In this work, we study the linear, the third-order nonlinear, and the total refractive index changes (RICs) caused by both intra- and inter-band transitions in monolayer MoSe2 in the presence of a magnetic field by using the compact density matrix approach. The results show that RICs display the blue-shift behavior with the increase of the magnetic field. The Zeeman fields do not affect the peak positions but reduce slightly peak intensities. |