| 1. |
- Arnold, Cord, et al.
(author)
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Nonlinear Bessel vortex beams for applications
- 2015
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In: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 48:9
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Journal article (peer-reviewed)abstract
- We investigate experimentally and numerically the nonlinear propagation of intense BesselGauss vortices in transparent solids. We show that nonlinear Bessel-Gauss vortices preserve all properties of nonlinear Bessel-Gauss beams while their helicity provides an additional control parameter for single-shot precision micro structuring of transparent solids. For sufficiently large cone angle, a stable hollow tube of intense light is formed, generating a plasma channel whose radius and density are increasing with helicity and cone angle, respectively. We assess the potential of intense Bessel vortices for applications based on the generation of hollow plasma channels.
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| 2. |
- Brambilla, E., et al.
(author)
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Three and Four-Modes Parametric Processes in Hexagonally Poled Nonlinear Photonic Crystals
- 2018
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In: OPTICS, PHOTONICS AND LASERS. - : INT FREQUENCY SENSOR ASSOC-IFSA. ; , s. 176-178
-
Conference paper (peer-reviewed)abstract
- We investigate the properties of the field emitted through parametric down-conversion (PDC) in a nonlinear photonics crystal (NPC) with a hexagonal poling pattern, both from a theoretical point of view and with an experiment performed at the University of Insubria. Considering the high gain regime of PDC, we demonstrate the existence of concurrent PDC processes mediated by two noncollinear poling vectors which are coherently coupled and reciprocally stimulated. We find that these non-standard 3-mode and 4-mode interaction processes undergo a substantial enhancement of the parametric gain with respect to the usual 2-mode PDC, and give rise to hot spots order of magnitudes brighter than standard 2-mode fluorescence which have been observed in the source far field. We performed a complete characterization of the source spectral-angular emission, finding a very good agreement between the experiment and the theoretical predictions.
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