Four-level N-scheme crossover resonances in Rb saturation spectroscopy in magnetic fields

Abstract

We perform saturated absorption spectroscopy on the D$\_2$ line for room temperature rubidium atoms immersed in magnetic fields within the 0.05-0.13 T range. At those medium-high field values the hyperfine structure in the excited state is broken by the Zeeman effect, while in the ground state hyperfine structure and Zeeman shifts are comparable. The observed spectra are composed by a large number of absorption lines. We identify them as saturated absorptions on two-level systems, on three-level systems in a V configuration and on four-level systems in a N or double-N configuration where two optical transitions not sharing a common level are coupled by spontaneous emission decays. We analyze the intensity of all those transitions within a unified simple theoretical model. We concentrate our attention on the double-N crossovers signals whose intensity is very large because of the symmetry in the branching ratios of the four levels. We point out that these structures, present in all alkali atoms at medium-high magnetic fields, have interesting properties for electromagnetically induced transparency and slow light applications.

Submitted to Physical Review A

References in corpus (1)

• Broadening and intensity redistribution in the Na($3p$) hyperfine excitation spectra due to optical pumping in the weak excitation limit

Cited by in corpus (11)

• Circular dichroism in atomic vapors: magnetically induced transitions responsible for two distinct behaviors
• Dark resonance formation with magnetically-induced transitions: extension of spectral range and giant circular dichroism
• Electromagnetically induced transparency in a V-system with ${}^{87}$Rb vapor in the hyperfine Paschen-Back regime
• Magnetic field--induced modification of selection rules for Rb D${}_2$ line monitored by selective reflection from a vapor nanocell
• Wide range linear magnetometer based on a sub-microsized K vapor cell
• Coherent Optical Processes on Cs D${}_2$ line Magnetically Induced Transitions
• Low-drift Zeeman shifted atomic frequency reference
• Formation of strongly shifted EIT resonances using "forbidden" transitions of Cesium
• Strongest Magnetically Induced Transitions in Alkali Metal Atoms with nuclear spin $3/2$
• An inverted crossover resonance within one Zeeman manifold
• Modulation transfer spectroscopy of ${}^7$Li D1 line