Photonic Glasses

Multiple Light Scattering

Scattering of light in diffusive media is usually considered an inevitable perturbation or even a nuisance. Through repeated scattering and random interferences, it destroys both the spatial and the temporal coherence of any laser illumination. At the spatial level, it gives rise to the well know “speckle” interference patterns. At the temporal (or spectral) level, a short pulse entering a scattering media will see its length greatly extended due to the multiplicity of short and long paths light can take before exiting the medium.
Scattering media is however an interesting playground to test important physics theories at the crossing of optics, condensed matter physics, statistical physics, chaos, to name just a few. The possibility of continuously varying the complexity of the structures from totally disordered (like suspensions in liquid) to ordered structures (like photonics crystals), from solid to granular or even liquid state, from simple scattering to resonant scattering, absorption, or even gain medium open endless possibilities.

Light diffusion
Introduction to multiple light scattering and diffusion
Light propagation in a disordered media is dominated by multiple scattering, which often is duffisive and rich of fashinating effects.
Disordered Photonics
Photonic glasses: a novel random material
Novel nanophotonic materials! A disordered assembly of monodisperse spheres can present macroscopic dispersion effects which are not due to the material intrinsic properties but to Mie resonances of the constituent dielectric spheres.
Disordered Photonics
Vacancy-doped photonic crystals
We present a photonic crystal with a controlled density of vancacies randomly distributed in the system. This is the first attempt to grow ordered photonic materials with a fine control over the extrinsic disorder.
Interference in random media
Interference and light transport in random media

Interfernce survives multiple scattering, giving rise to everyday phenomena like speckle or more subtile ones like Coherent backscattering and Anderson localization of light.

Random lasing
Random Lasing and 3D-mode lasing

a special kind of laser with no coherent feedback, in which 3D diffusive or in general volume modes lase when stimulated emission dominates