Manipulating the field distribution via optical transformation

Using the coordinate transformation theory, we propose a way to control the field distribution of electromagnetic wave in a waveguide filling with properly designed transformation media. The results show that the field distribution of the electromagnetic wave can be compressed and amplified in both longitudinal and transverse direction. A realizable layered waveguide based on the discrete optical transformation is also designed to manipulate the field distribution of the electromagnetic wave. Potential applications, i.e., turn a narrow (wide) slit into a large (small) window, are investigated in detail.