Space–time design of the tangled C-points and optical vortex chain and loop reactions in paraxial dynamic elliptic speckle fields

Abstract

The unique effect of ‘optical damage’ in photorefractive LiNbO3:Fe crystals produces a developing speckle field in the propagating beam of a He–Ne laser (0.63 μm). Elliptic developing speckle fields were created and investigated thoroughly by means of the Stokes polarimetry and monstardom (Dennis 2008 Opt. Lett. 33 2572). The ergodicity of elliptic speckle fields under the index (star, monstar, lemon) and contour (elliptic, hyperbolic) classifications was revealed experimentally by our measurements for developing speckle fields, measurements for static elliptic speckle fields, as well as theory (Flossmann et al 2008 Phys. Rev. Lett. 100 203902). Both hyperbolic (H) and elliptic (E) diabolos were fixed. All the probable topological structures for the neighbour diabolos in the developing elliptic speckle field were measured. All the measured nucleation/annihilation events occur as H(S)+H(M) reactions. The evolution of the singularities occurs separately in the speckle-field areas with fixed handedness and is realized through minimizing the changes needed for the developing speckle fields at each moment. The general regularities of the elliptic speckle-field development were revealed and confirmed. They occur through the time-limited loop and continuous chain reactions in both single and multiple speckles in 1:4 proportion. Strict morphological scenarios for their evolution were found. Applications of the methods of dynamical singular optics are discussed.