Abstract

It was shown by Durnin et al [1] that the Helmholtz equation for the free space propagation of light beams possesses exact eigenmode solutions that, in principle, describe beams which propagate indefinitely without any distortion due to diffraction. The problem is that these “nondiffracting” solutions, the simplest of which is proportional to the zero order Bessel function, are of infinite transverse extent and energy, and therefore cannot be realised in practice. However, Durnin et al were able to demonstrate in experiments with beams of finite size that the characteristics of nondiffraction could be sustained over long distances [1].

© 1996 Optical Society of America