Diamond-doped optical fibres for quantum sensing applications

Brant C. Gibson, M. Henderson, Heike Ebendorff‐Heidepriem +3 more

Henderson, Afshar, Greentree +1 more

Christian L. Degen

Dongbi Bai, Hoa Tran My Huynh, David Simpson +6 more

We demonstrate fabrication and characterizations of intrinsically magneto-sensitive fiber with potential applications as a high-efficiency remote magnetic field sensing platform. The fibre was fabricated using lead-silicate glass and the rod-intube fibre drawing technique. The thin glass rod of ~1 mm diameter was first coated with nitrogen-vacancy (NV) centreenriched diamond particles of ~1 μm diameter, and subsequently inserted into the glass outer tube. This rod-in-tube assembly was drawn down to fibre, with the diamond particles distributed at the fused interface between rod and tube. We experimentally coupled 532 nm continuous-wave laser into a 30-cm-length fibre piece from the fibre endface, and examined the photoluminescence (PL) properties of the fibre from both the side of the fibre and the output end of the fibre. PL mapping results showed that the glass-embedded NV emitters showed bright and photostable fluorescence, demonstrating characteristic NV centre zero phonon line emission. Moreover, the mapping result obtained at the output end of fibre indicated that the transmitted NV fluorescence was coupled into the propagation modes of the fibre. By using optically detected magnetic resonance (ODMR) from the NV ensemble along the fibre, we demonstrate detection of local magnetic fields via longitudinal excitation and side collection. Based on the current light transmission and collection configuration, the hybrid diamond-glass optical fibre sensor demonstrated a shot noise-limited DC magnetic field sensitivity of 3.7 μT/√Hz at room temperature. Our results open the possibility of robust, field-deployable fibre optical magnetometry.

Sean M. Blakley, Ilya V. Fedotov, Xinghua Liu +4 more

Matthew Green, Matthias Fabian, Tong Sheng Sun +1 more

Nitrogen-Vacancy (NV) centres in diamond have been shown to possess a quantised energy structure that allows for a number of macroscopic parameters to be measured with a high level of sensitivity. The process of sensing magnetic fields can be achieved through the behaviour of the NV centre’s electron spin triplet states using the separation of field-dependent and independent states, inferred by applying a microwave frequency to drive transitions. Observation of the states is achieved through optical pumping and stimulated emission, where the intensity of the fluorescent emission and frequency of the applied microwaves relates to the magnitude of the magnetic field the NV centre experiences. The optical method of sensing can be facilitated using optical fibres in which NV diamond particles are embedded between the core and outer fibre layers, leading to a robust platform for further practical applications with strong resistance to external interference.