Metamaterials have introduced a whole new world of unusual materials with functionalities that cannot be attained in naturally occurring material systems by mimicking and controlling the natural phenomena at subwavelength scales. However, the inherent absorption losses pose fundamental challenge to the most fascinating applications of metamaterials. Based on a novel plasmon injection (PI or )-scheme, we propose a coherent optical amplification technique to compensate losses in metamaterials. Although the proof of concept device here operates under normal incidence only, our proposed scheme can be generalized to arbitrary form of incident waves. The -scheme is fundamentally different than major optical amplification schemes. It does not require gain medium, interaction with phonons, or any nonlinear medium. The -scheme allows for loss-free metamaterials. It is ideally suited for mitigating losses in metamaterials operating in the visible spectrum and is scalable to other optical frequencies. These findings open the possibility of reviving the early dreams of making "magical" metamaterials from scratch. PACS numbers:Metamaterials have led to previously unthought-of applications such as flat lens [1], perfect lens [2], hyperlens [3][4][5], ultimate illusion optics [6][7][8], perfect absorber [9,10], optical analog simulators [11,12], metaspacers [13], and many others. Despite tremendous progress in theory and experimental realizations, the major current challenges seem to further delay the metamaterial era to come. For instance, achieving full isotropy, feasible fabrication methods, broad bandwidth, and compensation of dissipative losses especially at optical frequencies are among the challenges yet to be solved [14,15]. Perhaps, the most critical of all is how to avoid optical losses -especially in large-volume structures. The performance of devices utilizing metamaterials dramatically degrades at optical frequencies due to significant ohmic losses arising from the metallic constituents. The strategies proposed to mitigate the losses include passive reduction and active compensation schemes. Avoiding sharp edges [16], reducing skin depths [16][17][18], and classical analog of electromagnetically induced transparency are proposed as passive loss minimization techniques [19,20]. Constitutive materials such as dielectrics [21], nitrides [22], oxides [23], graphene [24], and superconductors [24-30] have also been explored for possible alternatives to lossy conductors. However, none of these materials have so far shown to outperform the performance of high-conductivity metals at room temperature [31,32]. Active compensation of losses using gain medium has been emerged as the most promising strategy to avoid the deleterious impacts of losses on metamaterial devices. Optically pumped semiconductor quantum dots and quantum wells incorporated in planar metamaterials have been experimentally shown to compensate the losses to some extent [33][34][35][36][37][38]. A remarkable improvement in the figure of merit (FOM) of a ...

Near-field optics and superlenses for imaging beyond Abbe's diffraction limit are reviewed. A comprehensive and contemporary background is given on scanning near-field microscopy and superlensing. Attention is brought to recent research leveraging scanning near-field optical microscopy with superlenses for new nano-imaging capabilities. Future research directions are explored for realizing the goal of low-cost and high-performance sub-diffraction-limited imaging systems. © 2016 Author(s)

In this paper, the optical properties and imaging performance of a non-ideal Pendry's negative index flat lens with a practical value for loss are studied. Analytical calculations of the optical properties of the lens are performed, and those results are used to further study the lens and corresponding imaging system numerically. An inverse filter emulating the plasmon injection scheme for loss compensation in negative index metamaterials is applied to the results from the imaging system, resulting in a perfect reconstruction of a previously unresolved image that demonstrates sub-diffraction-limited resolution.

We propose an alternative class of magneto-optical metamaterials offering enhanced angle of rotation in polarization compared to pure magneto-optical materials. In this approach, the permittivity tensor of a magneto-optical material is tailored by embedded wire meshes. We show that the angle of rotation in the magneto-optical metamaterial can be enhanced up to 9 times compared to pure magneto-optical material alone, while the polarization extinction ratio remains below −20dB over more than 2 THz bandwidth and the attenuation coefficient is approximately 1.5dB μm−1.

We propose a scheme for the distillation of partially entangled two-photon Bell and three-photon W states using metamaterials. The distillation of partially entangled Bell states is achieved by using two metamaterials with polarization dependence, one of which is rotated by π/2 around the direction of propagation of the photons. On the other hand, the distillation of three-photon W states is achieved by using one polarization dependent metamaterial and two polarization independent metamaterials. Upon transmission of the photons of the partially entangled states through the metamaterials the entanglement of the states increases and they become distilled. This work opens up new directions in quantum optical state engineering by showing how metamaterials can be used to carry out a quantum information processing task.