| 摘要 |
A magnetic field measuring device having: a magnetic sensor unit that has a glass cell having an alkali metal gas sealed therein and uses the magneto-optical properties of spin-polarized alkali metal to detect a magnetic field; a light source unit for generating excitation light to be introduced into the magnetic sensor unit; a coil unit that is disposed in the same magnetically shielded space as the magnetic sensor unit and applies a static magnetic field and RF magnetic field to the magnetic sensor unit; and a signal processing unit for performing lock-in detection of the detection signal for light that has passed through the glass cell of the magnetic sensor unit, using the lock-in detection output to control the intensity of the static magnetic field generated by the coil unit and the frequency of the RF magnetic field generated by the coil unit, and obtaining a measurement signal that reflects the magnetic field strength of the measurement target within the magnetically shielded space. The light source unit includes a laser, an intensity stabilization unit for controlling an optical modulator that receives the output light of the laser so that the output light intensity of the optical modulator reaches a prescribed value, and a frequency stabilization unit for creating, on the basis of an optical phase obtained from a glass cell for reference that receives one light beam split from the light that has passed through the optical modulator of the intensity stabilization unit, a frequency stabilization control signal that controls the resonator length of the laser. The other light beam split from the light that has passed through the optical modulator of the intensity stabilization unit is made to be the excitation light. |
