ABSTRACT
In 1974 Kalnins and Miller [17] found a solution to the paraxial propagation equation in the form of Airy functions. In 1979, Berry and Balazs [18] considered non-broadening wave packets in quantum mechanics. In 1994, Besieris et al. [19] found a solution to the 2D paraxial equation () https://www.w3.org/1998/Math/MathML"> 2 i ∂ U ∂ ξ + ∂ 2 U ∂ s x 2 + ∂ 2 U ∂ s y 2 = 0 https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429321610/47b35bc2-617c-4920-b4c9-1c82a672da14/content/eq1.tif" xmlns:xlink="https://www.w3.org/1999/xlink"/>
