDTD) simulations, and devices are presented which allow non-intrusive experimental characterisation before and after ion implantation.