IEEE Journal of Selected Topics in Quantum Electronics
Photonic Metamaterials: Magnetism at Optical Frequencies
Stefan Lindén, Christian Enkrich, Gunnar Dolling, Matthias W. Klein, Jiangfeng Zhou, Thomas Koschny, Costas M. Soukoulis, Sven Burger, Frank Schmidt, Martin Wegener
Photonic metamaterials are man-made materials with "lattice constants" smaller than the wavelength of light. Tailoring the properties of their functional building blocks (atoms) allows one to go beyond the possibilities of usual materials. For example, magnetic dipole moments at optical frequencies (mune1) become possible. This aspect substantially enriches the possibilities of optics and photonics and forms the basis for the so-called negative-index metamaterials. Here, we describe the underlying physics and review the recent progress in this rapidly emerging field
Photonic metamaterials are man-made materials with "lattice constants" smaller than the wavelength of light. Tailoring the properties of their functional building blocks (atoms) allows one to go beyond the possibilities of usual materials. For example, magnetic dipole moments at optical frequencies (mune1) become possible. This aspect substantially enriches the possibilities of optics and photonics and forms the basis for the so-called negative-index metamaterials. Here, we describe the underlying physics and review the recent progress in this rapidly emerging field
Metamaterials are artificial materials with exotic physical, chemical and optical properties not found in natural materials. In the past decade they have attracted monumental attention from the scientific community owing to their applications ranging from physics to engineering. However, the conventional solid-state metamaterial platforms suffer from inevitable optical loss, defects which severely curtain their application at few-photon level. The quest for quantum optical applications with metamaterial-based technologies has stimulated researchers to engineer novel lossless materials and construct new platforms. Recently, by integrating two important and timely realms of science − trapped atom physics and metamaterials −, we proposed and theoretically demonstrated a topologically reconfigurable and lossless quantum metamaterial. The atomic lattice quantum metamaterial is immune to aforementioned critical challenges and can be employed at a single-photon level. Moreover, in stark contrast to conventional solid-state platforms, optical lattices provide the necessary freedom to precisely localize (within few nanometer of uncertainty) a probe atom, inside the atomic lattice quantum metamaterial to harness its exotic optical properties. In addition to its aforementioned novel characteristics, our atomic lattice quantum metamaterial offers a unique degree of freedom, namely all-optical control on ultrafast time scales over the photonic topological transition of isofrequency contours using weak fields, not possible with previous solid-state platforms. In this work, we leverage the tools, techniques, scientific advances in the field of atomic, molecular and optical physics, integrated with the concepts used in metamaterials to propose and theoretically demonstrate a novel platform towards quantum metamaterial with novel functionalities by bringing together the best of two worlds.
We propose novel quantum antennas and metamaterials with a strong magnetic response at optical frequencies. Our design is based on the arrangement of natural quantum emitters with only electric dipole transition moments at distances smaller than a wavelength of light but much larger than their physical size. In particular, we show that an atomic dimer can serve as a magnetic antenna at its antisymmetric mode to enhance the decay rate of a magnetic transition in its vicinity by several orders of magnitude. Furthermore, we study metasurfaces composed of atomic bilayers with and without cavities and show that they can fully reflect the electric and magnetic fields of light, thus, forming nearly perfect electric or magnetic mirrors. The proposed metamaterials will embody the intrinsic quantum functionalities of natural emitters such as atoms, ions, color center, or molecules and can be fabricated with available state-of-the-art technologies, promising several applications both in classical optics and quantum engineering.
The topic of electromagnetic propagation in dielectric media has been enlivened in the past decade by a number of remarkable experimental results showing the technical ability to control the speed of light propagation in exotic ways. Light pulses have been observed travelling faster than c, or slowed by many orders of magnitude, or even stopped completely. All of thcse results require careful interpretation, and a variety of theoretical interpretations have been proposed and/or published, not all agreeing with each other. At the same time, in a lower frequency range than optical, rapid development of so-called meta-materials or double-negative materials has occurred. These materials are characterized by electric permittivity and magnetic permeability with very unconventional values, both quantities negative in some cases. Such unusual properties, especially when leading to a negative value for the group velocity, clearly indicate another possibility for control of light. Such materials are being improved rapidly, but independent of their implementation in the laboratory, their theoretical properties have led to dramatic predictions such as the existence of a perfect lens, Le., a finite lens (actually even planar-flat rather than parabolic) that can deliver an ideally sharp focus unaffected by diffractive effects. There are strong contentions currently being published that such predictions are erroneous
In this paper we review our recent works in developing photonic crystals and nanophotonic structures for the control of light. We show that dynamic crystal structures, in which the refractive index of the material is modulated by a small extent while a photon pulse is in the crystal, can be used to stop, store and even time-reverse light pulses [ 1][ 2][ 3]. We also show that by incorporating magneto-optical effects into the crystal structures, the reciprocity of light can be broken, resulting in uni-directional devices that are extremely compact [ 4]. And finally, by exploiting sub-wavelength electromagnetic resonances in meta structures, new meta-materials can be created. These materials feature frequency-independent refractive index that is controlled by geometry and can be arbitrarily large [ 5]. Such materials can be of importance for integrated optics and image sensing applications.
By coupling controllable quantum systems into larger structures we introduce the concept of a quantum metamaterial. Conventional meta-materials represent one of the most important frontiers in optical design, with applications in diverse fields ranging from medicine to aerospace. Up until now however, metamaterials have themselves been classical structures and interact only with the classical properties of light. Here we describe a class of dynamic metamaterials, based on the quantum properties of coupled atom-cavity arrays, which are intrinsically lossless, reconfigurable, and operate fundamentally at the quantum level. We show how this new class of metamaterial could be used to create a reconfigurable quantum superlens possessing a negative index gradient for single photon imaging. With the inherent features of quantum superposition and entanglement of metamaterial properties, this new class of dynamic quantum metamaterial, opens a new vista for quantum science and technology.