Anderson localization is a sophisticated phenomenon which is still not completely understood. In a recent paper, we propose a comprehensive mean field theory, (a combination of an effective-medium theory for transverse disorder with the self-consistent localization theory), which covers the relevant aspects of the phenomenon in the transverse case, that is in the case of light propagating in a system invariant along propagation direction and with the disorder on the transverse plane.
In particular, we explain the focusing mechanism leading to the establishment of narrow transparent channels along a disordered optical fiber.
Disorder is usually connected with opacity: the impossibility to transmit information due to the randomization of light paths. On the other hand, disorder is also responsible for a peculiar phenomenon which is the Anderson localization, trapping light into standing waves occupying a tiny space.
By exploiting light localization into an optical fiber, we demonstrated (in a recent journal paper) that disorder may be used to host single-modes: the purest form of light transmission allowing for light traveling without interfering with other optical paths. In this case, the disorder is responsible for a purer form of transparency and not for opacity.
The result may found applications in endoscopy and telecommunications.