Single NV centers in nanodiamond as three dimensional scanning lifetime probe

Control over the electromagnetic environment is one of the key requirements for optical nanotechnology. Knowledge of the local density of optical states (LDOS) is on one hand important for design and optimization of photonic devices and on the other hand indispensable for the understanding of fundamental optical interactions. The changes of the excited state lifetime of an emitter can be used to probe the LDOS [1,2]. A versatile probe for the LDOS is the nitrogen vacancy centers (NV centers) in diamond. Being photostable and appearing in nanocrystals it is ideally suited to be manipulated with an atomic force microscope in a controlled way [3]. When a nanodiamond is glued to the tip of an atomic force microscope, its coupling to other structures can be adjusted in all three dimensions. Here, this is used in a systematic manner to obtain detailed three dimensional information about the optical density of states in the vicinity of different plasmonic structures via scanning the diamond and recording data simultaneously. Only nanodiamonds with a single NV center emitting single photons were used to obtain the best resolution for both, lifetime and space.