# US 10,371,766 B2 · Systems and methods for improving the functionality of optically pumped magnetometer in self-oscillating mode > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,371,766 B2 - Document ID: US10371766B2 - Status: Granted - Kind: B2 - Application number: 15/525,554 - Filed: 2015-11-09 - Published: 2018-10-11 - Granted: 2019-08-06 - Earliest claimed: 2014-11-10 - Assignees: Geotech Ltd. - Applicants: Geotech Ltd. - Inventors: Ryan S. Raz - Web page: https://patentgrep.com/patent/US10371766B2 ## CPC - G01R 33/26: using optical pumping - G01V 3/16: specially adapted for use from aircraft (G01V3/165 - G01V3/175 take precedence) - G01V 3/165: operating with magnetic or electric fields produced or modified by the object or by the detecting device (with electromagnetic waves G01V3/17) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) ## Abstract A method and system that includes injecting light into a vapor cell; detecting an output of the light from the vapor cell; modulating the light injected into the vapor cell in dependence on the detected output to achieve an oscillating signal; applying an energy pulse to the vapor cell prior to achieving the oscillating signal to decrease a time required to achieve the oscillating signal; and determining a magnetic field measurement in dependence on a frequency of the oscillating signal. ## Claims ### Claim 1 A method for a self-oscillating magnetometer, comprising: injecting light into a vapor cell; detecting an output of the light from the vapor cell; modulating the light injected into the vapor cell in dependence on the detected output to achieve an oscillating signal; applying an energy pulse to the vapor cell prior to achieving the oscillating signal to cause self-oscillation to begin within a duration that corresponds to one cycle of the oscillating signal; and determining a magnetic field measurement in dependence on a frequency of the oscillating signal. ### Claim 2 (depends on 1) The method of claim 1 wherein the energy pulse has a duration that is less than an anticipated duration of one cycle of the oscillating signal. ### Claim 3 (depends on 1) The method of claim 1 wherein the energy pulse has a duration that is less than one half of an anticipated duration of one cycle of the oscillating signal. ### Claim 4 (depends on 1) The method of claim 1 wherein the energy pulse has a broad band power spectrum that covers all possible operating frequencies of the oscillating signal. ### Claim 5 (depends on 1) The method of claim 1 wherein modulating the light comprises applying an RF signal through an electrical coil to the vapor cell at a Larmor frequency. ### Claim 6 (depends on 5) The method of claim 5 wherein applying the energy pulse to the vapor cell comprises applying the energy pulse through a further electrical coil to the vapor cell. ### Claim 7 (depends on 5) The method of claim 5 wherein applying the energy pulse to the vapor cell comprises applying the energy pulse through the same electrical coil as the RF signal. ### Claim 8 (depends on 1) The method of claim 1 wherein modulating the light comprises applying an optical signal using a light source to the vapor cell at a Larmor frequency. ### Claim 9 (depends on 8) The method of claim 8 wherein applying the energy pulse to the vapor cell comprises applying the energy pulse through the light source or a further light source to the vapor cell. ### Claim 10 (depends on 8) The method of claim 8 wherein applying the energy pulse to the vapor cell comprising applying the energy pulse through an electrical coil to the vapor cell. ### Claim 11 (depends on 1) The method of claim 1 wherein the injecting, detecting, modulating, applying and determining are all implemented by magnetometer system that is supported by an aircraft, wherein applying the energy pulse is triggered by detecting when a periodic EM signal has entered an off state. ### Claim 12 A self-oscillating magnetometer apparatus comprising: a vapor cell containing an alkali vapor a light source for injecting light into the vapor cell; a detector for detecting an output of the light from the vapor cell; a modulating device for modulating the light injected into the vapor cell in dependence on the detected output to achieve an oscillating signal; and a driver for applying an energy pulse to the vapor cell prior to achieving the oscillating signal to cause self-oscillation to begin within a duration that corresponds to one cycle of the oscillating signal; wherein a magnetic field measurement is represented by a frequency of the oscillating signal. ### Claim 13 (depends on 12) The apparatus of claim 12 wherein the energy pulse has a duration that is less than an anticipated duration of one cycle of the oscillating signal. ### Claim 14 (depends on 12) The apparatus of claim 12 wherein the energy pulse has a duration that is less than one half of an anticipated duration of one cycle of the oscillating signal. ### Claim 15 (depends on 12) The apparatus of claim 12 wherein the energy pulse has a broad band power spectrum that covers all possible operating frequencies of the oscillating signal. ### Claim 16 (depends on 12) The apparatus of claim 12 comprising an electrical coil that is connected to the driver for applying the energy pulse to the vapor cell as an RF signal. ### Claim 17 (depends on 16) The apparatus of claim 16 wherein the electrical coil is part of the modulating device. ### Claim 18 (depends on 16) The apparatus of claim 16 wherein the modulating device comprises a further electrical coil for applying a depolarizing signal to the vapor cell. ### Claim 19 (depends on 16) The apparatus of claim 16 wherein the modulating device comprises a further light source for applying a depolarizing signal to the vapor cell. ### Claim 20 (depends on 12) The apparatus of claim 12 comprising a further light source that is connected to the driver for applying the energy pulse to the vapor cell as a light signal. ### Claim 21 (depends on 12) The apparatus of claim 12 wherein the light source is part of the modulating device. ### Claim 22 (depends on 12) The apparatus of claim 12 including: an airborne surveying system that comprises a transmitter coil for generating a periodic EM signal having an on state and off state; a switch that causes the driver to apply the energy pulse after the periodic EM signal enters an off state.