title: Quantum optical effective-medium theory for loss-compensated metamaterials.
abstract: A central aim in metamaterial research is to engineer subwavelength unit cells that give rise to desired effective-medium properties and parameters, such as a negative refractive index. Ideally one can disregard the details of the unit cell and employ the effective description instead. A popular strategy to compensate for the inevitable losses in metallic components of metamaterials is to add optical gain material. Here we study the quantum optics of such loss-compensated metamaterials at frequencies for which effective parameters can be unambiguously determined. We demonstrate that the usual effective parameters are insufficient to describe the propagation of quantum states of light. Furthermore, we propose a quantum optical effective-medium theory instead and show that it correctly predicts the properties of the light emerging from loss-compensated metamaterials.
authors.affiliation: Department of Photonics Engineering, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark and Department of Physics, Faculty of Basic Sciences, Shahrekord University, P.O. Box 115, Shahrekord 88186-34141, Iran and Department of Physics, Faculty of Science, University of Isfahan, Hezar-Jarib Street, 81746-73441 Isfahan, Iran.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Amooghorban
authors.affiliation: Department of Photonics Engineering, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
authors.forename: N Asger
authors.initials: NA
authors.lastname: Mortensen
authors.affiliation: Department of Photonics Engineering, Technical University of Denmark, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Martijn
authors.initials: M
authors.lastname: Wubs