Magnetic field measuring device and method for manufacturing magnetic field measuring device

• US 10,444,300 B2
• Filed: 06/07/2017
• Issued: 10/15/2019
• Est. Priority Date: 06/21/2016
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Ueno, Hitoshi
• Primary Examiner(s): Lee, Seung H
• Application Number:
  US15/616,095
• Publication Number:
  US 20170363695A1
• Time in Patent Office: 860 Days
• CPC Class Codes: G01R 33/032 using magneto-optic devices, e.g. Faraday or Cotton-Mouton effect
• CPC Class Codes: G01R 33/243 Spatial mapping of the polarizing magnetic field
• CPC Class Codes: G01R 33/26 using optical pumping

Abstract

A magnetic field measuring device includes: a first cell and a second cell in which alkali metal atoms are entrapped and which are disposed in this order in a sensing direction of a magnetic field; a first reflective mirror, a second reflective mirror, and an autocollimator as an optical axis detector. Beam light as second polarized light and beam light as fourth polarized light, which are detected by the autocollimator, have orientations of optical axes in the same direction.

Claims

1. A magnetic field measuring device comprising:

a light irradiator that performs irradiation with linearly polarized light;

a first cell and a second cell in which alkali metal atoms are entrapped and which are disposed in this order in a sensing direction of a magnetic field;

a first light branching element that causes the linearly polarized light to branch into first polarized light which is incident to the first cell and second polarized light which is parallel to the first polarized light; and

a second light branching element that causes the linearly polarized light to branch into third polarized light which is incident to the second cell and fourth polarized light which is parallel to the third polarized light,

wherein a position of the second cell is adjusted with respect to the first cell such that an orientation of an optical axis of the second polarized light and an orientation of an optical axis of the fourth polarized light are the same direction.

2. The magnetic field measuring device according to claim 1,

wherein the first light branching element is provided with a first light branching unit that reflects the linearly polarized light, causes the light to be incident to the first cell, and converts the light into the first polarized light, and a first mirror that reflects the linearly polarized light transmitted through the first light branching unit and converts the light into the second polarized light, and

wherein the second light branching element is provided with a second light branching unit that reflects the linearly polarized light, causes the light to be incident to the second cell, and converts the light into the third polarized light, and a second mirror that reflects the linearly polarized light transmitted through the second light branching unit and converts the light into the fourth polarized light.

3. The magnetic field measuring device according to claim 1, further comprising:

an optical axis detector that is capable of detecting the orientation of the optical axis of the second polarized light and the orientation of the optical axis of the fourth polarized light.

4. The magnetic field measuring device according to claim 1, further comprising:

a third cell disposed in a direction orthogonal to the sensing direction with respect to the first cell; and

a fourth cell disposed in a direction orthogonal to the sensing direction with respect to the second cell.

5. The magnetic field measuring device according to claim 4,

wherein the light irradiator is provided with a first light irradiator that irradiates the first cell and the third cell with the linearly polarized light and a second light irradiator that irradiates the second cell and the fourth cell with the linearly polarized light.

6. The magnetic field measuring device according to claim 1, further comprising:

a first reference surface on which the first light branching element is disposed; and

a second reference surface on which the second light branching element is disposed,

wherein a position of the second reference surface is adjustable with respect to the first reference surface.

7. The magnetic field measuring device according to claim 1,

wherein the sensing direction of the magnetic field intersects with an incident direction of the linearly polarized light in the first cell and the second cell.

8. A method for manufacturing a magnetic field measuring device that includes

a light irradiator that performs irradiation with linearly polarized light,

a first cell and a second cell in which alkali metal atoms are entrapped,

a first light branching element that causes the linearly polarized light to branch into first polarized light which is incident to the first cell and second polarized light which is parallel to the first polarized light, and

a second light branching element that causes the linearly polarized light to branch into third polarized light which is incident to the second cell and fourth polarized light which is parallel to the third polarized light,

the method comprising:

disposing the first cell and the second cell in this order in a sensing direction of a magnetic field;

detecting an orientation of an optical axis of the second polarized light and an orientation of an optical axis of the fourth polarized light; and

adjusting a position of the second cell with respect to the first cell such that the orientation of the optical axis of the second polarized light and the orientation of the optical axis of the fourth polarized light are the same direction, based on the result of the detecting of the optical axis.

9. The method for manufacturing a magnetic field measuring device according to claim 8,

wherein the detecting of the optical axis includes, detecting the orientation of the optical axis of the second polarized light, and detecting the orientation of the optical axis of the fourth polarized light, and

wherein the detecting the orientation of the optical axis of the fourth polarized light is performed after the disposing the first and second cells, and the orientation of the optical axis of the fourth polarized light is detected with the detected orientation of the optical axis of the second polarized light as a reference.