Electromagnetic waves focused by a negative-index planar lens

Abstract

We demonstrate that negative refraction occurs for both cw and pulsed electromagnetic waves when traversing from a "right-handed" (index > 0) to a "left-handed" (index < 0) material (LHM) which has causal dispersive intrinsic properties. We also demonstrate that a divergent line source spaced a distance H in front of a planar LHM slab and excited by either an impulse cw or a Gaussian frequency pulse is imaged at a distance H away, inside the LHM, and at H to the other side of the slab. The image size is approximately lambda consistent with limitations dictated by wave optics. We find no evidence of evanescent mode amplification. The studies were performed using numerical experiments with finite difference time domain solutions and incorporating a causal Lorentzian form for the frequency-dependent material properties.

Analysis of wave propagation in a two-dimensional photonic crystal with negative index of refraction: plane wave decomposition of the Bloch modes

“…3(c) we can see that the modulated phase fronts have a positive slope, in clear contrast to the diagram shown in Ref. 20 for a LHM. If we consider the main phase front (this concept will be analyzed more in detail in the next section), highlighted with a dashed line in Figs.…”

“…We present the results as in Ref. 20: a diagram that represents the electric field amplitude with the simulation time in the vertical direction (in ct/a units, t being the absolute time) and the space (monitor position) in the horizontal direction. This kind of diagram allows a straightforward visualization of the phase fronts, as shown in Fig.…”

Negative Refraction by Photonic Crystal

“…Experimental observation of negative refraction in meta-materials is verified by Shelby et al [5]. Recently negative refraction has been the subject of considerable interest which may provide the possibility of a variety of novel applications of very interesting new phenomena like the superlens effect [6][7][8][9][10]. A negative refractive index arises in meta-materials that have simultaneous negative permittivity ε and permeability µ, where in homogeneities are much smaller than the wavelength of the incoming radiation and it has been demonstrated at microwave wavelengths [11][12][13].…”

Observation of negative refraction and negative phase velocity in left-handed metamaterials

“…[10][11][12] However, reversal of phase velocity can also be used as an indication of LH behavior. [12][13][14] In this letter, we present direct experimental evidence that both the phase velocity and the refractive index is negative within the LH pass band of a CMM.…”