Abstract: A mental state awareness system comprises a non-invasive brain interface assembly configured for detecting brain activity of a user, a processor configured for determining a mental state of a user based on the detected brain activity, and a biofeedback device configured for automatically providing biofeedback to the user indicative of the determined mental state of the user.

Abstract: An active shield magnetometry system comprises at least one magnetic field actuator configured for generating an actuated magnetic field that at least partially cancels an outside magnetic field, thereby yielding a total residual magnetic field. The active shield magnetometry system further comprises a plurality of magnetometers respectively configured for measuring the total residual magnetic field and outputting a plurality of total residual magnetic field measurements. The active shield magnetometry system further comprises at least one feedback control loop comprising at least one optimal linear controller configured for controlling the actuated magnetic field at least partially based on at least one of the plurality of total residual magnetic field measurements respectively output by at least one of the plurality of magnetometers.

Abstract: At least one magnetic field actuator is configured for generating an actuated magnetic field that at least partially cancels an outside magnetic field, thereby yielding a total residual magnetic field. A plurality of magnetometers are configured for taking measurements of the total residual magnetic field. The magnetometers include a plurality of coarse magnetometers and a plurality of fine magnetometers. A processor is configured for acquiring the total residual magnetic field measurements from the coarse magnetometers, estimating the total residual magnetic field at the fine magnetometers based on total residual magnetic field measurements acquired from the plurality of coarse magnetometers, and controlling the actuated magnetic field at least partially based on the total residual magnetic field estimates at the fine magnetometers in a manner that suppresses the total residual magnetic field at the fine magnetometers to a baseline level, such that at least one of the fine magnetometers is in-range.

Abstract: A calibration system for a magnetometer having an unknown gain is disclosed. A calibration magnetic field is generated at a calibration frequency of a known amplitude at the magnetometer. A measurement of the calibrating magnetic field is reported by the magnetometer. A ratio of an amplitude of the calibration magnetic field measurement reported by the magnetometer and the known amplitude of the calibrating magnetic field at the magnetometer is computed. The unknown gain of the magnetometer is determined at least partially based on computed ratio.

Abstract: An actuated magnetic field is generated at a plurality of distinct frequencies that at least partially cancels an outside magnetic field at the plurality of distinct frequencies, thereby yielding a total residual magnetic field. The total residual magnetic field is coarsely detected and a plurality of coarse error signals are respectively output. The total residual magnetic field is finely detected and a plurality of fine error signals are respectively output. The actuated magnetic field is controlled respectively at the plurality of distinct frequencies at least partially based on at least one of the plurality of coarse error signals, and finely controlled respectively at the plurality of distinct frequencies at least partially based on at least one of the plurality of fine error signals.

Abstract: Measurements of an arbitrary magnetic field having one or more magnetic field components are acquired from a plurality of magnetometers, and a generic model of at least one of the one or more magnetic field components of the arbitrary magnetic field is generated in the vicinity of the magnetometers. The generic magnetic field model comprises an initial number of different basis functions. Maxwell's equations are applied to the generic magnetic field model to reduce the initial number of different basis functions, thereby yielding a Maxwell-constrained model of the magnetic field component(s) of the arbitrary magnetic field, and the magnetic field component(s) of the arbitrary magnetic field are estimated at each of at least one of the magnetometers based on the constrained magnetic field model and the arbitrary magnetic field measurements acquired from each magnetometer.

Abstract: 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.

Abstract: 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.

Abstract: A magnetic field measurement system includes at least one magnetometer; and at least one flux concentrator made of a high magnetic permeability material and configured to receive magnetic field signals from a source, to concentrate the magnetic field signals or reorient the magnetic field signals in a preselected direction, and to direct the concentrated or reoriented magnetic field signals toward at least one of the at least one magnetometer. In addition to, or as an alternative to, the flux concentrator, the system can include a passive shield made of the high magnetic permeability material. The system may also include active shielding.

Abstract: A magnetic field measurement system includes an array of magnetometers; at least one magnetic field generator configured to generate a compensation field across the array of magnetometers; and a controller coupled to the magnetometers and the at least one magnetic field generator and configured for adjusting a dynamic range and sensitivity of the array by adjusting a spatial variation of the compensation field to alter which of the magnetometers of the array operate in a measurement mode. Another magnetic field measurement system utilizes at least one magnetometer instead of the array. The controller is configured for adjusting a dynamic range and sensitivity of the array by adjusting a spatial variation of the compensation field to alter which of multiple domains within the at least one magnetometer operate in the measurement mode.

