title: Optimized effective permittivity to improve imaging resolution of multilayered structures in the infrared.
abstract: Two periodic structures with different effective impedances, both comprising alternate layers of a positive and a negative permittivity material, are considered in the infrared. We find that the Fabry-Perot resonance effect periodically influences the sharpness of subwavelength focusing as the total thicknesses of the two structures increase, especially for the impedance-matched structure. On the basis of the improved multilayered structures, we design an optimized structure (i.e., the effective impedance is chosen between 0 and 1) for which a higher resolution less than lambda/12 (lambda is the wavelength in the air) can be obtained through weighing the advantages and disadvantages of the two different multilayered structures and choosing appropriate surface terminations.
authors.affiliation: Department of Physics and Institute of Condensed Matter Physics, Hangzhou Normal University,Hangzhou 310012, China. xuanli@kth.se
authors.forename: Xuan
authors.initials: X
authors.lastname: Li
authors.forename: Fei
authors.initials: F
authors.lastname: Zhuang
authors.forename: Christian V
authors.initials: CV
authors.lastname: Köhnenkamp