Photonic crystal defect cavities coupled to N-V centres in diamond

The nitrogen-vacancy (N-V) defect in ultra-pure diamond shows great promise for the implementation of qubits for quantum computing. The N-V defect is a three level system which behaves as an efficient room temperature source of single photons at a wavelength of 637 nm. The N-V centre ground state spin strongly modulates the rate of spontaneous emission providing a mechanism for spin read out. Recently, it is shown that spin-readout with the minimum number of photons can be achieved by efficiently coupling light to the transition in a sub- wavelength scale micro-cavity. The aim of this paper is to place the N-V centre into a cavity at the centre of a suspended slab photonic crystal structure made from hexagonal array of cylindrical air holes. The light is confined by distributed Bragg reflection in the plane of periodicity (xy) and by total internal reflection in the perpendicular plane (z). The work consists of both modelling the photonic crystal to optimise the parameters and fabricating the structures using focussed ion beam milling