Device and methodology for measuring minute changes in ambient magnetic field

Abstract

An optical magnetometer comprising: a response frequency measurement unit comprising a vapor cell, a pulsed-mode pump laser and a probe laser; and a computing unit configured to compute a magnetic field change based on a difference between at least two temporally-distinct response frequency values received from the frequency measurement unit. Optionally, the response frequency measurement unit is magnetically non-shielded.

What is claimed is: 
     
         1 . An optical magnetometer comprising:
 a response frequency measurement unit comprising a vapor cell, a pulsed-mode pump laser and a probe laser; and   a computing unit configured to compute a magnetic field change based on a difference between at least two temporally-distinct response frequency values received from the response frequency measurement unit;   wherein said response frequency measurement unit is magnetically non-shielded.   
     
     
         2 . The optical magnetometer according to  claim 1 , wherein said vapor cell comprises alkaline atoms. 
     
     
         3 . The optical magnetometer according to  claim 2 , wherein said alkaline atoms are selected from the group consisting of Cesium (Cs), Rubidium (Rb) and Potassium (K). 
     
     
         4 . The optical magnetometer according to  claim 2 , wherein said response frequency measurement unit further comprises an oven configured to control a temperature in said vapor cell. 
     
     
         5 . The optical magnetometer according to  claim 1 , wherein said pump laser comprises a pulse diode laser configured to emit a pulsating laser beam. 
     
     
         6 . The optical magnetometer according to  claim 5 , wherein said pump laser further comprises a diffraction grating configured to tune the pulsating laser beam. 
     
     
         7 . The optical magnetometer according to  claim 6 , wherein said response frequency measurement unit further comprises an optical delivery system and a polarimeter system. 
     
     
         8 . The optical magnetometer according to  claim 7 , wherein said pump laser further comprises a linear polarizer configured to filter the pulsating laser beam. 
     
     
         9 . The optical magnetometer according to  claim 5 , wherein said pump laser further comprises a circular polarizer configured to circularly polarize the pulsating laser beam. 
     
     
         10 . The optical magnetometer according to  claim 9 , wherein said circular polarizer is a λ/4 quarter wave plate. 
     
     
         11 . The optical magnetometer according to  claim 1 , wherein said probe laser comprises a single mode diode laser. 
     
     
         12 . The optical magnetometer according to  claim 11 , wherein said probe laser further comprises a linear polarizer. 
     
     
         13 . The optical magnetometer according to  claim 1 , wherein said response frequency measurement unit further comprises a polarized splitter configured to split a beam transmitted by said probe laser. 
     
     
         14 . The optical magnetometer according to  claim 13 , wherein said response frequency measurement unit further comprises multiple photodiodes, such that light of different polarizations is transferred to different ones of the multiple photodiodes from said polarized splitter, resulting in the at least two temporally-distinct response frequency values. 
     
     
         15 . A method for measuring change in a magnetic field, the method comprising computing a difference between at least two temporally-distinct response frequency values received from a pulsed-mode atomic magnetometer, wherein said computing is performed by a hardware computing unit; wherein said pulsed-mode atomic magnetometer comprises a response frequency measurement unit comprising a vapor cell, a pulsed-mode pump laser and a CW (continuous wave) laser probe, and wherein said pulsed-mode atomic magnetometer is magnetically non-shielded. 
     
     
         16 . A method for measuring a change in a magnetic field, the method comprising:
 providing a response frequency measurement unit comprising a vapor cell, a pulsed-mode pump laser and a probe laser pulsed-mode atomic magnetometer, wherein said response frequency measurement unit is magnetically non-shielded;   irradiating said vapor cell with said pulsed-mode pump laser light while a magnetic field changes;   measuring at least two temporally-distinct responses to the irradiation; and   determining an amount of change to the magnetic field based on a difference between the at least two responses.   
     
     
         17 . The method according to  claim 16 , wherein said irradiating is at a repetition rate of 5 KHz or less.