Northrop Grumman Systems Corporation

Wisconsin Alumni Research Foundation

Northrop Grumman Guidance and Electronics Company, Inc.

Thad Gilbert Walker

Michael S Larsen

Michael D Bulatowicz

Eric A Imhof

Steven Ryan Jefferts

Ian A Nelson

Brian Robert Lancor

Robert Wyllie

Bien Chann

Henry C Abbink

Robert C Griffith

Philip R Clark

Justin M Brown

One embodiment includes an electrometer system. The system includes a sensor cell comprising alkali metal atoms within, and a probe laser configured to generate a probe beam, the probe beam being provided through the sensor cell. The system also includes a coupling laser configured to generate a coupling beam. The coupling beam can be provided through the sensor cell to combine with the probe beam provided through the sensor cell to provide a Rydberg energy state of the alkali metal atoms, the probe beam exiting the sensor cell as a detection beam. The system further includes a sensor control system configured to monitor the detection beam to detect an external signal based on monitoring a phase of the detection beam.

Electrometer sensor control system

One embodiment includes an electrometer system. The system includes a sensor cell comprising alkali metal atoms within, and an optical beam system configured to provide at least one optical beam through the sensor cell to provide a first Rydberg energy state of the alkali metal atoms, the at least one optical beam exiting the sensor cell as a detection beam. The system also includes a tuning signal generator configured to generate a tuning signal having a predetermined tuning frequency to adjust an energy difference between the first Rydberg energy state and a second Rydberg energy state of the alkali metal atoms. The system further includes a detection system configured to monitor the detection beam to detect an external signal having a frequency that is approximately equal to the energy difference between the first Rydberg energy state and the second Rydberg energy state based on monitoring the detection beam.

Electrometer with Rydberg frequency tuning

One example includes a magnetometer that includes a sensor cell comprising alkali metal vapor and a magnetic field generator system that generates predetermined AC magnetic fields through the sensor cell. The magnetometer also includes a laser system to provide optical pump and probe beams through the sensor cell in a pulsed manner to facilitate precession of the alkali metal vapor and to provide a detection beam corresponding to the optical probe beam exiting the sensor cell. The detection beam exhibits an optical property corresponding to a modified precession of the alkali metal vapor based on the predetermined AC magnetic fields and an external magnetic field. The magnetometer also includes a detection system to monitor the detection beam to detect the modified precession of the alkali metal vapor to calculate scalar and vector components of the external magnetic field based on the plurality of predetermined AC magnetic fields.

Synchronous light-pulse atomic magnetometer system

An atom interferometer system includes a sensor cell comprising alkali metal atoms. An optical system generates first and second interrogation beams having respective first and second frequencies and a circular polarization. The optical system includes optics that provide the first and second interrogation beams through the sensor cell in a first direction and reflect the first and second interrogation beams back through the sensor cell in a second direction opposite the first direction and in a same circular polarization to drive the alkali metal atoms from a first energy state to a greater energy state during an interrogation stage of sequential measurement cycles. A detection system detects a state distribution of a population of the alkali metal atoms between the first energy state and the second energy state during the interrogation stage based on an optical response.

Atomic interferometer system

One example includes a magnetometer system that includes a sensor cell comprising alkali metal vapor and at least one measurement zone corresponding to a three-dimensional spatial region within the sensor cell. The system also includes a laser system configured to provide an optical pump beam through the sensor cell in a pulsed manner to facilitate precession of the alkali metal vapor in response to an external magnetic field and to provide an optical probe beam through the sensor cell in a pulsed manner based on a precession frequency of the alkali metal vapor. The system also includes a detection system configured to detect the precession of the alkali metal vapor in response to a detection beam corresponding to the optical probe beam exiting the sensor cell and to calculate an amplitude and direction of the external magnetic field based on the detected precession of the alkali metal vapor.

Pulsed-beam atomic magnetometer system

One example includes a magnetometer system. The system includes a sensor cell comprising alkali metal vapor and a laser system configured to provide an optical pump beam through the sensor cell in a pulsed manner to facilitate precession of the alkali metal vapor in response to an external magnetic field and to provide an optical probe beam through the sensor cell in a pulsed manner based on a precession frequency of the alkali metal vapor. The system also includes a detection system configured to detect the precession of the alkali metal vapor in response to a detection beam corresponding to the optical probe beam exiting the sensor cell and to calculate an amplitude and direction of the external magnetic field based on the detected precession of the alkali metal vapor.

An atomic clock system includes a magneto-optical trap (MOT) system that traps alkali metal atoms in a cell during a trapping stage of each of sequential coherent population trapping (CPT) cycles. The system also includes an interrogation system that generates an optical difference beam comprising a first optical beam having a first frequency and a second optical beam having a second frequency different from the first frequency. The interrogation system includes a direction controller that periodically alternates a direction of the optical difference beam through the cell during a CPT interrogation stage of each of the sequential clock measurement cycles to drive CPT interrogation of the trapped alkali metal atoms. The system also includes an oscillator system that adjusts a frequency of a local oscillator based on an optical response of the CPT interrogated alkali metal atoms during a state readout stage in each of the sequential clock measurement cycles.

