Chopped Bias Magnetic Field Solid-State Spin Sensor For Low Frequency Measurements Of Physical Quantities

A method of measuring an external magnetic field with a solid-state host, the solid-state host comprising an ensemble of color center defects, each color center defect in the ensemble of color center defects having a corresponding resonance, the method comprising:

• applying a time-varying bias magnetic field to the ensemble of color center defects, the time-varying bias magnetic field splitting the resonances of the color center defects in the ensemble of color center defects;
• measuring shifts in the resonances of the color center defects caused by the external magnetic field and the time-varying bias magnetic field;
• and
• determining a magnitude and/or direction of the external magnetic field based on the shifts in the resonances of the color center defects and the time-varying bias magnetic field.

A magnetic field sensor comprising:

• a solid-state host containing color center defects having respective resonances, the respective resonances shifting in response to an external magnetic field;
• a magnetic field source, in electromagnetic communication with the color center defects, to apply a time-varying bias magnetic field to the color center defects, the time-varying bias magnetic field splitting the respective resonances of the color center defects;
• at least one radiation source, in electromagnetic communication with the color center defects, to irradiate the color center defects with radiation;
• a detector, in electromagnetic communication with the color center defects, to detect a spectroscopic signature of the color center defects in response to the radiation;
• and
• a processor, operably coupled to the detector, to determine an amplitude and/or direction of the external magnetic field based on the time-varying bias magnetic field and the spectroscopic signature of the color center defects.