Photonic-crystal-fiber-coupled photoluminescence interrogation of nitrogen vacancies in diamond nanoparticles

A photonic-crystal fiber is used to demonstrate a fully fiber-integrated optical interrogation of nitrogen vacancies in diamond nanoparticles, where both pump radiation and the photoluminescent response of nitrogen vacancies are coupled to the fiber modes. A properly designed fiber is shown to provide a high-contrast guided-mode-coupled zero-phonon-line photoluminescent response from nitrogen vacancies, which is at least an order of magnitude higher than the Raman background signal from the fiber.