Computational Design of a Split Cavity with Localized Independent Electric Field Tunability

Cavity-mediated strong coupling is an essential element for quantum photonic technologies, but there are multiple challenges to creating scalable device platforms in which multiple matter-based qubits can be strongly coupled to a single cavity. Among these challenges is the inherent inhomogeneity in ensembles of matter-based qubits, which necessitates independent tuning of each qubit into resonance with the mode of the cavity. We present a new design for a photonic crystal split cavity that enables independent electric field tuning of two distinct qubits based on indium arsenide quantum dots in a gallium arsenide heterostructure. Using finite difference time domain simulations, we alter the cavity geometry and the local arrangement of photonic crystal holes to optimize the cavity quality factor. We achieve a simulated quality factor of 20,000, which is comparable to values that have been used to demonstrate strong coupling. We further show that distinct electric fields can be applied to the two qubits with negligible cross talk. The result demonstrates the viability of a new approach to coupling multiple qubits to a single cavity and opens the door for both further numerical optimization and experimental realization of this new paradigm.