Localization, coupling and correlation of light waves in two-dimensional disordered photonic systems
by
Francesco Riboli(INO-CNR)
→
Europe/Rome
Aula 6 (Dipartimento di Fisica - Ed. E.Fermi)
Aula 6
Dipartimento di Fisica - Ed. E.Fermi
Description
The ability of disordered systems to diffuse or localize light waves depends
on the dimensionality of the system and the “strength” of its structural
disorder. While on one hand the possibility of light localization in
three-dimensional systems is still an open and lively debated question,
localized states have been already observed and well characterized for
systems with lower dimensionalities. Two-dimensional disordered systems thus
represent the perfect playground for testing theoretical models and
investigate novel transport regimes of waves that possibly go beyond the
standard picture cast by the self-consistent theory of localization.
In this talk I will discuss some key aspects behind light localization in
two-dimensional disordered photonic systems. The local density of optical
states (LDOS) is characterized by isolated resonances with finite spectral
width and finite spatial extent [1]. The spectral and spatial distributions
of the LDOS profile can be tuned by changing the average strength of
structural disorder, while the mutual coupling between resonances can be
selectively modulated by locally engineering the structural disorder [2].
Finally, a statistical study of LDOS spectra is performed by means of
correlation spectroscopy techniques and compared to the self-consistent
theory of localization. We observe the expected universal renormalization of
the Boltzmann diffusion coefficient D/DB, but also non-universal
contributions that are sensitive to subwavelength features of the material
[3].
[1] F. Riboli et al. “Anderson localization of near-visible light in two
dimensions” Opt. Lett. 36, 127-129 (2011).
[2] F. Riboli et al. “Engineering of light confinement in strongly
scattering disordered media” Nat. Mater. 13, 720 (2014).
[3] F. Riboli et al. “Tailoring correlations of the local density of
states in disordered photonic materials” arXiv:1609.01975v1 (2016).
