title: Evolution of conically diffracted Gaussian beams in free space.
abstract: We present results of our observations on the free space evolution of conically diffracted beams from both single and cascade systems using various combinations of four biaxial crystals of the monoclinic double tungstate family [KGd(WO4)2]. Longitudinal shifts and radii of the Hamilton-Lloyd pair of rings were measured. In each case, the symmetric - forward and backward - evolution of the beam in free space from its focal image plane was monitored and quantified. Theoretical ring plane patterns based on a recently presented theoretical model are also compared to experimental patterns and found to be in good agreement.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Grant
authors.forename: Amin
authors.initials: A
authors.lastname: Abdolvand