Bulletin of the Russian Academy of Sciences: Physics最新文献

Under the conditions of the Markov approximation, a master kinetic equation is derived that describes the transfer of the state of a single-photon packet to the state of a solitary object, depending on the nature of the latter. A single-photon excitation is a broadband packet with a Gaussian frequency distribution (an information signal) that interacts nonresonantly with a selected high-Q cavity mode (an intermediary). The latter also interacts nonresonantly with an absorber whose natural frequency is resonant to the central frequency of the packet.

In metal-enhanced fluorescence of nanoparticles with rare earth ions, the number of photons and the rate of spontaneous transition are increased due to localized plasmon resonance. The model describes a nonmonotonic dependence of the quantum yield on the concentration of gold nanoparticles. The maximum is achieved due to the balance between the Purcell effect and optical absorption. These results are useful for the development of biological sensors with increased sensitivity.

To determine the optimal parameters of optical random number generation and mathematical postprocessing based on the lexicographic numbering of the noise of the optical random number generator, an integral indicator is proposed that combines the normalized values of three metrics: the arithmetic mean and the median percentage of successful NIST tests, as well as the proportion of results exceeding a given threshold.

In the electron paramagnetic resonance spectra of crystals of narrow-gap semiconductor Pb_1–xGd_xS ((3.2 times {{10}^{{ - 4}}} leqslant x leqslant 9.5 times {{10}^{{ - 3}}})), unusual changes in the shape of the lines of Gd³⁺((4{{f}^{7}},;,S = 7{text{/}}2)) centers were detected, which are caused by a change in the concentration of impurity gadolinium. The spectra of the studied crystals with increased gadolinium concentrations also show weaker additional lines of two types of new gadolinium centers with cubic symmetry of magnetic properties and with effective electron spins of (S = 7{text{/}}2) and (S = 5{text{/}}2.) Two possible explanations for the observed properties of the discovered paramagnetic centers were proposed.

The effect intermolecular interactions have on the conformational equilibria of several ethane-like compounds in a mixture of polyvinyl chloride and polyvinyl butyral is analyzed via Fourier-transform IR spectroscopy. The differences between enthalpies in the conformations of ethane-like compounds in a polymer mixture are determined, and the contributions from intermolecular interactions are estimated. The contributions from intermolecular interactions of ethane-like compounds, the polymer mixture, and the components of the mixture are compared.

It has been experimentally established that a mesogenic europium(III) β-diketonate complex fixed on a quartz substrate by drying a highly concentrated solution of the complex in carbon tetrachloride can reduce the luminescence brightness of Eu³⁺ ions during prolonged UV laser irradiation and spontaneously restore the initial luminescence parameters when kept in the dark for at least 22 h at room temperature.

In this paper, we studied the effect of near-ultraviolet laser radiation on the survival of bovine embryonic lung culture cells in the presence of antioxidants, namely vitamins E and C. We showed how cell viability changed at different wavelengths. We assessed how increasing the laser radiation power affected cell survival. In the presence of vitamins C (ascorbic acid) and E (tocopherol), a smaller decrease in cell survival was observed, indicating a relative balance between active oxygen species and antioxidants.

The derived master kinetic equation is used to determine the features of the nature of an isolated object, an absorber, on which the state of a broadband single-photon excitation is transferred. In the role of the absorber, a quantum oscillator or a two-level atom is considered. It is shown that, in the case of a nonresonant interaction between the packet and an intermediary, and between the intermediary and the absorber, the transfer of the state of a single-photon packet is possible if the absorber is a quantum oscillator. In the case where the transfer is to a two-level atom, the excitation transfer is only partial.

Glass–water and glass–air interfaces were visualized by second-harmonic generation microscopy. It was shown that the electrostatic surface potential can be determined from the recorded intensity of the signal from the glass surface in contact with solutions with different pH. Comparison of images of glass in contact with air and an aqueous solution at pH 2 hinted towards the similarity in the molecular structure of these interfaces.

A quantum memory scheme consisting of three optical resonators that form a photonic molecule with a programmable spectrum topology is studied. The dependence of the spectrum on the tuning parameters is analyzed to perform effective signal transfer to memory. The dynamics of the field in individual resonators is calculated for use in processing.