Solitonization of Anderson localisation and optical-event horizons

In a paper in arXiv, Mohammed F. Saleh, Claudio Conti and Fabio Biancalana show that the solitonization of the Anderson localization and the formation of optical horizons by cluster of solitons explain the rogue-solitons in supercontinuum generation.

This is complex photonics !

Turbulent Transitions in Optical Wave Propagation

In a paper published in Phys. Rev. Lett. , D. Pierangeli, F. Di Mei,  G. Di Domenico, A. J. Agranat, C. Conti, and E. Del Re, report the direct observation of the onset of turbulence in propagating one-dimensional optical waves. The transition occurs as the disordered hosting material passes from being linear to one with extreme nonlinearity. As the response grows, increased wave interaction causes a modulational unstable quasihomogeneous flow to be superseded by a chaotic and spatially incoherent one. Statistical analysis of high-resolution wave behavior in the turbulent regime unveils the emergence of concomitant rogue waves. The transition, observed in a photorefractive ferroelectric crystal, introduces a new and rich experimental setting for the study of optical wave turbulence and information transport in conditions dominated by large fluctuations and extreme nonlinearity.

Biomimetic Random Lasers

Biometic random lasers

Living organisms have evolved well-adapted structures and
materials over geological eras. Through evolutional selection,
nature has devised effective solutions to all sorts of complicated
real-world problems and, following Leonardo Da Vinci,
humans have looked at nature to reach answers. The young
field of biomimetics has given rise to new technologies inspired
by nature’s strategy for materials and devices optimized from
the macroscale to the nanoscale.

Neda Ghofraniha, Luca La Volpe, Daniel Van Opdenbosch, Cordt Zollfrank, and Claudio Conti realize a novel random laser device made by biotemplated paper, and demonstrate the control of mode size and interaction. The work was published in Advanced Optical Materials.


Gamow, Batman and the shocks

Shock generation is a leading topic in nonlinear physics and optics. Shock waves occur whenever one enters highly nonlinear regimes either in time or in space. The origin of the undular bores is among the mysterious dynamics of shock wave generation. The undular bores are the fast oscillations that regularize the wave-breaking after the shock; their features are very difficult to understand theoretically.

A typical phenomenon is the appearance of the Batman ears in the optical intensity when the shock occurs; these “ears” are very pronounced peaks limiting the region of the shock and including undulars bores. Figures above show the Batman ears in the far field of a shock wave genereated in the spatial nonlinear optical propagation. Beyond numerical simulations, we do not have a complete theoretical description of this effect.

In a paper published in Optics Express (arXiv:1601.05796)Maria Chiara Braidotti, Silvia Gentilini, and Claudio Conti show that Gamow vectors of the reversed harmonic oscillator provide a new theoretical tool for the quantitative description of spatial shock waves in nonlocal media. The analytical calculations perfectly reproduce our experiments. This opens a number of possibilities for describing and controlling the shock waves in highly nonlocal and non-instantaneous media. The results also show the validity of the novel theoretical methods inherited by the so-called “time-asymmetric quantum-mechanics.”

The picture above shows the comparison between experiments and the analytically calculated Gamow vectors.