Use of Atomic Spectroscopy for Measuring Strong Inhomogeneous Magnetic Fields

The selective reflection (SR) spectrum of laser light from the boundary of the surface of the dielectric window of a spectroscopic nanocell with pairs of rubidium atoms is used to measure a magnetic field applied to the nanocell. A method is proposed for calculating the magnetic induction B in the range of 0.1–6.0 kG based on the ratio of the frequency intervals between atomic transitions, which simplifies the determination of B; in particular, there is no need for a reference spectrum at B = 0. A 300-nm column of Rb atom vapor is used to implement the SR process; atomic processes with a sub-Doppler spectral width of 80–90 MHz take place. This leads to frequency separation of transitions in the SR spectrum. The SR spectrum can be analyzed with the aid of a specially created computer program that speeds up the data processing. The small thickness of the vapor column makes it possible to attain high spatial resolution, which is important in the case of inhomogeneous magnetic fields.