Manipulating sources using transformation optics with 'folded geometry'

Using the idea of transformation optics, we propose a way to annihilate or re-shape the radiation field of a source through remote manipulation. The manipulation is enabled by metamaterials that correspond to space folding coordinate transformations. It is shown that when two coherent sources with equal magnitudes and opposite phases are placed at equivalent positions in normal and folded spaces, they 'annihilate' each other optically. The folded space also gives the possibility of creating complex multipole sources by placing simple sources separately in normal and folded spaces. These ideas may find applications in areas such as active noise control and antenna design techniques.