Influence of a laser beam radial intensity distribution on Zeeman electromagnetically induced transparency line-shapes in the vacuum Rb cell

Abstract

Experimental and theoretical analyses show the effect of laser beam radial intensity distribution on line-shapes and line-widths of the electromagnetically induced transparency (EIT). We used Gaussian and (flat top) laser beam profiles, coupling the D 1 transition of 87 Rb atoms in the vacuum cell in the Hanle experimental configuration. We obtained non-Lorentzian EIT line-shapes for a Gaussian laser beam, while line-shapes for a laser beam profile are very well approximated with Lorentzian. EIT line-widths, lower for Gaussian than for , show nonlinear dependence on laser intensity for both laser beam profiles. EIT amplitudes have similar values and dependence on laser intensity for both laser beams, showing the maximum at around 0.8 mW cm −2. Differences between the EIT line-shapes for the two profiles are mainly due to distinct physical processes governing atomic evolution in the rim of the laser beam, as suggested from the EIT obtained from the various segments of the laser beam cross-section.

Pump beam influence on spin polarization homogeneity in the nuclear magnetic resonance gyroscope

“…The influence of the beam inhomogeneity has already been a hot issue in the research of atomic clocks, because it was discovered to have non-negligible impact on the electromagnetically induced absorption and limit the sensor performance during the development of chip scale atomic clocks. The analysis was based on Bloch equations for the density matrix under Gaussian and flat-topped laser beams [12,13], and the importance of the beam profile was demonstrated according to the simulations and experimental results. The inhomogeneity of spin polarization also limited the performance of atomic magnetometers.…”