Image transfer properties by photonic crystal slab with negative refractive index

We have studied the properties of image transferred by photonic crystal (PhC) slab with negative refractive index n=−1 and confirmed the negative refractive phonomenon, but not found the saturated image properties as expected. It is found that real images will not be formed when the source distance larger than the thickness of PhC, and the transferred images are virtual images. Furthermore, comparing the quality of images transferred by a PhC slab and a cascaded stack of photonic crystal slab (CSPS), we found that the transferred images are distorted in both situations. The image resolution is good along the direction parallel to the slab interface, but bad along the direction normal to the slab interface. Simulation results show that the image formed by a CSPS is no better than a PhC slab.