Deformation of Fields Propagating Through Gas Lenses

The concept of a thin lens equivalent to a gas lens is used to calculate distortions of off-axis Gaussian fields in beam waveguides composed of gas lenses. A computational method for the numerical solution of this problem based on the Kirchoff-Huygens diffraction integral is developed. It is shown that off-axis Gaussian fields deform considerably as they travel through a sequence of gas lenses. These deformations are substantial even though the lens distortions may be small. If the light beam deforms it is hard, if not impossible, to steer it back on-axis. This problem can be avoided if some means of beam redirection are used to keep the field on-axis, thus preventing the occurrence of significant beam deformation.