In this chapter, we review some recent developments in the field of
photonics: cloaking, whereby an object becomes invisible to an observer, and
mirages, whereby an object looks like another one (say, of a different shape).
Such optical illusions are made possible thanks to the advent of metamaterials,
which are new kinds of composites designed using the concept of
transformational optics. Theoretical concepts introduced here are illustrated
by finite element computations.Comment: This is a book chapter. 22 pages, 7 figure