Nonlinear optical response of two-dimensional magnetoexcitons

We study the nonlinear optical response of two-dimensional excitons in a perpendicular magnetic field. The transition from two-dimensional behavior in low fields to quasi-zero-dimensional behavior in high fields is investigated, and pronounced interaction effects that are highly field dependent are found. Differential pump-probe spectra are calculated for both continuous-wave and impulsive excitation. It is shown that cyclotron motion can be time resolved with ultrashort optical pulses.