Magnetic sensor for measuring a magnetic field using optical pumping method

A magnetic sensor for measuring a magnetic field using an optical pumping method, comprising:

• a first gas in which a valence electron is composed of an odd number of atoms or ions;
• a probe light source which causes first circular polarized light to be incident on the first gas;
• a second gas in which a valence electron arranged on an optical path of second circular polarized light that is the first circular polarized light transmitted through the first gas is composed of an odd number of atoms or ions;
• an AC magnetic field generator which generates an AC magnetic field in a direction intersecting with an optical axis of the first circular polarized light and the second circular polarized light for the first gas and the second gas and generates magnetic resonance;
• a bias magnetic field generator which generates bias magnetic fields in a direction parallel to the optical axis of the first circular polarized light and the second circular polarized light with different intensities for the first gas and the second gas and differentiates the optical transmittance of the first circular polarized light in the first gas from the optical transmittance of the second circular polarized light in the second gas;
• and
• a detector which detects a light amount of the first circular polarized light and third circular polarized light that is the second circular polarized light transmitted through the second gas, the magnetic field being measured by calculating a difference in light amount with the detector between the first circular polarized light and the third circular polarized light.