Linear and nonlinear refractive index changes in monolayer MoSe2

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. Besides, the strong spin-orbit coupling in monolayer MoSe2 causes a significant difference in the peak due to spinning up and down. The RICs due to intra-band transition display only one peak in the THz range, while the inter-band spectra show a series of peaks in the near-infrared optical range, making monolayer MoSe2 be a promising candidate for novel optoelectronic applications.