US 11,835,603 B2
Optically pumped magnetometer having lasers and optical systems used to derive an intensity of a magnetic field
Akinori Saito, Hamamatsu (JP); Takahiro Moriya, Hamamatsu (JP); Takenori Oida, Hamamatsu (JP); Motohiro Suyama, Hamamatsu (JP); and Tetsuo Kobayashi, Kyoto (JP)
Assigned to HAMAMATSU PHOTONICS K.K., Hamamatsu (JP); and Kyoto University, Kyoto (JP)
Filed by HAMAMATSU PHOTONICS K.K., Hamamatsu (JP); and Kyoto University, Kyoto (JP)
Filed on Jun. 1, 2022, as Appl. No. 17/829,413.
Claims priority of application No. 2021-094324 (JP), filed on Jun. 4, 2021.
Prior Publication US 2022/0390533 A1, Dec. 8, 2022
Int. Cl. G01R 33/26 (2006.01)
CPC G01R 33/26 (2013.01) 16 Claims
OG exemplary drawing
 
1. An optically pumped magnetometer comprising:
at least one cell configured to be filled with an alkali metal vapor, be disposed in a first direction along a measurement target, and form a first cell region and a second cell region on the measurement target;
a pump laser configured to emit pump light for exciting alkali metal atoms;
a probe laser configured to emit probe light including first probe light and second probe light for detecting change in a polarization angle caused by a magnetic field in an excited state of the alkali metal atoms;
a first optical system configured to cause the pump light to be incident on the first cell region in the first direction;
a second optical system configured to cause the pump light having passed through the first cell region to be incident on the second cell region in the first direction;
a third optical system configured to cause the first probe light to be incident on the first cell region in a second direction orthogonal to the first direction;
a fourth optical system configured to cause the second probe light to be incident on the second cell region in the second direction;
a detection portion configured to detect first probe light having passed through the first cell region and second probe light having passed through the second cell region; and
a deriving portion configured to derive an intensity of a magnetic field related to a region having the pump light and the first probe light orthogonal to each other from change in the polarization angle of the first probe light within the first cell region and derive an intensity of a magnetic field related to a region having the pump light having passed through the first cell region and the second probe light orthogonal to each other from change in the polarization angle of the second probe light within the second cell region based on detection results of the detection portion,
wherein the first cell region and the second cell region are formed by multiple cells,
wherein the multiple cells are disposed away from each other in a direction away from the measurement target, and
wherein the deriving portion performs noise removal processing by calculating a difference between an intensity of a magnetic field related to an area within the first cell region and an intensity of a magnetic field related to an area within the second cell region.