Optimised chiral light-matter interactions at polarisation singularities for quantum photonics

Photonic crystal waveguides support chiral-point polarisation singularities which give rise to local chirality even in the absence of a global chiral symmetry. Placing a quantum dot at such a C-point gives rise to a uni-directional emission dependent on the electron spin - ideal for applications in quantum information as it entangles the spin direction of electrons on the quantum dot (static qubits) to the path in the waveguide (flying qubits). Here we discuss the optimisation of this chiral light-matter interaction using slow-light waveguides, and show designs with 8.6 times enhancement of the local density of optical states at a C-point.