Imaging properties of an annular photonic crystal slab for both TM-polarization andTE-polarization

Abstract

The imaging behaviors for two kinds of polarized waves found by using a two-dimensionalannular photonic crystal flat lens are theoretically investigated. For the TE-polarization,subwavelength imaging due to a negative refraction effect is obtained and the focal lengthcan be adjusted by changing the lens thickness. In contrast, for the TM-polarization,because the resulting optical field distribution behind the slab resembles a triple pointsource due to the effect of channeling, the light can focus again due to the interferenceeffect. Most importantly, using the proper annular photonic crystal lens, the image of anunpolarized wave point source can be realized. These results show that the negativerefraction is not the one and only mechanism of imaging by a photonic crystal lens.