A microwave sensor determines an electric-field strength of a microwave field populated by quantum particles in an ultra-high vacuum (UHV) cell. A probe laser beam and a coupling laser beam are directed into the UHV cell so that they are generally orthogonal to each other and intersect to define a “Rydberg” intersection, so-called as the quantum particles within the Rydberg intersection transition to a pair of Rydberg states. The frequency of the probe laser beam is swept so that a frequency spectrum of the probe laser beam can be captured. The frequency spectrum is analyzed to determine a frequency difference between Autler-Townes peaks. The electric-field strength of the microwave field within the Rydberg intersection is then determined based on this frequency difference.

A microwave sensor determines an electric-field strength of a microwave field populated by quantum particles in an ultra-high vacuum (UHV) cell. A probe laser beam and a coupling laser beam are directed into the UHV cell so that they are generally orthogonal to each other and intersect to define a “Rydberg” intersection, so-called as the quantum particles within the Rydberg intersection transition to a pair of Rydberg states. The frequency of the probe laser beam is swept so that a frequency spectrum of the probe laser beam can be captured. The frequency spectrum is analyzed to determine a frequency difference between Autler-Townes peaks. The electric-field strength of the microwave field within the Rydberg intersection is then determined based on this frequency difference.

A magnetic measuring device includes: a determination part configured to identify four maximum inclination points in an average value in a visual field of a light detection magnetic resonance spectrum and configured to determined a degree of decrease in relative fluorescence intensity and a microwave frequency at each of the maximum inclination points; a setting part configured to set a reference decrease degree of the relative fluorescence intensity in a predetermined area and configured to set operating point frequency initial values at four points at which the reference decrease degree is achieved, near the microwave frequencies at the respective maximum inclination points; a frequency update part configured to update operating point frequencies at the four points; and a frequency correction part configured to input the updated operating point frequencies to a microwave oscillator as corrected operating point frequencies.

Certain aspects of the present disclosure provide methods and apparatus for closed-loop control of a system using one or more electron paramagnetic resonance (EPR) sensors located on-site. With such EPR sensors, a change can be applied to the system, the EPR sensors can measure the effect(s) of the change, and then adjustments can be made in real-time. This feedback process may be repeated continuously to control the system.

Certain aspects of the present disclosure provide methods and apparatus for closed-loop control of a system using one or more electron paramagnetic resonance (EPR) sensors located on-site. With such EPR sensors, a change can be applied to the system, the EPR sensors can measure the effect(s) of the change, and then adjustments can be made in real-time. This feedback process may be repeated continuously to control the system.

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.

A method of unambiguous identification and authentication of products for the purpose of better recognition of product forgeries and controlling product piracy, including applying to/into the product an identification substance admixture which contains paramagnetic phases or identifying a product which contains an identification substance admixture containing paramagnetic phases and has an ESR fingerprint spectrum that permits unambiguous identification of the product. Such an ESR fingerprint spectrum is easily measurable, but can be copied or forged only with difficulty. The method relates to an individualizable “femto tag” for femto ledgers and forms an important interface for what are known as “Internet of Things” (IOT).

A method of unambiguous identification and authentication of products for the purpose of better recognition of product forgeries and controlling product piracy, including applying to/into the product an identification substance admixture which contains paramagnetic phases or identifying a product which contains an identification substance admixture containing paramagnetic phases and has an ESR fingerprint spectrum that permits unambiguous identification of the product. Such an ESR fingerprint spectrum is easily measurable, but can be copied or forged only with difficulty. The method relates to an individualizable “femto tag” for femto ledgers and forms an important interface for what are known as “Internet of Things” (IOT).

A microwave sensor determines an electric-field strength of a microwave field populated by quantum particles in an ultra-high vacuum (UHV) cell. A probe laser beam and a coupling laser beam are directed into the UHV cell so that they are generally orthogonal to each other and intersect to define a “Rydberg” intersection, so-called as the quantum particles within the Rydberg intersection transition to a pair of Rydberg states. The frequency of the probe laser beam is swept so that a frequency spectrum of the probe laser beam can be captured. The frequency spectrum is analyzed to determine a frequency difference between Autler-Townes peaks. The electric-field strength of the microwave field within the Rydberg intersection is then determined based on this frequency difference.

A microwave sensor determines an electric-field strength of a microwave field populated by quantum particles in an ultra-high vacuum (UHV) cell. A probe laser beam and a coupling laser beam are directed into the UHV cell so that they are generally orthogonal to each other and intersect to define a “Rydberg” intersection, so-called as the quantum particles within the Rydberg intersection transition to a pair of Rydberg states. The frequency of the probe laser beam is swept so that a frequency spectrum of the probe laser beam can be captured. The frequency spectrum is analyzed to determine a frequency difference between Autler-Townes peaks. The electric-field strength of the microwave field within the Rydberg intersection is then determined based on this frequency difference.