Reading through the Wikipedia article for nitrogen-vacancy centers, is the quantum state of the electron entangled with the other electrons in the nitrogen atom's orbits? I'm trying to understand what fluoresces for measurement, is it the vacancy filling electron, or the electrons transitioning in the orbits of the nitrogen atom. Fascinating, I'm trying to connect the fluorescing response with the spin of the electron. I'm guessing microwaves are use to provide energy to the system, and ultraviolet sensors to measure?

https://en.wikipedia.org/wiki/Nitrogen-vacancy_center