Non-linear Faraday rotation on simple transitions in samarium vapour

New results demonstrating the dramatic changes to the form and magnitude of the resonant Faraday rotation with laser intensity, buffer gas pressure and magnetic field strength are presented for the transitions 4f 6 6s 2 7 F 0 -4f 6 6s6p 5 D 1 at 621 nm and 4f 6 6s 2 7 F 1 -4f 6 6s6p 5 D 0 at 654 nm. For both transitions, exact analytical solutions to the steady-state density matrix equations are possible and have been used. The experimental results show good qualitative agreement with the theoretical predictions. In the case of the 654 nm line Zeeman coherence occurs in the ground state and can be achieved at lower laser intensities than for the 621 nm line under comparable conditions.