Circular Bragg grating resonators for optical read-out of NV centres in nanodiamonds encapsulated in silicon nitride

Efficient extraction of photons coming from solid-state spin systems is one of the main challenges when aiming to increase the size and complexity of quantum information protocols using these type of systems. An example of this is the read-out of photoluminescence from an NV centres in plain bulk diamond. Due to the refractive index contrast, only a fraction of the light coming from the defect can be collected. Several top-down fabrication...