Figure 1

(Color online) A flat slab of left-handed material can act as a lens forming a perfect 3D image of any object located at a distance less than the slab thickness from the surface.Reuse & Permissions

Figure 2

(Color online) Resonant transparency of a perforated metal film. A periodically modified (perforated or corrugated) optically thick metal film becomes essentially transparent for certain resonant frequencies or angles of incidence.Reuse & Permissions

Figure 3

(Color online) The total absorption of electromagnetic waves in (a)–(c) optics and (d)–(f) plasma physics. Strikingly, even though elements (a), (b) or (d), (e) act separately as very good mirrors, their combination can absorb all the incident radiation (c), (f).Reuse & Permissions

Figure 4

(Color online) Resonant wave transmission through a 1D random dielectric sample. The spatial distributions of the intensity of the resonant (central) and nonresonant (edge) waves are depicted on the top of the sample, which is displayed schematically.Reuse & Permissions

Figure 5

(Color online) Examples of classical and quantum open quasi-1D resonators. (a) A waveguide segment (cavity) is surrounded by Bragg-reflecting or subcritical segments (acting as barriers). The field inside the resonator can interact with an external wave field through nonpropagating evanescent modes in the barriers. A 3D generalization of the top system can be a cavity inside a photonic crystal in the frequency gap. (b) Any potential well can represent a quantum resonator. Open resonators are surrounded by finite-width barriers. An incident particle can effectively tunnel through both energy barriers when its energy coincides with one of the energy levels in the cavity (14). A characteristic quasimode wave function is depicted at the bottom.Reuse & Permissions

Figure 6

(Color online) Near-resonant transmission of an incident wave through two coupled open resonators at different values of $qQ$. The normalized (i.e., multiplied by the factor $2Q^{-1}$) absolute values of the field amplitudes in two resonators, (a) $\mid {\tilde{A}}_{\mathrm{out}}\mid$ and (b) $\mid {\tilde{A}}_{\mathrm{in}}\mid$, are shown. In the dissipationless case ($Q_{\mathrm{diss}}^{-1}=0$, $Q=Q_{\mathrm{leak}}$), the transmission coefficient of the system is given by $T=\mid {\tilde{A}}_{\mathrm{out}}{\mid }^2$.Reuse & Permissions

Figure 7

(Color online) Schematic diagrams of surface plasmon-polariton (PP) resonators, their interaction with incident waves, and the corresponding resonators parameters. (a) A vacuum/metal interface supports plasmon modes localized in the $z$ direction and reflects propagating waves. Propagating and evanescent waves do not interact with each other, and, therefore, there is no energy leakage from the PP resonator. (b) A metal film represents a system of two PP resonators coupled by their fields. A diffraction grating [or total internal reflection (TIR) interface, Fig. 3] can transform a propagating wave into an evanescent wave and vice versa, thereby making the PP resonators open, $Q_{\mathrm{leak}}^{-1}\ne 0$. Resonant total transparency can be achieved when the dissipation is negligible, whereas the coupling is strong enough; cf. Figs. 2, 6. (c) In the critical-coupling regime, all of the incident wave is absorbed by the metal or plasma due to intrinsic dissipation, cf. Fig. 3. (d) A slab of an ideal LHM also represents two coupled PP resonators. There are two essential distinctions as compared to metal films: (i) A LHM is transparent for propagating fields and (ii) plasmon polaritons are always in resonance with evanescent fields from the source. The latter means that the PP field distribution corresponds to the $\nu =1$ point in Fig. 6, and the evanescent field energy is concentrated at the output surface in the dissipationless case. As a result, both propagating and evanescent fields form an exact copy of the source field in the focal point; cf. Fig. 1.Reuse & Permissions

Figure 8

(Color online) The sample in Fig. 4 is now “cut” into three separate segments that are considered independently. It can be seen that while the right- and left-side segments are practically opaque due to Anderson localization, the central part (where a large energy concentration has been observed in resonance) happens to be almost transparent for the resonant frequency. This provides the standard barrier-cavity-barrier resonator structure, which explains the resonant features of the sample at a given frequency.Reuse & Permissions

Figure 9

(Color online) Spectra of (a) the transmittance $T$ and (b) the reflectance $R$ for various values of the dissipation rate $Q_{\mathrm{diss}}$ in a random dielectric sample. Although the dissipation is extremely small, peaks of resonant transmittance disappear rapidly when the dissipation increases. At the same time, peaks in $1-R$ become sharply pronounced and become even more informative than in the dissipationless case. Resonances with $R=T=0$ evidence the critical-coupling regime.Reuse & Permissions