Deformation of Fields Propagating Through Gas Lenses

Interest in optical communications has stimulated research to find a suitable optical transmission medium. The beam waveguide first suggested by Goubau 1 appears to be an efficient optical waveguide. It is composed of lenses which periodically refocus the light beam, counteracting its tendency to spread apart by diffraction. Gas lenses have been suggested as focusing elements of beam waveguides.2-3-4 Of the various types of gas lenses, the tubular gas lens, Fig. 1(a), has been studied in some detail.3-4 This gas lens can be represented by an equivalent thin lens which is warped to fit the shape of the principal surface of the gas lens and which is given its focal length with the proper dependence on its radius. It was shown in Ref. 5 that ray trajectories through 100 gas lenses coincide closely with ray trajectories through the corresponding equivalent lenses. Replacing the complicated gas lens with the equivalent thin lens simplifies considerably the study of beam waveguides composed of gas lenses. In this paper, we will make use of the equivalent thin lens concept to investigate the propagation of wave fields through a beam waveguide of 1345