Alignment-free coupling to arrays of diamond microdisk cavities with fabrication tolerant spin-photon interfaces

We propose a design for an efficient spin -photon interface to a color center in a diamond microdisk. The design consists of a silicon oxynitride triangular lattice overlaid on a diamond microdisk without any aligmnent between the layers. This enables vertical emission from the microdisk into low -numerical aperture modes, with quantum efficiencies as high as 46% for a tin vacancy (SnV) center. Our design is robust to manufacturing errors, potentially enabling large scale fabrication of quantum emitters coupled to optical collection modes. We also introduce a novel approach for optimizing the free space performance of our device using a dipole model, achieving comparable results to full -wave finite difference time domain simulations with 7 center dot 106 reduction in computational time.