LAUSR

We demonstrate the superresolution localization of the nitrogen-vacancy centers in diamond by a fluorescence photoswitching technique based on coherent quantum control. The photoswitching is realized by the quantum phase encoding based on pulsed magnetic field gradient. Then we perform superresolution imaging and achieve a localizing accuracy better than $1.4\phantom{\rule{4pt}{0ex}}\mathrm{nm}$ under a scanning confocal microscope. Finally, we show that the quantum phase encoding plays a dominant role on the resolution, and a resolution of $0.15\phantom{\rule{4pt}{0ex}}\mathrm{nm}$ is achievable under our current experimental condition. This method can be applied in subnanometer scale addressing and control of qubits based on multiple coupled defect spins.