Polarization rotation spectral profiles for the D2 line of ⁸⁷Rb atoms: theory and experiment

Abstract

We present a theoretical and experimental study of the polarization rotation of a linearly polarized probe beam scanning across all of the neighboring hyperfine levels (Fe = 1 and 2) with a circularly polarized pumping beam resonant on the transition of the D2 line of 87Rb atoms. The experimental results match well with the results calculated from the full-level density matrix equations considering laser phase noise, which hinders observations of narrow lines with linewidths of ∼90 kHz, as calculated in polarization rotation spectra for the first time.

Theoretical and Experimental Study of Optimization of Polarization Spectroscopy for the D2 Closed Transition Line of 87Rb Atoms

“…As will be seen later, the calculations without considering the coherence terms failed to predict the experimental results because a relatively strong pump beam was used in the experiment. An accurate analytical calculation for the PS for the F g = 0 → F e = 1 transition was reported [29], and accurate numerical calculations of the sub-Doppler DAVLL [12,13] and polarization rotation were also recently reported [30].…”

“…(2) F e ,m e ;F g ,m g is the density matrix element F e , m e ρ (2) F g , m g , where ρ (2) is the component of the optical coherence responsible for the probe absorption [30]. The density matrix elements of the operator ρ (2) were calculated by solving the density matrix equations.…”

“…The density matrix elements of the operator ρ (2) were calculated by solving the density matrix equations. The methods for solving the density matrix equations are twofold: one is the direct calculation of the temporal differential equations [13], and the other is the steady-state calculation by including a transit-time relaxation constant [12,30]. First, we used a steady-state calculation method because it provides a highly efficient and fast method.…”

Electromagnetically induced absorption in Rb atoms with circular polarization of laser beams: Effects of neighboring transitions

“…In addition, the populations are decomposed as where j runs for all the magnetic sublevels [17] . The optical coherences between the sublevels with are decomposed as follows [17] , [18] : where . The absorption coefficient of the probe beam is given by where Γ is the decay rate of the excited, is the atomic number density, and u is the most probable speed in the vapor cell.…”