Light beams with flat-topped profiles.

A necessary condition for generating optical beams with a nearly uniform profile at a certain transverse plane is proposed. This proposal leads to the introduction of a set of light beams with flat-topped profiles. This set of beams can be expressed as a finite series of lowest-order Gaussian modes (TEM(00)) with different parameters. The main features of this set of beams are investigated and compared with those predicted by existing models of flattened Gaussian beams.