Metamaterials: Negative refractive index in ... - Theory.nipne.ro

"Ideal lens" - simplified description of super-resolution(J. B. Pendry, D. R. Smith, Phys. Today,June 2004, pp. 37-43)(a) Image through classical lens, formed by the propagat<strong>in</strong>g field. The spatial resolution Δ is limited byk trM≈ ω 2 /c 2 , because k z= (ω 2 /c 2 –k trM2) 1/2 needs to be real to account for propagation Δ ≈ λ.(b) Attenuation of the evanescent field <strong>in</strong> the medium with n > 0 (classical lens <strong>in</strong> air or vacuum). The f<strong>in</strong>estructure of the object (small x, y) is revealed <strong>in</strong> the very large values of k trM(by the Fourier transformtheorem), mak<strong>in</strong>g the field to be evanescent (k trM> ω/c) k z= j(k trM– ω 2 /c 2 ) 1/2 . The <strong>in</strong>formation on thevery f<strong>in</strong>e structure of the object does not exist at the imag<strong>in</strong>e.(c) Image through the “ideal lens” obta<strong>in</strong>ed with propagat<strong>in</strong>g field Δ ≈ λ (identical to the case (a)).(d) Image through the “ideal lens” obta<strong>in</strong>ed with evanescent field amplified by the “ideal lens” Theoretical spatial resolution at the image: Δ ≈ 0 (near perfect, i.e., Δ ~ λ/100 - λ/1000).ASTiGMAT