Light in and from complex photonic materials  

Prof.dr. D. Wiersma, European Lab. for Non-linear Spectroscopy, Florence, Italy

In the last 20 years a considerable research effort has been dedicated to
light transport phenomena in complex dielectric structures like photonic
crystals and disordered dielectrics.  In disordered systems light follows
a diffusive type of propagation, like electrons in a resistor.
On the other extreme, periodic dielectric structures behave as a crystal
for light waves. In both cases intriguing interference effects can take
place that give rise to a broad scale of physical phenomena.
 
If optical gain is added to a random material, a unique light source is
obtained, often referred to as a random laser. Such random laser
sources combine the emission properties of a regular light bulb with that
of a standard laser and use multiple scattering of light to reach a laser
threshold.
 
The study of how light waves behave in complex photonic structures
is interesting from a fundamental point of view but also has enormous
potential applications in the field of photonics, in active
displays, telecommunications, and medical diagnostics.