Measurement of storage time, estimation of ion number and study of absorption line profile in a Paul trap

Europium (Eu⁺) ions were confined in a Paul trap and detected by non-destructive method. Storage time of Eu⁺ ions achieved in vacuum was improved by orders of magnitude employing buffer gas cooling. The experimentally detected signal was fitted to the ion response signal and the total number of ions trapped was estimated. It is found that the peak signal amplitude as well as the product of FWHM and the peak signal amplitude is proportional to the total number of trapped ions. The trapped ion secular frequency was swept at different rates and its effect on the absorption line profile was studied both experimentally and theoretically.     

Parametric scattering in a system of quasi-two-dimensional exciton polaritons under photoexcitation near the bottom of the upper polariton branch

Cascade processes of exciton-polariton scattering in a planar semiconductor microcavity taking place under resonance pumping near the bottom of the upper polariton branch are studied theoretically. When the conservation laws allow the decay of the resonantly excited state into two modes that belong to different (the upper and lower) polariton branches, the distribution of scattering directions has the general shape of two rings that correspond to the cross sections of the lower and upper polariton dispersion surfaces by constantenergy planes. Due to the interactions between the particles, instability develops in the system of scattered modes, which is accompanied by marked inhomogeneities in the distribution of the cavity photoluminescence signal. Self-organization in such a system leads to the appearance of solutions of an essentially collective nature. As the critical (threshold) pump power is attained, macroscopic occupancy of a predominant signal mode near the bottom of the lower polariton branch sets in. The characteristics of the signal for different powers and optical polarizations of the pump are analyzed.     

Optical fano resonances in photonic crystal slabs near diffraction threshold anomalies

Optical Fano resonances due to resonant eigenmodes in a layered periodically-modulated structure (photonic crystal slab) are investigated theoretically. The special attention is focused on the behavior of the resonances near a diffraction threshold. A new formulation of the resonant mode approximation for the optical scattering matrix near the diffraction threshold anomalies is proposed.     

Polarization multistability of cavity polaritons

New effects of polarization multistability and polarization hysteresis in a coherently driven polariton system in a semiconductor microcavity are predicted and theoretically analyzed. The multistability arises due to polarization-dependent polariton-polariton interactions and can be revealed in polarization resolved photoluminescence experiments. The pumping power required to observe this effect is 4 orders of magnitude lower than the characteristic pumping power in conventional bistable optical systems.     

Correction: Dermatan sulfate in tunicate phylogeny: Order-specific sulfation pattern and the effect of [→4IdoA(2-Sulfate)β-1→3GalNAc(4-Sulfate)β-1→] motifs in dermatan sulfate on heparin cofactor II activity

After the publication of the work entitled "Dermatan sulfate in tunicate phylogeny: Order-specific sulfation pattern and the effect of [→4IdoA(2-Sulfate)β-1→3GalNAc(4-Sulfate)β-1→] motifs in dermatan sulfate on heparin cofactor II activity", by Kozlowski et al., BMC Biochemistry 2011, 12:29, we found that the legends to Figures 2 to 5 contain serious mistakes that compromise the comprehension of the work. This correction article contains the correct text of the legends to Figures 2 to 5.     

Effective electromagnetic response of nanostructured metal-dielectric metamaterials

The optical properties of metamaterial layers have been analyzed by the scattering matrix method. The properties of effective ɛ and μ, reconstructed from the transmittance and reflectance of metamaterial layers of finite thickness using the inverse Fresnel formulas, are discussed. It is shown that the optical response of nanostructured metal-dielectric metamaterials is strongly nonlocal and dissipative. Original Russian Text ? S.G. Tikhodeev, 2009, published in Izvestiya Rossiiskoi Akademii Nauk. Seriya Fizicheskaya, 2009, Vol. 73, No. 1, pp. 95–97.     

Dielectric enhancement of excitons in semiconducting quantum wires

The energy of the exciton ground state in a semiconducting cylindrical quantum wire surrounded by a dielectric has been calculated using a variational technique accounting for the effect of dielectric enhancement. The effect of dielectric enhancement in such a system has been clearly demonstrated. Exciton parameters have been calculated for an intercalated leadiodide-based quasi-one-dimensional semiconductor and GaAs wires in asbestos nanotubes. Zh. éksp. Teor. Fiz. 111, 274–282 (January 1997)