title: Magnetic spin imaging under ambient conditions with sub-cellular resolution.
abstract: The detection of small numbers of magnetic spins is a significant challenge in the life, physical and chemical sciences, especially when room temperature operation is required. Here we show that a proximal nitrogen-vacancy spin ensemble serves as a high precision sensing and imaging array. Monitoring its longitudinal relaxation enables sensing of freely diffusing, unperturbed magnetic ions and molecules in a microfluidic device without applying external magnetic fields. Multiplexed charge-coupled device acquisition and an optimized detection scheme permits direct spin noise imaging of magnetically labelled cellular structures under ambient conditions. Within 20 s we achieve spatial resolutions below 500 nm and experimental sensitivities down to 1,000 statistically polarized spins, of which only 32 ions contribute to a net magnetization. The results mark a major step towards versatile sub-cellular magnetic imaging and real-time spin sensing under physiological conditions providing a minimally invasive tool to monitor ion channels or haemoglobin trafficking inside live cells.
authors.affiliation: 3rd Institute of Physics and Research Center SCOPE, University Stuttgart, Stuttgart 70569, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Steinert
authors.forename: F
authors.initials: F
authors.lastname: Ziem
authors.forename: L T
authors.initials: LT
authors.lastname: Hall
authors.forename: A
authors.initials: A
authors.lastname: Zappe
authors.forename: M
authors.initials: M
authors.lastname: Schweikert
authors.forename: N
authors.initials: N
authors.lastname: Götz
authors.forename: A
authors.initials: A
authors.lastname: Aird
authors.forename: G
authors.initials: G
authors.lastname: Balasubramanian
authors.forename: L
authors.initials: L
authors.lastname: Hollenberg
authors.forename: J
authors.initials: J
authors.lastname: Wrachtrup