• absorption
• chirality
• coherent
• metamaterials

Coherent absorption (CA) is a linear effect arising when two or more monochro- matic coherent waves interfere in an absorbitive material. Such phenomenon relies on the cooperation between two mechanisms: interference, that traps the waves inside the material, and dissipation, which causes the trapped waves to be absorbed. CA yields the possibility to control the total absorbance of an object, i.e. the portion of intensity subtracted from the incoming beams, by changing their relative phase.
The first experimental proof of coherent control of absorption was reported in 2010, where the phenomenon was realized in the simplest case of a homogeneous Si slab.
To date, a lot of effort has been devoted to investigate CA in different systems ranging from dielectric slabs, to more complex devices such as metamaterials, or strongly coupled quantum excitations.
However, all of these works dealt with a fixed linear polarization or treated all the polarization states equally.
This thesis aims at producing experimental evidence of a polarization dependent coherent ab- sorber. To this end we study two kinds of metamaterial, an anisotropic and a chiral one. In carrying out the work, a special attention is devoted to the concept of chirality and its manifestations.
The results presented in this work could contribute to the extension of the advantages of a CA-based all-optical switching device to general polarization states, i.e elliptically polarized light and, ultimately, circularly polarized light, together with the basis for the realization of an all-in-one automatic controller able to explore the whole surface of the Poincaré sphere, yielding the potential to fully exploit the properties of the scattering operator of the material under analysis.