Magnetic Field On The Polarization Rotation In A Coherently Prepared Atomic Medium

The dependencies of the polarization rotation on the probe ellipticity and the longitudinal magnetic field have been studied both experimentally and theoretically in a V type electromagnetically induced transparency for 87Rb vapour. The angle of rotation varies periodically with the change in the probe ellipticity and non-linearly with the variation of the magnetic field. We have observed that the plane of polarization is rotated maximum for linearly polarized light and have obtained angle of rotation 0.32 degrees 0.01 degrees for B = 0.036 +/- 0.001 mT while it was 0.0267 degrees +/- 0.0002 degrees without magnetic field. Thus our measurement becomes sensitive to the low magnetic field. A four-level system is considered and the corresponding density matrix equations have been solved analytically to explain these observations theoretically with the help of degenerate and non-degenerate magnetic sub-levels. (c) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement