Author:Dudley, Angela L; Milione, G; Alfano, RR; Forbes, ADate:2014We present a new all-digital technique to extract the wavefront of a structured light beam. Our method employs non-homogeneous polarization optics together with dynamic, digital holograms written to a spatial light modulator to measure the ...Read more
Author:Roux, FS; Chen, MDate:Sep 2010In an attempt to understand the process whereby the phase modulation due to atmospheric turbulance causes phase singularities (also called optical vortices), the authors investigated the effect of phase perturbations in speckle beams. They ...Read more
Author:Rosales-Guzmán, C; Trichili, A; Dudley, Angela L; Ndagano, B; Salem, ABDate:Oct 2016By combining both the azimuthal and radial components of Laguerre-Gaussian modes with wavelength division multiplexing, we generated >100 information channels. We implemented a laboratory free-space link using 35 Laguerre-Gaussian modes and ...Read more
Author:Roux, FSDate:Oct 2013Optical vortices are always created or annihilated as vortex dipoles — pairs with opposite topological charge. Here a quantity, consisting of the transverse first and second derivatives of the optical field, is derived with which one can ...Read more
Author:Chen, M; Roux, FSDate:Jun 2009The optical vortices that exist in strongly scintillated beams make it difficult for conventional adaptive optics systems to remove the phase distortions. When the least-squares reconstructed phase is removed, the vortices still remain. ...Read more
Author:Litvin, IA; Dudley, Angela L; Forbes, ADate:Aug 2011The authors study theoretically the orbital angular momentum (OAM) density in arbitrary scalar optical fields, and outline a simple approach using only a spatial light modulator to measure this density. They demonstrate the theory in the ...Read more
Author:Belyi, VN; Khilo, NA; Kazak, NS; Ryzhevich, AA; Forbes, ADate:May 2011The authors investigate the generation and transformation of Bessel beams through linear and nonlinear optical crystals. They outline the generation of high-order vortices due to propagation of Bessel beams along the optical axis of uniaxial ...Read more
Author:Sephton, Bereneice C; Dudley, Angela L; Forbes, ADate:Oct 2016Light beams that carry orbital angular momentum are often approximated by modulating an initial beam, usually Gaussian, with an azimuthal phase variation to create a vortex beam. Such vortex beams are well defined azimuthally, but the radial ...Read more
Author:Chen, M; Dainty, C; Roux, FSDate:Aug 2011The authors study numerically the evolution of speckle fields due to the annihilation of optical vortices after the least-squares phase has been removed. A process with multiple steps of least-squares phase removal is carried out to minimize ...Read more
Author:Roux, FSDate:2009The report present the presentation on vortices in Gaussian beams. The presentation was on the polynomial Gaussian beam, Calculation techniques and general properties of polynomial Gaussian beam, Single vortex beams and Gaussian beams with ...Read more
Author:Schulze, C; Naidoo, Darryl; Flamm, D; Schmidt, OA; Forbes, A; Duparr, MDate:Aug 2012We propose a new method to determine the wavefront of a laser beam based on modal decomposition by computer-generated holograms. The hologram is encoded with a transmission function suitable for measuring the amplitudes and phases of the modes ...Read more
Author:Spangenberg, D-M; Dudley, Angela L; Neethling, PH; Rohwer, EG; Forbes, ADate:2014Spatial light modulators are ubiquitous tools for wavefront control and laser beam shaping but have traditionally been used with monochromatic sources due to the inherent wavelength dependence of the calibration process and subsequent phase ...Read more