Coupling of Nitrogen-Vacancy Centers to Photonic Crystal Cavities in Monocrystalline Diamond

Abstract

The zero-phonon transition rate of a nitrogen-vacancy center is enhanced by a factor of ∼ 70 by coupling to a photonic crystal resonator fabricated in monocrystalline diamond using standard semiconductor fabrication techniques. Photon correlation measurements on the spectrally filtered zero-phonon line show antibunching, a signature that the collected photoluminescence is emitted primarily by a single nitrogen-vacancy center. The linewidth of the coupled nitrogen-vacancy center and the spectral diffusion are characterized using high-resolution photoluminescence and photoluminescence excitation spectroscopy.Nitrogen-vacancy (NV) centers in diamond represent one of the best test-beds for future quantum photonic technologies [1, 2] due to their outstanding properties as spin qubits [3] that can be coupled to optical photons [4]. Applications include quantum information [5] and electro-magnetic field sensing [6][7][8]. For quantum information applications, multiple NV centers need to be interconnected. One approach relies on integrating NVs in photonic networks, where large-scale entanglement between NV centers is created using interference of identical photons at the zero-phonon line (ZPL) frequency. However, in bulk diamond the ZPL transition accounts for only a few percent of the NV emission. Here we report ∼ 70 fold enhancement of the transition rate through the ZPL for a single NV coupled to a photonic crystal cavity in monocrystalline diamond. These cavities are fabricated using scalable semiconductor fabrication techniques and can be further coupled into photonic networks [2].The spontaneous emission rate enhancement of a particular dipole transition i of an emitter coupled to a microresonator relative to the uniform dielectric medium of the resonator is enhanced by the factor τ0where 1/τ 0 is the emission rate in the uniform dielectric medium, 1/τ leak is the emission rate outside the cavity mode, and

Decay of the rotary echoes for the spin of a nitrogen-vacancy center in diamond

“…Among these systems, the nitrogen-vacancy (NV) centers in diamond exhibit a set of particularly desirable features: individual centers can be initialized and read out optically, 1-4 possess naturally long coherence times even at room temperature, [5][6][7] and can be controlled 8 using magnetic fields, 9-12 optical excitations, [13][14][15][16][17] and electric fields. [18][19][20] As a result, the NV centers have attracted much attention as prospective qubits for quantum information processing, 4,7,15,16,[21][22][23][24][25] and as nanoscale sensors. 20,[26][27][28][29][30][31][32][33][34][35][36][37][38] Efficiency of the NV-based devices critically depends on the NV spin coherence time, which is controlled by the coupling to the spins of substitutional nitrogen atoms and/or to the bath of 13 C nuclear spins.…”

High quality-factor optical nanocavities in bulk single-crystal diamond

“…For the most part, these efforts have involved heterogeneous integration of single-crystal diamond slabs (B5-to 30-mm thick) on supporting silica substrates, with subsequent oxygen plasma etching to thin the slab near a target thickness B500-nm or less. Ring resonators [12][13][14][15] and photonic crystal cavities 16,17 have been realized in such thinned diamond membranes, with recent results 18 demonstrating ultrahigh-quality factors (Q) in excess of 10 6 . While this approach remains promising 19 , complications due to material handling, scalability, repeatability and sheer difficulty of removing tens of microns of diamond while preserving uniform hundred-nanometre scale films limit this approach significantly.…”

Generation of entangled photon strings using NV centers in diamond

“…For example it was recently shown in NV coupled photonic crystal cavity experiment [21] that in the presence of a cavity 70% of the emission would be in the ZPL, and with an achievable collection efficiency of ∼ 90% ZPL photons we achieve a 10-photon entangled state per second.…”