Patents by Inventor Thad G. Walker

Thad G. Walker has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20240019476
    Abstract: One example includes an electrometer system. The system includes a sensor cell comprising an alkali metal vapor within. The system also includes an excitation beam system configured to provide at least one excitation optical beam through the sensor cell to excite the alkali metal atoms from a ground state to a Rydberg energy state. The system also includes a stimulated emission beam system configured to provide a stimulated emission optical beam through the sensor cell to provide energy decay of the alkali metal atoms to a decay energy state that is less than the Rydberg energy state. The system further includes a detection system configured to monitor fluorescent detection light emitted from the alkali metal atoms as the alkali metal atoms decay from the decay state to the ground state to determine signal characteristics of an external signal based on an intensity of the fluorescent detection light.
    Type: Application
    Filed: July 10, 2023
    Publication date: January 18, 2024
    Inventors: ERIC A. IMHOF, STEVEN RYAN JEFFERTS, THAD G. WALKER, VYACHESLAV LEBEDEV
  • Patent number: 11726123
    Abstract: 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.
    Type: Grant
    Filed: December 16, 2021
    Date of Patent: August 15, 2023
    Assignee: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: Thad G. Walker, Eric A. Imhof, Steven Ryan Jefferts
  • Patent number: 11674992
    Abstract: 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.
    Type: Grant
    Filed: December 16, 2021
    Date of Patent: June 13, 2023
    Assignee: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: Thad G. Walker, Eric A. Imhof, Steven Ryan Jefferts
  • Publication number: 20220196719
    Abstract: 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.
    Type: Application
    Filed: December 16, 2021
    Publication date: June 23, 2022
    Applicant: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: THAD G. WALKER, ERIC A. IMHOF, STEVEN RYAN JEFFERTS
  • Publication number: 20220196718
    Abstract: 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.
    Type: Application
    Filed: December 16, 2021
    Publication date: June 23, 2022
    Applicant: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: THAD G. WALKER, ERIC A. IMHOF, STEVEN RYAN JEFFERTS
  • Patent number: 11294005
    Abstract: 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.
    Type: Grant
    Filed: July 14, 2020
    Date of Patent: April 5, 2022
    Assignee: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: Thad G. Walker, Michael D. Bulatowicz
  • Publication number: 20220018913
    Abstract: 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.
    Type: Application
    Filed: July 14, 2020
    Publication date: January 20, 2022
    Applicant: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: THAD G. WALKER, MICHAEL D. BULATOWICZ
  • Patent number: 11133117
    Abstract: 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.
    Type: Grant
    Filed: May 5, 2020
    Date of Patent: September 28, 2021
    Assignee: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: Michael S. Larsen, Thad G. Walker, Justin M. Brown
  • Publication number: 20200357534
    Abstract: 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.
    Type: Application
    Filed: May 5, 2020
    Publication date: November 12, 2020
    Applicant: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: MICHAEL S. LARSEN, THAD G. WALKER, JUSTIN M. BROWN
  • Patent number: 10823790
    Abstract: 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.
    Type: Grant
    Filed: August 2, 2018
    Date of Patent: November 3, 2020
    Assignee: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: Michael D. Bulatowicz, Thad G. Walker, Michael S. Larsen
  • Patent number: 10782368
    Abstract: 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.
    Type: Grant
    Filed: May 29, 2018
    Date of Patent: September 22, 2020
    Assignee: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: Michael D. Bulatowicz, Thad G. Walker, Michael S. Larsen
  • Patent number: 10725431
    Abstract: 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.
    Type: Grant
    Filed: December 12, 2019
    Date of Patent: July 28, 2020
    Assignee: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: Michael S. Larsen, Thad G. Walker
  • Publication number: 20200117146
    Abstract: 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.
    Type: Application
    Filed: December 12, 2019
    Publication date: April 16, 2020
    Applicant: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: MICHAEL S. LARSEN, THAD G. WALKER
  • Patent number: 10539929
    Abstract: 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.
    Type: Grant
    Filed: October 2, 2017
    Date of Patent: January 21, 2020
    Assignee: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: Michael S. Larsen, Thad G. Walker
  • Publication number: 20180372813
    Abstract: 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.
    Type: Application
    Filed: August 2, 2018
    Publication date: December 27, 2018
    Applicant: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: MICHAEL D. BULATOWICZ, THAD G. WALKER, MICHAEL S. LARSEN
  • Publication number: 20180348313
    Abstract: 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.
    Type: Application
    Filed: May 29, 2018
    Publication date: December 6, 2018
    Applicant: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: MICHAEL D. BULATOWICZ, THAD G. WALKER, MICHAEL S. LARSEN
  • Patent number: 9970999
    Abstract: 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.
    Type: Grant
    Filed: May 31, 2013
    Date of Patent: May 15, 2018
    Assignee: Northrop Grumman Systems Corporation
    Inventors: Michael S. Larsen, Henry C. Abbink, Thad G. Walker, Michael D. Bulatowicz
  • Publication number: 20180101139
    Abstract: 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.
    Type: Application
    Filed: October 2, 2017
    Publication date: April 12, 2018
    Applicant: NORTHROP GRUMMAN SYSTEMS CORPORATION
    Inventors: MICHAEL S. LARSEN, THAD G. WALKER
  • Patent number: 9234912
    Abstract: 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.
    Type: Grant
    Filed: May 31, 2013
    Date of Patent: January 12, 2016
    Assignee: Northrop Grumman Systems Corporation
    Inventors: Thad G. Walker, Michael S. Larsen
  • Patent number: 9229073
    Abstract: 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.
    Type: Grant
    Filed: December 27, 2012
    Date of Patent: January 5, 2016
    Assignee: Northrop Grumman Guidance and Electronics Company, Inc.
    Inventors: Thad G. Walker, Michael D. Bulatowicz, Michael S. Larsen, Robert C. Griffith, Philip R. Clark