title: Nanoengineered diamond waveguide as a robust bright platform for nanomagnetometry using shallow nitrogen vacancy centers.
abstract: Photonic structures in diamond are key to most of its application in quantum technology. Here, we demonstrate tapered nanowaveguides structured directly onto the diamond substrate hosting shallow-implanted nitrogen vacancy (NV) centers. By optimization based on simulations and precise experimental control of the geometry of these pillar-shaped nanowaveguides, we achieve a net photon flux up to ∼ 1.7 × 10(6) s(-1). This presents the brightest monolithic bulk diamond structure based on single NV centers so far. We observe no impact on excited state lifetime and electronic spin dephasing time (T2) due to the nanofabrication process. Possessing such high brightness with low background in addition to preserved spin quality, this geometry can improve the current nanomagnetometry sensitivity ∼ 5 times. In addition, it facilitates a wide range of diamond defects-based magnetometry applications. As a demonstration, we measure the temperature dependency of T1 relaxation time of a single shallow NV center electronic spin. We observe the two-phonon Raman process to be negligible in comparison to the dominant two-phonon Orbach process.
authors.affiliation: 3. Institute of Physics, Research Center SCoPE and IQST, University of Stuttgart , 70569 Stuttgart, Germany.
authors.forename: S Ali
authors.initials: SA
authors.lastname: Momenzadeh
authors.forename: Rainer J
authors.initials: RJ
authors.lastname: Stöhr
authors.forename: Felipe Favaro
authors.initials: FF
authors.lastname: de Oliveira
authors.forename: Andreas
authors.initials: A
authors.lastname: Brunner
authors.forename: Andrej
authors.initials: A
authors.lastname: Denisenko
authors.forename: Sen
authors.initials: S
authors.lastname: Yang
authors.forename: Friedemann
authors.initials: F
authors.lastname: Reinhard
authors.forename: Jörg
authors.initials: J
authors.lastname: Wrachtrup
keywords: Shallow nitrogen vacancy center; T2 dephasing time; diamond tapered nanopillar; low temperature T1 relaxation time; nanofabrication