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Caustics and Rogue Waves in an Optical Sea.

Mathis A, Froehly L, Toenger S, Dias F, Genty G, Dudley JM - Sci Rep (2015)

Bottom Line: Although most studies in optics have focussed on how nonlinearity can drive rogue wave emergence, purely linear effects have also been shown to induce extreme wave amplitudes.Intensity peaks satisfying statistical criteria for rogue waves are seen especially in the case of the caustic network, and are associated with broader spatial spectra.In addition, the electric field statistics of the intermediate pattern shows properties of an "optical sea" with near-Gaussian statistics in elevation amplitude, and trough-to-crest statistics that are near-Rayleigh distributed but with an extended tail where a number of rogue wave events are observed.

View Article: PubMed Central - PubMed

Affiliation: Institut FEMTO-ST, UMR 6174 CNRS-Université de Franche-Comté, Besançon, France.

ABSTRACT
There are many examples in physics of systems showing rogue wave behaviour, the generation of high amplitude events at low probability. Although initially studied in oceanography, rogue waves have now been seen in many other domains, with particular recent interest in optics. Although most studies in optics have focussed on how nonlinearity can drive rogue wave emergence, purely linear effects have also been shown to induce extreme wave amplitudes. In this paper, we report a detailed experimental study of linear rogue waves in an optical system, using a spatial light modulator to impose random phase structure on a coherent optical field. After free space propagation, different random intensity patterns are generated, including partially-developed speckle, a broadband caustic network, and an intermediate pattern with characteristics of both speckle and caustic structures. Intensity peaks satisfying statistical criteria for rogue waves are seen especially in the case of the caustic network, and are associated with broader spatial spectra. In addition, the electric field statistics of the intermediate pattern shows properties of an "optical sea" with near-Gaussian statistics in elevation amplitude, and trough-to-crest statistics that are near-Rayleigh distributed but with an extended tail where a number of rogue wave events are observed.

No MeSH data available.


Computed probability distributions from peak height analysis of the intensity patterns shown in Figs 2 and 3.Results are shown both for (a) partially-developed speckle and (b) a caustic network. The red asterisks and red dashed line correspond to numerical results, the black circles and black dashed line correspond to experimental results. The label IRW indicates the rogue wave intensity criterion.
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f4: Computed probability distributions from peak height analysis of the intensity patterns shown in Figs 2 and 3.Results are shown both for (a) partially-developed speckle and (b) a caustic network. The red asterisks and red dashed line correspond to numerical results, the black circles and black dashed line correspond to experimental results. The label IRW indicates the rogue wave intensity criterion.

Mentions: To interpret these results in the framework of optical rogue waves, it is necessary to compute the statistics of the intensity peak heights. In particular, for both the numerical and experimental results in Figs 2, 3, we perform two-dimensional peak detection over the spatial intensity patterns, and then compute the corresponding probability histograms (see Methods for details), and these are shown in Fig. 4. Results from simulations (red asterisks) and experiments (black open circles) are compared for the cases of (a) partially-developed speckle and (b) a caustic network respectively as indicated.


Caustics and Rogue Waves in an Optical Sea.

Mathis A, Froehly L, Toenger S, Dias F, Genty G, Dudley JM - Sci Rep (2015)

Computed probability distributions from peak height analysis of the intensity patterns shown in Figs 2 and 3.Results are shown both for (a) partially-developed speckle and (b) a caustic network. The red asterisks and red dashed line correspond to numerical results, the black circles and black dashed line correspond to experimental results. The label IRW indicates the rogue wave intensity criterion.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526884&req=5

f4: Computed probability distributions from peak height analysis of the intensity patterns shown in Figs 2 and 3.Results are shown both for (a) partially-developed speckle and (b) a caustic network. The red asterisks and red dashed line correspond to numerical results, the black circles and black dashed line correspond to experimental results. The label IRW indicates the rogue wave intensity criterion.
Mentions: To interpret these results in the framework of optical rogue waves, it is necessary to compute the statistics of the intensity peak heights. In particular, for both the numerical and experimental results in Figs 2, 3, we perform two-dimensional peak detection over the spatial intensity patterns, and then compute the corresponding probability histograms (see Methods for details), and these are shown in Fig. 4. Results from simulations (red asterisks) and experiments (black open circles) are compared for the cases of (a) partially-developed speckle and (b) a caustic network respectively as indicated.

Bottom Line: Although most studies in optics have focussed on how nonlinearity can drive rogue wave emergence, purely linear effects have also been shown to induce extreme wave amplitudes.Intensity peaks satisfying statistical criteria for rogue waves are seen especially in the case of the caustic network, and are associated with broader spatial spectra.In addition, the electric field statistics of the intermediate pattern shows properties of an "optical sea" with near-Gaussian statistics in elevation amplitude, and trough-to-crest statistics that are near-Rayleigh distributed but with an extended tail where a number of rogue wave events are observed.

View Article: PubMed Central - PubMed

Affiliation: Institut FEMTO-ST, UMR 6174 CNRS-Université de Franche-Comté, Besançon, France.

ABSTRACT
There are many examples in physics of systems showing rogue wave behaviour, the generation of high amplitude events at low probability. Although initially studied in oceanography, rogue waves have now been seen in many other domains, with particular recent interest in optics. Although most studies in optics have focussed on how nonlinearity can drive rogue wave emergence, purely linear effects have also been shown to induce extreme wave amplitudes. In this paper, we report a detailed experimental study of linear rogue waves in an optical system, using a spatial light modulator to impose random phase structure on a coherent optical field. After free space propagation, different random intensity patterns are generated, including partially-developed speckle, a broadband caustic network, and an intermediate pattern with characteristics of both speckle and caustic structures. Intensity peaks satisfying statistical criteria for rogue waves are seen especially in the case of the caustic network, and are associated with broader spatial spectra. In addition, the electric field statistics of the intermediate pattern shows properties of an "optical sea" with near-Gaussian statistics in elevation amplitude, and trough-to-crest statistics that are near-Rayleigh distributed but with an extended tail where a number of rogue wave events are observed.

No MeSH data available.