Effects of a laser beam profile on Zeeman electromagnetically induced transparency in the Rb buffer gas cell

Abstract

Electromagnetically induced transparency (EIT) due to Zeeman coherences in the Rb buffer gas cell is studied for different laser beam profiles, laser beam radii and intensities from 0.1 to 10 mW cm −2 . EIT line shapes can be approximated by the Lorentzian for wide Gaussian laser beam (6.5 mm in diameter) if laser intensity is weak and for a laser beam profile of the same diameter. Line shapes of EIT become non-Lorentzian for the Gaussian laser beam if it is narrow (1.3 mm in diameter) or if it has a higher intensity. EIT amplitudes and linewidths, for both laser beam profiles of the same diameter, have very similar behaviour regarding laser intensity and Rb cell temperature. EIT amplitudes are maximal at a certain laser beam intensity and this intensity is higher for narrower laser beams. The EIT linewidth estimated at zero laser intensity is about 50 nT or 0.7 kHz, which refers to 1.5 ms relaxation times of Zeeman coherences in 87 Rb atoms in our buffer gas cell. Blocking of the centre of the wide Gaussian laser beam in front of the photo detector yields Lorentzian profiles with a much better contrast to the linewidth ratio for EIT at higher intensities, above ∼2 mW cm −2 .

Higher-order breathers as quasi-rogue waves on a periodic background

“…We additionally show several fully periodic higher-order breathers in Fig. 8, combining conditions ( 23) and (14). In general, the effect of matching to the background is subtle in 3D plots yet abundantly clear in the contour plots.…”

“…[12]. The physics of RWs is getting more attention since a new scheme to excite RWs, such as via electromagnetically induced transparency (EIT) [13][14][15], is proposed [16].…”

Polarization phenomena in coherent excitation of atomic systems: an overview of results

“…In [26], for a mixture of 87 Rb atoms and a buffer gas, neon, in particular, the effect of a test beam, polarized linearly and corresponding to the F 0 = 2 → F = 1 transition, on the EIT signal was studied. The Hanle effect, which implies the presence of a sharp maximum in the bandwidth at zero magnetic field, was used to record the system's enlightening by the test beam.…”

Multi-elliptic rogue wave clusters of the nonlinear Schrödinger equation on different backgrounds

“…The current hot topic in the nonlinear science is to investigate the cause and nature of rogue waves [37]. This research is attracting more attention as well because a new scheme for RWs excitation, via the electromagnetically induced transparency (EIT) [38][39][40], was described recently [41].…”