Determination of topological charges of polychromatic optical vortices.
We introduce a simple, single beam method for determination of the topological charge of polychromatic optical vortices. It is based on astigmatic transformation of singular optical beams, where the intensity pattern of a vortex beam acquires a form of dark stripes in the focal plane of a cylindrical lens. The number of the dark stripes is equal to the modulus of the vortex topological charge, while the stripe tilt indicates the charge sign. We demonstrate experimentally the effectiveness of this technique by revealing complex topological structure of polychromatic singular beams.
Denisenko
Vladimir
V
Nonlinear Physics Centre, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200, Australia.
Shvedov
Vladlen
V
Desyatnikov
Anton S
AS
Neshev
Dragomir N
DN
Krolikowski
Wieslaw
W
Volyar
Alexander
A
Soskin
Marat
M
Kivshar
Yuri S
YS
D003116:Color; D003198:Computer Simulation; D008027:Light; D008962:Models, Theoretical; D012031:Refractometry / Q000379:methods*; D012542:Scattering, Radiation