Atomic clock system

One embodiment includes a nuclear magnetic resonance (NMR) sensor system. The system includes a pump laser configured to generate an optical pump beam at a first wavelength and a probe laser configured to generate an optical probe beam at a second wavelength that is different from the first wavelength. The system also includes beam optics configured to direct the pump laser and the probe laser along orthogonal axes through a sensor cell comprising an alkali metal vapor. The system further includes detection optics that include a photodetector assembly configured to measure at least one characteristic associated with the optical probe beam leaving the sensor cell for measurement of a polarization vector of the alkali metal vapor. The detection optics can include at least one filter configured to filter light having the first wavelength and to pass light having the second wavelength to the photodetector assembly.

Nuclear magnetic resonance probe system

Measurement of a precessional rate of a gas, such as an alkali gas, in a magnetic field is made by promoting a non-uniform precession of the gas in which substantially no net magnetic field affects the gas during a majority of the precession cycle. This allows sensitive gases that would be subject to spin-exchange collision de-phasing to be effectively used for extremely sensitive measurements in the presence of an environmental magnetic field such as the Earth's magnetic field.

Gas magnetometer

One embodiment includes an accelerometer system. The accelerometer system can include a Far-Off Resonance Trap (FORT) control system configured to generate an optical trapping beam. The system can also include a FORT accelerometer detection system including a FORT that is configured to trap a cluster of atoms based on the optical trapping beam. The FORT accelerometer detection system can also include an interrogation system configured to determine motion of the cluster of atoms along at least one axis resulting from an external acceleration in the at least one axis based on a relative phase shift of an optical probe beam through the cluster of atoms. The system can further include an acceleration processor configured to calculate the external acceleration in the at least one axis based on the relative phase shift of the optical probe beam.

Atomic far-off resonance trap (FORT) accelerometer system

One embodiment includes a sensor system. The system includes a cell system comprising a pump laser configured to generate a pump beam to polarize alkali metal particles enclosed within a sensor cell. The system also includes a detection system comprising a probe laser configured to generate a probe beam. The detection system can also be configured to calculate at least one measurable parameter based on characteristics of the probe beam passing through the sensor cell resulting from precession of the polarized alkali metal particles in response to an applied magnetic field. The system further includes an AC Stark shift control system configured to frequency-modulate the pump beam and to control a center frequency of a frequency-modulated pump beam based on the characteristics of the probe beam passing through the sensor cell to substantially stabilize and mitigate the effects of AC Stark shift on the at least one measurable parameter.

Systems and method to substantially mitigate AC stark shift effects in a sensor system

Precise measurements of a precessional rate of noble gas in a magnetic field is obtained by constraining the time averaged direction of the spins of a stimulating alkali gas to lie in a plane transverse to the magnetic field. In this way, the magnetic field of the alkali gas does not provide a net contribution to the precessional rate of the noble gas.

Noble gas magnetic resonator

A high power diode laser system utilizes an external cavity to narrow the spectral width of a high power multimode diode laser to change the output power normally produced by the diode from a broad spectrum to a very narrow spectrum. The power output of the laser system is concentrated over a narrow spectral range which falls within the useable range for particular applications, such as optical pumping of noble gas samples for magnetic resonance imaging. The output of the diode is received by a collimating element which directs the light on a beam path to a diffraction grating which is oriented at an angle to the incident beam. A portion of the beam may be directed from the diffraction grating to provide useable output light, and a portion of the light incident on the grating is directed back to be focused on the diode to provide feedback to cause the diode to preferentially lase at the wavelength of the light that is fed back. A polarization rotation element may be used to orient the polarization of the light passing through it to control the amount of feedback light.

Frequency-narrowed high power diode laser system with external cavity

A high power diode laser array system utilizes an external cavity to narrow the spectral width of a high power diode laser array to change the output power normally produced by the diode array from a broad spectrum to a very narrow spectrum. The power output of the laser array system is concentrated over a narrow spectral range which falls within the useable range for particular applications such as optical pumping of noble gas samples for magnetic resonance imaging. The output of the array is received by a collimating element, which collimates the light in a direction perpendicular to the direction of the length of the array of emitters and directs the light on a beam path to a diffraction grating which is oriented at an angle to the incident beam. A portion of the beam is directed from the diffraction grating to provide useable output light, and a portion of the light incident on the grating is directed back to be focused on the diode array to provide feedback to cause the diode array to preferentially lase at the wavelength of the light that is fed back. A polarization rotation element may be used to orient the polarization of the light passing through it to control the amount of feedback light.

Growing community of inventors

Madison, WI, United States of America

Thad Gilbert Walker