Inhomogeneity-driven optical rogue waves through obstacles

RW

 

In a speckle pattern, light is organized in disordered fashion with maxima and minima of intensity. The multiple wave components underlying  an inhomogeneous  optical rogue wave may give rise to exceptional maxima of intensity which are similar to unpredictable rogue waves appearing from nowhere in the ocean. Here, we demonstrate that the inhomogeneity-driven optical rogue waves may be fully tailored through adaptive optics and that may be also activated behind fully reflective obstacles.

Disorder Induced Self-Focusing

Focusing

 

In photonics, disorder is usually seen as a bad feature decreasing the efficiency of optical elements and driving light far from your target.

In this paper we demonstrate that the reverse is possible: disorder transforms two de focusing-plastics into a self-focusing metamaterial.

By exploiting a phenomenon named Transversal Anderson localization it is possible to exploit scattering events to constrain light into a tiny space, and exploit very cheap disordered optical to bring information at large distances.

By putting together Transverse localization and Nonlinearity it si possible to achieve complete control of a light beam, defining the degree of localization and its position.

“Light Localisation and Lasing” out in January

L_LOC

I’have been happy to part of the “Light Localisation and Lasing”  team: a comprehensive book on light, lasing and disorder.

Out in January 2015!

“The properties of quasi-random and random photonic systems have been extensively studied over the last two decades, but recent technological advances have opened new horizons in the field, providing better samples and devices. New optical characterization techniques have enhanced understanding of the novel and fundamental properties of these systems. This book examines the full hierarchy of these systems, from 1D to 2D and 3D, from photonic crystals and random microresonator chains to quasi crystals.”

Disorder Induced Self Focusing


Disorder induced_focusing

In a nonlinear optical material, the refractive index varies with the optical intensity. In general thermal nonlinearity produces a de-focusing effect. In this paper  we demonstrate that disorder changes the terms around and transform a de-focusing nonlinearity into a focusing one. When the thermal nonlinearity is activated, the two materials composing the optical fiber respond differently and the refractive index mismatch increases, enhancing the strength of the transversal Anderson localization. In a nutshell we demonstrate a nonlinearly enhanced transverse Anderson localization.

The mode-locking transition of random lasers

mode_locking 

The discovery of the spontaneous mode-locking of lasers, that is, the self-starting synchronous oscillation of electromagnetic modes in a cavity, has been a milestone of photonics allowing the realization of oscillators delivering ultrashort pulses. In a paper published on Nature Photonics we shown that the random laser can be continuously driven from a configuration exhibiting weakly interacting electromagnetic resonances to a regime of collectively oscillating strongly interacting modes.