Numerical calculation of the optical absorption in semiconductor quantum structures

We describe a highly efficient, general-purpose, and easy-to-use method of calculating the optical absorption of semiconductor microstructures. The linear optical susceptibility is obtained by the numerical evaluation of the polarization in real space and real time, using finite differences and the leap-frog scheme. Numerical effort and storage scale as O(N), where N is the number of base elements. The algorithm is suitable for large-scale quantum systems. For illustration, we apply this method to quantum wells in a perpendicular magnetic field, Bat quantum dots, superlattices, coupled multiple quantum wells, and excitons on rough interfaces.