BEAM QUALITY CHANGES PRODUCED BY QUARTIC PHASE TRANSMITTANCES

The effects that quartic phase distortions generate in tridimensional beam quality parameters of laser fields are investigated. Two cases of special interest are considered: a rationally symmetric spherically aberrated lens, and a pair of identical but orthogonal cylindrical spherically aberrated lenses in contact with one another. Analytical expressions for the quality parameters at the output plane of these quartic-phase optical systems are derived. A number of conditions enabling determination in a definite way whether the quality improves or deteriorates are given for several significant kinds of fields. In particular, some general conclusions are found for perfect Gaussian beams that discriminate whether the two-lens system provides better output beam quality than the single-lens system.