2011 International Quantum Electronics Conference (IQEC) and Conference on Lasers and Electro-Optics (CLEO) Pacific Rim incorporating the Australasian Conference on Optics, Lasers and Spectroscopy and the Australian Conference on Optical Fibre Technology, 2011
We demonstrate self-trapped laser beams carrying optical vortices in nematic liquid crystals. We ... more We demonstrate self-trapped laser beams carrying optical vortices in nematic liquid crystals. We experimentally observe astigmatic transformations of vortex beams into spiralling dipole azimuthons accompanied by a nontrivial power-dependent charge-flipping of on-axis phase dislocations.
2011 International Quantum Electronics Conference (IQEC) and Conference on Lasers and Electro-Optics (CLEO) Pacific Rim incorporating the Australasian Conference on Optics, Lasers and Spectroscopy and the Australian Conference on Optical Fibre Technology, 2011
We report on the first experimental observation of higher-order modes guided by soliton-induced w... more We report on the first experimental observation of higher-order modes guided by soliton-induced waveguides in nematic liquid crystals, identifying the power domains where guided modes are supported.
Conference Digest. 2000 Conference on Lasers and Electro-Optics Europe (Cat. No.00TH8505)
ABSTRACT Summary form only given. We report on accurate measurements of layer thicknesses, modal ... more ABSTRACT Summary form only given. We report on accurate measurements of layer thicknesses, modal effective indices and guided-wave losses. The thickness in the multilayer have been measured through Kiessig fringe analysis in X-ray reflectometry. This lead to an accurate estimation of AlGaAs percentage in MBE grown GaAs-AlGaAs superlattices
2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference (CLEO EUROPE/EQEC), 2011
ABSTRACT We generate self-trapped vortices in nematic liquid crystals and observe their transform... more ABSTRACT We generate self-trapped vortices in nematic liquid crystals and observe their transformations into spiraling dipole azimuthons. We demonstrate experimentally and discuss theoretically nonlinearity-induced charge-flipping of on-axis phase dislocation via topological reactions resembling pitchfork bifurcations.
Quadratic interactions involving three distinct waves can be exploited for all-optical signal pro... more Quadratic interactions involving three distinct waves can be exploited for all-optical signal processing both in the plane wave limit and in the spatial solitary-wave case. For the specific case of Type II Second-Harmonic Generation in bulk KTP, we have predicted and demonstrated all-optical transistor action with small signal gain and angular steering and switching of spatial simultons. All the phenomena rely exclusively on inputs at the same fundamental frequency
We report on near-infrared waveguide photodetectors realized in germanium evaporated at low tempe... more We report on near-infrared waveguide photodetectors realized in germanium evaporated at low temperature on silicon-on-insulator optical chips. We discuss the fabrication and integration and show experimental results in terms of dark current, responsivity and signal to noise ratio.
We report on the observation of switching and self-pulsing of guided modes in a planar lithium ni... more We report on the observation of switching and self-pulsing of guided modes in a planar lithium niobate waveguide due to the photorefractive formation of holographic gratings. The technique is a powerful tool for directly measuring the erasure time of the gratings and provides insight into the dynamic-state photorefractive effect.
Abstract We report the experimental observation of a transitory state during the build-up of phot... more Abstract We report the experimental observation of a transitory state during the build-up of photorefractive effects in lithium niobate slab waveguides. By prism coupling light into and out of the structure, we observed a relatively fast time-dependent spatial distortion of the output coupled beam. The experimental results are interpreted qualitatively in terms of a dynamic-state photorefractive effect, due to the photo-excitation of impurity-localized dipoles. A model of this mechanism is briefly outlined in conjunction with the formation of a holographic grating due to in-plane light scattering.
2011 International Quantum Electronics Conference (IQEC) and Conference on Lasers and Electro-Optics (CLEO) Pacific Rim incorporating the Australasian Conference on Optics, Lasers and Spectroscopy and the Australian Conference on Optical Fibre Technology, 2011
We demonstrate self-trapped laser beams carrying optical vortices in nematic liquid crystals. We ... more We demonstrate self-trapped laser beams carrying optical vortices in nematic liquid crystals. We experimentally observe astigmatic transformations of vortex beams into spiralling dipole azimuthons accompanied by a nontrivial power-dependent charge-flipping of on-axis phase dislocations.
2011 International Quantum Electronics Conference (IQEC) and Conference on Lasers and Electro-Optics (CLEO) Pacific Rim incorporating the Australasian Conference on Optics, Lasers and Spectroscopy and the Australian Conference on Optical Fibre Technology, 2011
We report on the first experimental observation of higher-order modes guided by soliton-induced w... more We report on the first experimental observation of higher-order modes guided by soliton-induced waveguides in nematic liquid crystals, identifying the power domains where guided modes are supported.
Conference Digest. 2000 Conference on Lasers and Electro-Optics Europe (Cat. No.00TH8505)
ABSTRACT Summary form only given. We report on accurate measurements of layer thicknesses, modal ... more ABSTRACT Summary form only given. We report on accurate measurements of layer thicknesses, modal effective indices and guided-wave losses. The thickness in the multilayer have been measured through Kiessig fringe analysis in X-ray reflectometry. This lead to an accurate estimation of AlGaAs percentage in MBE grown GaAs-AlGaAs superlattices
2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference (CLEO EUROPE/EQEC), 2011
ABSTRACT We generate self-trapped vortices in nematic liquid crystals and observe their transform... more ABSTRACT We generate self-trapped vortices in nematic liquid crystals and observe their transformations into spiraling dipole azimuthons. We demonstrate experimentally and discuss theoretically nonlinearity-induced charge-flipping of on-axis phase dislocation via topological reactions resembling pitchfork bifurcations.
Quadratic interactions involving three distinct waves can be exploited for all-optical signal pro... more Quadratic interactions involving three distinct waves can be exploited for all-optical signal processing both in the plane wave limit and in the spatial solitary-wave case. For the specific case of Type II Second-Harmonic Generation in bulk KTP, we have predicted and demonstrated all-optical transistor action with small signal gain and angular steering and switching of spatial simultons. All the phenomena rely exclusively on inputs at the same fundamental frequency
We report on near-infrared waveguide photodetectors realized in germanium evaporated at low tempe... more We report on near-infrared waveguide photodetectors realized in germanium evaporated at low temperature on silicon-on-insulator optical chips. We discuss the fabrication and integration and show experimental results in terms of dark current, responsivity and signal to noise ratio.
We report on the observation of switching and self-pulsing of guided modes in a planar lithium ni... more We report on the observation of switching and self-pulsing of guided modes in a planar lithium niobate waveguide due to the photorefractive formation of holographic gratings. The technique is a powerful tool for directly measuring the erasure time of the gratings and provides insight into the dynamic-state photorefractive effect.
Abstract We report the experimental observation of a transitory state during the build-up of phot... more Abstract We report the experimental observation of a transitory state during the build-up of photorefractive effects in lithium niobate slab waveguides. By prism coupling light into and out of the structure, we observed a relatively fast time-dependent spatial distortion of the output coupled beam. The experimental results are interpreted qualitatively in terms of a dynamic-state photorefractive effect, due to the photo-excitation of impurity-localized dipoles. A model of this mechanism is briefly outlined in conjunction with the formation of a holographic grating due to in-plane light scattering.
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