August 04, 2014

How would the appearance of a cloud change if one were to put some order into the position of water droplets? In this study we considered a more practical system made of tiny (nanometer-scale) holes in a glass-like sheet whose positions can be controlled at will. When these holes are disorderly placed, like droplets in clouds, light bounces around, spreading. We found though that it is possible to control light propagation by tuning this disorder over certain extent: from more transparent, thus allowing light to rapidly escape, to more opaque, retaining light for long times.

We observed that by controlling disorder a severe slow down of the propagation of light, to the point of a complete halt, occurs. The possibility to mold the light scattering, even to trap it, can be useful for a variety of applications, from biosensing to the next generation of all-optical calculators.

(Conley et al, Phys. Rev. Lett. 112, 143901 (2014))

Source:
http://www.ino.it/en/?p2=focus&p=research-focus