Abstract: A magnetic field measurement system that includes at least one magnetometer; at least one magnetic field generator; a processor coupled to the at least one magnetometer and the at least one magnetic field generator and configured to: measure an ambient background magnetic field using at least one of the at least one magnetometer in a first mode selected from a scalar mode or a vector mode; generate, in response to the measurement of the ambient background magnetic field, a compensation field using the at least one magnetic field generator; and measure a target magnetic field using at least one of the at least one magnetometer in a spin exchange relaxation free (SERF) mode which is different from the first mode.

Abstract: A magnetic field measurement system that includes at least one magnetometer; at least one magnetic field generator; a processor coupled to the at least one magnetometer and the at least one magnetic field generator and configured to: measure an ambient background magnetic field using at least one of the at least one magnetometer in a first mode selected from a scalar mode or a vector mode; generate, in response to the measurement of the ambient background magnetic field, a compensation field using the at least one magnetic field generator; and measure a target magnetic field using at least one of the at least one magnetometer in a spin exchange relaxation free (SERF) mode which is different from the first mode.

Abstract: An optically pumped magnetometer includes a vapor cell; at least one light source configured to produce a pump light beam and a probe light beam; a lens disposed between the at least one light source and the vapor cell; a quarter wave plate disposed between the lens and the vapor cell; a mirror configured to receive the pump light beam and probe light beam after passing through the vapor cell and reflect the pump light beam and probe light beam back through the vapor cell, the quarter wave plate, and the lens; and at least one detector configured to receive the probe light beam reflected by the mirror.

Abstract: 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.

Abstract: A magnetic field measurement system that includes at least one magnetometer; at least one magnetic field generator; a processor coupled to the at least one magnetometer and the at least one magnetic field generator and configured to: measure an ambient background magnetic field using at least one of the at least one magnetometer in a first mode selected from a scalar mode or a vector mode; generate, in response to the measurement of the ambient background magnetic field, a compensation field using the at least one magnetic field generator; and measure a target magnetic field using at least one of the at least one magnetometer in a spin exchange relaxation free (SERF) mode which is different from the first mode.

Abstract: A magnetic field measurement system that includes at least one magnetometer; at least one magnetic field generator; a processor coupled to the at least one magnetometer and the at least one magnetic field generator and configured to: measure an ambient background magnetic field using at least one of the at least one magnetometer in a first mode selected from a scalar mode or a vector mode; generate, in response to the measurement of the ambient background magnetic field, a compensation field using the at least one magnetic field generator; and measure a target magnetic field using at least one of the at least one magnetometer in a spin exchange relaxation free (SERF) mode which is different from the first mode.

Abstract: A magnetic field measurement system that includes at least one magnetometer; at least one magnetic field generator; a processor coupled to the at least one magnetometer and the at least one magnetic field generator and configured to: measure an ambient background magnetic field using at least one of the at least one magnetometer in a first mode selected from a scalar mode or a vector mode; generate, in response to the measurement of the ambient background magnetic field, a compensation field using the at least one magnetic field generator; and measure a target magnetic field using at least one of the at least one magnetometer in a spin exchange relaxation free (SERF) mode which is different from the first mode.

Abstract: A magnetic field measurement system includes at least one magnetometer; and at least one flux concentrator made of a high magnetic permeability material and configured to receive magnetic field signals from a source, to concentrate the magnetic field signals or reorient the magnetic field signals in a preselected direction, and to direct the concentrated or reoriented magnetic field signals toward at least one of the at least one magnetometer. In addition to, or as an alternative to, the flux concentrator, the system can include a passive shield made of the high magnetic permeability material. The system may also include active shielding.

Abstract: A magnetometer can include a single, integrated, unitary structure that has a gas cell defining a cavity having a vapor or vaporizable material disposed therein, a collimating element coupled to the gas cell and configured for collimating light directed toward the gas cell, and a lens element coupled the gas cell and configured for redirecting at least a portion of light that has passed through the gas cell. Additionally or alternatively, a gas cell of a magnetometer may be made of sapphire.

Abstract: A magnetic field measurement system includes an array of magnetometers; at least one magnetic field generator configured to generate a compensation field across the array of magnetometers; and a controller coupled to the magnetometers and the at least one magnetic field generator and configured for adjusting a dynamic range and sensitivity of the array by adjusting a spatial variation of the compensation field to alter which of the magnetometers of the array operate in a measurement mode. Another magnetic field measurement system utilizes at least one magnetometer instead of the array.