Focusing properties of a spherical perfect lens with eccentric deformations
A spherical perfect lens made of a shell of negative refractive index material is known not only for its subwavelength resolution of images but also for the magnification of the near field image due to its curved geometry. We investigate the effects on the image resolution arising from geometric deformations of the spherical perfect lens, whereby an eccentricity in the spherical shell is introduced. Using a first order perturbative method valid for small deformations in the near field (quasi static) limit, we find that small deformations ~1% of the inner radius of the shell) appear to affect the strength of the multipoles in the image by only few percent and do not have any drastic effects. Our results indicate that near field imaging can be robust against small geometric imperfections in these imaging devices, which is expected to be highly encouraging to nanoscale/microscale design in optical engineering.