Cavity optomechanics in ultrastrong light matter coupling regime: Self-alignment and collective rotation mediated by Casimir torque

We theoretically consider an ensemble of quantum dimers placed inside an optical cavity. We predict two effects: first, an exchange of angular momentum between the dimers mediated by the emission and re-absorption of the cavity photons leads to the alignment of dimers. Furthermore, the optical angular momentum of the vacuum state of the chiral cavity is transferred to the ensemble of dimers which leads to the synchronous rotation of the dimers at certain levels of light-matter coupling strength.Comment: 14 pages, 8 figure

Resonant interaction of slow light solitons and dispersive waves in nonlinear chiral photonic waveguide

Publisher's version (útgefin grein)We study the structure of the elementary excitations and their propagation in chiral hybrid structure, comprising an array of two-level systems (TLSs) coupled to a one-dimensional photonic waveguide. The chirality is achieved via spin-locking effect, which in an ideal case gives perfect unidirectional excitation transport. We show that the application of transverse magnetic field which mixes the corresponding levels in TLS results in the emergence of the slow light mode in the photonic spectrum. Finally, we demonstrate the protocols of writing the signal to the slow light mode as well as reading it out with ultrashort optical pulses, which opens new avenues for the realization of optical memory devices based on chiral optical systems.The authors thank Dr MI Petrov for enlightening discussions. The work was by megagrant 14.Y26.31.0015 and Goszadanie no 3.261 4.2017/4.6 and 3.1365.2017/4.6 of the Ministry of Education and Science of Russian Federation. IVI and IAS acknowledges support from the Icelandic Research Fund, Grant No. 163082-051. IVI thanks Grant of President of Russian Federation МК-6248.2018.2, RFBR project 16-32-60123, and University of Iceland for hospitality. The work of AVY was financially supported by the Government of the Russian Federation (Grant 074-U01) through ITMO Fellowship scheme.Peer Reviewe

Floquet engineering of 2D materials

Publisher's version (útgefin grein)We demonstrate theoretically that the interaction of electrons in the 2D materials (gapped graphene and transition metal dichalchogenide monolayer) with a strong off-resonant electromagnetic field substantially renormalizes their band structure, including the band gaps and the spin-orbit splitting. Moreover, the renormalized electronic parameters drastically depend on the field polarization. Namely, a linearly polarized field always decreases the band gap (and, particularly, can turn the gap into zero), whereas a circularly polarized field breaks the equivalence of valleys in different points of the Brillouin zone and can both increase and decrease corresponding band gaps. As a consequence, the field can serve an effective tool to control spin and valley properties of the 2D materials and be potentially exploited in optoelectronic applications.The work was partially supported by Horizon2020 RISE project COEXAN, Russian Foundation for Basic Research (project 17-02-00053), and Ministry of Science and High Education of Russian Federation (projects 3.4573.2017/6.7, 3.8051.2017/8.9, 14.Y26.31.0015).Peer Reviewe

Scattering Suppression from Arbitrary Objects in Spatially-Dispersive Layered Metamaterials

Concealing objects by making them invisible to an external electromagnetic probe is coined by the term cloaking. Cloaking devices, having numerous potential applications, are still face challenges in realization, especially in the visible spectral range. In particular, inherent losses and extreme parameters of metamaterials required for the cloak implementation are the limiting factors. Here, we numerically demonstrate nearly perfect suppression of scattering from arbitrary shaped objects in spatially dispersive metamaterial acting as an alignment-free concealing cover. We consider a realization of a metamaterial as a metal-dielectric multilayer and demonstrate suppression of scattering from an arbitrary object in forward and backward directions with perfectly preserved wavefronts and less than 10% absolute intensity change, despite spatial dispersion effects present in the composite metamaterial. Beyond the usual scattering suppression applications, the proposed configuration may serve as a simple realisation of scattering-free detectors and sensors