Sub-natural width N-type resonance in cesium atomic vapour: splitting in magnetic fields

The sub-natural width N-type resonance in a Λ-system, on the D₂ line of Cs atoms is studied for the first time in the presence of a buffer gas (neon) and the radiations of two continuous narrow-band diode lasers. A L = 1 cm long cell is used to investigate the N-type process. The N-type resonance in a magnetic field for ¹³³Cs atoms is shown to split into seven or eight components, depending on the magnetic field and laser radiation directions. The results obtained indicate that the levels F_g = 3, 4 are the initial and final ones in the N-resonance formation. The experimental results with magnetic field agree well with theoretical descriptions.