Systems and methods of quantum sensing include depositing a sample volume onto an ensemble of quantum defects, hyperpolarizing spins in the sample volume, performing a sensing sequence, and reading out information regarding electronic spin states of the quantum defects in the ensemble of quantum defects, which sense the hyperpolarized spins in the sample volume.

A magnetometer includes an electron spin defect body including a plurality of lattice point defects. A microwave field transmitter is operable to apply a microwave field to the electron spin defect body. An optical source is configured to emit input light of a first wavelength that excites the plurality of lattice point defects of the electron spin defect body from a ground state to an excited state. A first optical fiber has an input end optically coupled to the optical source and an output end. The output end is attached to a first face of the electron spin defect body and is arranged to direct the input light into the first face of the electron spin defect body. A second optical fiber has an output end and an input end. A photodetector is optically coupled to the output end of the second optical fiber.

An atomic magnetometer system is disclosed that includes a variable magnetic field source (14) configured to provide an oscillating primary magnetic field to cause a sample (16) to produce a secondary magnetic field. The atomic magnetometer system also includes an atomic magnetometer for detecting the secondary magnetic field. The atomic magnetometer includes an atomic specimen, a pump and probe subsystem configured to pump the atomic specimen to create a polarisation and to probe atomic coherence precession within the atomic specimen with a probe beam, a detector configured to detect the probe beam to produce a detection signal. The system is configured to drive the variable magnetic field source (14) in dependence on the detection signal with a frequency tuned to rf resonance. A method of operating an atomic magnetometer is also disclosed.

An apparatus for individually trapping atoms, individually imaging the atoms, and individually cooling the atoms to prevent loss of the atoms from the trap caused by the imaging. The apparatus can be implemented in various quantum computing, sensing, and metrology applications (e.g., in an atomic clock).

A magnetometer includes a vapor cell having at least one wall, a chamber defined by the at least one wall, and alkali metal atoms disposed in the chamber to produce an alkali metal vapor in the chamber, wherein the at least one wall includes an oxide-containing interior surface; and an anti-relaxation coating disposed on the oxide-containing interior surface of the at least one wall of the vapor cell, wherein the anti-relaxation coating is a reaction product of the oxide-containing interior surface of the at least one wall with at least one mono- or dichlorosilane compound.

A magnetometer includes a sample signal device; a reference signal device; a microwave field generator operable to apply a microwave field to the sample signal device and the reference signal device; an optical source configured to emit light including light of a first wavelength that interacts optically with the sample signal device and with the reference signal device; at least one photodetector arranged to detect a sample photoluminescence signal including light of a second wavelength emitted from the sample signal device and a reference photoluminescence signal including light of the second wavelength emitted from the reference signal device, in which the first wavelength is different from the second wavelength; and a magnet arranged adjacent to the sample signal device and the reference signal device.

Disclosed herein is a method of detecting a material response. The method includes providing an oscillating primary magnetic field to cause a sample to produce a secondary magnetic field. The method also includes reducing the effect on an atomic magnetometer of components of the primary and secondary magnetic fields in a direction substantially orthogonal to a surface of the sample. The method also includes detecting the secondary magnetic field with the atomic magnetometer to detect the material response.

Microwave resonator readout of the cavity-spin interaction between a spin defect center ensemble and a microwave resonator yields fidelities that are orders of magnitude higher than is possible with optical readouts. In microwave resonator readout, microwave photons probe a microwave resonator coupled to a spin defect center ensemble subjected to a physical parameter to be measured. The physical parameter shifts the spin defect centers' resonances, which in turn change the dispersion and/or absorption of the microwave resonator. The microwave photons probe these dispersion and/or absorption changes, yielding a measurement with higher visibility, lower shot noise, better sensitivity, and higher signal-to-noise ratio than a comparable fluorescence measurement. In addition, microwave resonator readout enables coherent averaging of spin defect center ensembles and is compatible with spin systems other than nitrogen vacancies in diamond.

One embodiment is a magnetic field measurement system that includes at least one magnetometer having a vapor cell, a light source to direct light through the vapor cell, and a detector to receive light directed through the vapor cell; at least one magnetic field generator disposed adjacent the vapor cell; and a feedback circuit coupled to the at least one magnetic field generator and the detector of the at least one magnetometer. The feedback circuit includes at least one feedback loop that includes a first low pass filter with a first cutoff frequency. The feedback circuit is configured to compensate for magnetic field variations having a frequency lower than the first cutoff frequency. The first low pass filter rejects magnetic field variations having a frequency higher than the first cutoff frequency and provides the rejected magnetic field variations for measurement as an output of the feedback circuit.

A cell for a optically pumped magnetic sensor measures magnetic field by setting alkali metal atoms to a predetermined excitation state by a pump beam and detecting the excitation state by a probe beam. The cell is provided with a glass substrate which seals the alkali metal atoms and an enclosing gas and transmits the pump beam and the probe beam and a coating layer provided on an inner surface of the glass substrate. The coating layer is made of an inorganic material.