Fiberized Diamond-Based Vector Magnetometers

Abstract

We present two fiberized vector magnetic-field sensors, based on nitrogen-vacancy (NV) centers in diamond. The sensors feature sub-nT/Hz magnetic sensitivity. We use commercially available components to construct sensors with a small sensor size, high photon collection, and minimal sensor-sample distance. Both sensors are located at the end of optical fibres with the sensor-head freely accessible and robust under movement. These features make them ideal for mapping magnetic fields with high sensitivity and spatial resolution (≤ mm). As a demonstration we use one of the sensors to map the vector magnetic field inside the bore of a ≥100 mT Halbach array. The vector field sensing protocol translates microwave spectroscopy data addressing all diamonds axes and including double quantum transitions to a 3D magnetic field vector.

Quantum magnetometer based on cross-relaxation resonances in ensembles of NV-centers in diamond

“…In work [12], for example, using a larger diameter fiber and a reflective coating, the resulting photocurrent value (∼ 40 µA) is about three times higher than what we obtained with a similar diamond crystal and pump intensity. Even more promising could be the use of special parabolic condenser [17]. (see, for example, [6]) and/or to increase the size of the active element, which, however, would increase the size of the sensor.…”

Квантовый Магнитометр На Основе Кросс-Релаксационных Резонансов В Ансамбле NV-центров В Алмазе

“…В работе [12], например, используется волокно большего диаметра и светоотражающее покрытие, полученное значение фототока (∼ 40 µA) примерно втрое превышает полученное нами при сходном кристалле алмаза и интенсивности накачки. Еще более перспективным может стать исполь-зование специальных параболических линз [17]. Также возможно расположение фотодетектора рядом с кристаллом (см., например, [6]) и/или увеличение размера активного элемента, что, однако, приведет к увеличению размеров сенсора.…”

A Fiber-Coupled Scanning Magnetometer with Nitrogen-Vacancy Spins in a Diamond Nanobeam

“…Free-space optical access leads to additional heat load and increased complexity of cryostat design. A potential way to preclude the need for free-space optical access is to realize fiber-based scanning-NV sensors. , Here, we demonstrate a new scanning-NV sensor based on a tapered diamond nanobeam that is optically coupled to, and manipulated with, a tapered optical fiber. Such fiber-based NV nanobeam sensors could facilitate implementation in low-temperature setups, while benefiting from the potentially near-perfect optical coupling efficiency between fiber and nanobeam. − Moreover, nanobeams are excellently suited for nanophotonic structuring, , which could enable high-efficiency, resonant optical addressing of embedded NV centers or other group-IV color centers by incorporating photonic crystals.…”

“…A potential way to preclude the need for free-space optical access is to realize fiber-based scanning-NV sensors. 12,13 Here, we demonstrate a new scanning-NV sensor based on a tapered diamond nanobeam that is optically coupled to, and manipulated with, a tapered optical fiber. Such fiber-based NV nanobeam sensors could facilitate implementation in low-temperature setups, while benefiting from the potentially near-perfect optical coupling efficiency between fiber and nanobeam.…”