Random photonics

A paradigmatic example of complexity in photonics is offered by the propagation of a light beam in a disordered, linear or nonlinear, media. In this framework, our interest is focused on both understanding the complex physical process behind the scenario of the observable phenomena and the exploitation of disorder to develop disordered-based optical devices, like novel laser sources and tool for optical manipulation and diagnostic.

When electromagnetic radiation travels through a scattering medium, depending on the competition between the length scales involved in the propagation process, i.e., the wavelength, the length scale of the system structure, the photons transport mean free path, ℓ, and the dimensionality of the whole system, a transition from a diffusive propagation regime to light localization can be supported.

The comprehension of the physical mechanisms behind is of paramount importance in terms of fundamental research and possible application as demonstrated by our results in this field.

Anderson localization

We have numerically studied the Anderson localization (AL) in 3D disordered systems, where its experimental demonstration is particularly tricky because of the restrictive Ioffe-Regel criterion. We employ an ab initio approach by using a finite difference time domain (FDTD) code in order to simulate a time-of-flight experiment to demonstrate the optical AL in micron-sized samples.

We also used the FDTD code to investigate the effect of disorder on the optomechanical forces.… Read the rest

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Random Laser

Random lasers (RLs) are photonic devices whose lasing feedback is based on the multiple scattering of light by disordered structures included into an optically active medium. The spectral features of a RL arise from the delicate balance between the optical gain and the scattering efficiency of the disordered matrix. We fabricate and we do experiments on miniaturised random lasers to study the behaviour of light entrapped at micron scale and to propose novel photon devices.