Exciton polaritons in two-dimensional semiconductors inside microcavities are powerful platforms to explore hybrid light-matter quantum systems. Here, we study a macroscopic coherent population of the lowest energy state polaron-polaritons, which quasiparticles formed by dressing exciton particle-hole excitations surrounding electron gas. Using non-perturbative many-body theory describe exciton...

Exact results for the density of states and the ac conductivity of the spinless Holstein model at finite carrier density are obtained combining Lanczos and kernel polynomial methods.

We argue that the detailed analysis of the optical response in cuprate superconductors allows one to verify the magnetic scenario of superconductivity in cuprates. As for strong coupling charge carriers to antiferromagnetic spin fluctuations, the second derivative of optical conductivity should contain detectable singularities at 2D1Dspin , 4D , and 2D12Dspin , where D is the amplitude of the s...

We apply the time-dependent local density approximation (TDLDA) to calculate dipole excitations in small carbon molecules. Linear chains are found to have a strong low-frequency mode which varies with chain size as the classical resonance of a conducting needle; here the theory agrees well with observation on Cn molecules in the range n = 3 − 15. The lowest collective transition in rings occurs...

We calculate the third order nonlinear optical response in the Hubbard model within the spin density wave (SDW) mean field ansatz in which the gap is due to onsite Coulomb repulsion. We obtain closed-form analytical results in one dimension (1D) and two dimension (2D), which show that nonlinear optical response in SDW insulators in 2D is stronger than both 3D and 1D. We also calculate the two p...

We demonstrate resonant Faraday polarization rotation in plasmonic arrays of bimetallic nanoring resonators consisting of Au and Ni sections. This metamaterial design allows to optimize the trade-off between the enhancement of magneto-optical effects and plasmonic dissipation. Nickel sections corresponding to as little as ∼ 6% of the total surface of the metamaterial result in magneto-optically...

Bulk metal surfaces patterned with arrays of sub-wavelength surface features can couple incident light into localized plasmon modes, thereby modifying the intensity and phase of reflected light. Beyond previously reported applications to colour control, we report on the functionality of continuously metallic meta-surfaces for optical magnetic reflection, perfect absorption, and active photonic ...

We report an investigation on the optical properties of Cu3Ge thin films displaying very high conductivity, with thickness ranging from 200 to 2000 Å, deposited on Ge substrates. Reflectance, transmittance, and ellipsometric spectroscopy measurements were performed at room temperature in the 0.01–6.0, 0.01–0.6, and 1.4–5.0 eV energy range, respectively. The complex dielectric function, the opti...

The optical properties of plasmonic dipole and bowtie nanoantennas are investigated in detail using the Green's tensor technique. The influence of the geometrical parameters (antenna length, gap dimension and bow angle) on the antenna field enhancement and spectral response is discussed. Dipole and bowtie antennas confine the field in a volume well below the diffraction limit, defined by the ga...

We predict the strong enhancement in the photoabsorption of small Mg clusters in the region of 4-5 eV due to the resonant excitation of the plasmon oscillations of cluster electrons. The photoabsorption spectra for neutral Mg clusters consisting of up to N = 11 atoms have been calculated using ab initio framework based on the time dependent density functional theory (TDDFT). The nature of predi...