Ring-Shaped Spatial Photoluminescence Profiles in Two-Dimensional Semiconductors

We theoretically study the ring-shaped spatial photoluminescence (PL) profile in two-dimensional semiconductors. We numerically solve the nonlinear equation of motion for polarizations initially generated by a normally incident excitation light pulse. When the excitation light amplitude exceeds the critical value, the ring-shaped PL profile is formed. A double peak structure is also found for sufficiently strong excitations.