  Numerical solutions for laser-matter interaction in Schr\"odinger equation
has many applications in theoretical chemistry, quantum physics and condensed
matter physics. In this paper we introduce a methodology which allows, with a
small cost, to extend any fourth-order scheme for Schr\"odinger equation with
time-indepedent potential to a fourth-order method for Schr\"odinger equation
with laser potential. These fourth-order methods improve upon many leading
schemes of order six due to their low costs and small error constants.
