Van der Waals interaction and spontaneous decay of an excited atom in a superlens-type geometry

Within the framework of macroscopic quantum electrodynamics, the resonant van der Waals potential experienced by an excited two-level atom near a planar magneto-electric two-layer system consisting of a slab of left-handed material and a perfect mirror is studied. It is shown that disregarding of material absorption leads to unphysical results, with divergent values for the potential away from the surface. Under appropriate conditions, the setup is found to feature a barrier near the surface which can be employed to levitate particles or used as a trapping or cooling mechanism. Finally, the problem of spontaneous decay [J. K\"{a}stel and M. Fleischhauer, Phys. Rev. A \textbf{68}, 011804(R) (2005)] is revisited. Disregarding of absorption is shown to drastically falsify the dependence on the atomic position of the decay rate.Comment: 10 Pages, 6 figure

Comparison of Quantum and Classical Local-field Effects on Two-Level Atoms in a Dielectric

The macroscopic quantum theory of the electromagnetic field in a dielectric medium interacting with a dense collection of embedded two-level atoms fails to reproduce a result that is obtained from an application of the classical Lorentz local-field condition. Specifically, macroscopic quantum electrodynamics predicts that the Lorentz redshift of the resonance frequency of the atoms will be enhanced by a factor of the refractive index n of the host medium. However, an enhancement factor of (n*n+2)/3 is derived using the Bloembergen procedure in which the classical Lorentz local-field condition is applied to the optical Bloch equations. Both derivations are short and uncomplicated and are based on well-established physical theories, yet lead to contradictory results. Microscopic quantum electrodynamics confirms the classical local-field-based results. Then the application of macroscopic quantum electrodynamic theory to embedded atoms is proved false by a specific example in which both the correspondence principle and microscopic theory of quantum electrodynamics are violated.Comment: Published version with rewritten abstract and introductio

Electromagnetic-field quantization and spontaneous decay in left-handed media

We present a quantization scheme for the electromagnetic field interacting with atomic systems in the presence of dispersing and absorbing magnetodielectric media, including left-handed material having negative real part of the refractive index. The theory is applied to the spontaneous decay of a two-level atom at the center of a spherical free-space cavity surrounded by magnetodielectric matter of overlapping band-gap zones. Results for both big and small cavities are presented, and the problem of local-field corrections within the real-cavity model is addressed.Comment: 15 pages, 5 figures, RevTe

Experimental demonstration of the microscopic origin of circular dichroism in two-dimensional metamaterials

Optical activity and circular dichroism are fascinating physical phenomena originating from the interaction of light with chiral molecules or other nano objects lacking mirror symmetries in three-dimensional (3D) space. While chiral optical properties are weak in most of naturally occurring materials, they can be engineered and significantly enhanced in synthetic optical media known as chiral metamaterials, where the spatial symmetry of their building blocks is broken on a nanoscale. Although originally discovered in 3D structures, circular dichroism can also emerge in a two-dimensional (2D) metasurface. The origin of the resulting circular dichroism is rather subtle, and is related to non-radiative (Ohmic) dissipation of the constituent metamolecules. Because such dissipation occurs on a nanoscale, this effect has never been experimentally probed and visualized. Using a suite of recently developed nanoscale-measurement tools, we establish that the circular dichroism in a nanostructured metasurface occurs due to handedness-dependent Ohmic heating.ope

Ray Optics at a Deep-Subwavelength Scale: A Transformation Optics Approach

We present a transformation optics approach for molding the light flow at the deep-subwavelength scale, using metamaterials with uniquely designed dispersion. By conformal transformation of the electromagnetic space, we develop a methodology for realizing subwavelength ray optics with curved ray trajectories. This enables deep-subwavelength-scale beams to flow through two- or three-dimensional spaces