Abstract
A laser-atom interaction simulator derived from quantum electrodynamics (LASED) is presented, which has been developed in the python programming language. LASED allows a user to calculate the time evolution of a laser-excited atomic system. The model allows for any laser polarization, a Gaussian laser beam profile, a rotation of the reference frame chosen to define the states, and an averaging over the Doppler profile of an atomic beam. Examples of simulations using LASED are presented for excitation of calcium from the 4¹S₀ state to the 4¹P₁ state, for excitation from the helium 3¹D₂ state excited by electron impact to the 10¹P₁ state, and for laser excitation of caesium via the D₂ line.