Amplification of surface plasmon polaritons in the presence of nonlinearity and spectral signatures of threshold crossover

We describe effects of nonlinearity on propagation of surface plasmon polaritons (SPPs) at an interface between a metal and an amplifying medium of the externally pumped two-level atoms. Using Maxwell equations we derive the nonlinear dispersion law and demonstrate that, the nonlinear saturation of the linear gain leads to formation of stationary SPP modes with the intensities independent from the propagation distance. Transition to the regime of stationary propagation is similar to the threshold crossover in lasers and leads to narrowing of the SPP spectrum.Comment: http://www.opticsinfobase.org/ol/abstract.cfm?uri=ol-34-18-286

Non-minimal Einstein-Yang-Mills-Higgs theory: Associated, color and color-acoustic metrics for the Wu-Yang monopole model

We discuss a non-minimal Einstein-Yang-Mills-Higgs model with uniaxial anisotropy in the group space associated with the Higgs field. We apply this theory to the problem of propagation of color and color-acoustic waves in the gravitational background related to the non-minimal regular Wu-Yang monopole.Comment: 14 pages, no figure

Magnetic light

In this paper we report on the observation of novel and highly unusual magnetic state of light. It appears that in small holes light quanta behave as small magnets so that light propagation through such holes may be affected by magnetic field. When arrays of such holes are made, magnetic light of the individual holes forms novel and highly unusual two-dimensional magnetic light material. Magnetic light may soon become a great new tool for quantum communication and computing.Comment: Submitted to Phys.Rev.Lett., 3 figure

Frontal cortex functional activity modulation impact on the stereotypic, emotional and postural behavior in rats during the interictal period of pilocarpine-induced chronic epileptogenesis

The cholinergic mechanisms role determination in epileptogenesis attracts the attention of researchers. Pilocarpine administration in rats contributes to chronic form of epileptiform activity development characterized by the presence of a pronounced acute stage and an interictal period - free from behavioral convulsive reactions. We consider the most important feature of the pilocarpine-induced seizures interictal period might be the change of various forms of nonconvulsive behavior. Attempts to investigate the animals’ behavioral reactions details during the seizure-free interictal period, as well as to determine the mechanisms of similar types of behavior formation, are interesting. The purpose of the work is to investigate the motor, stereotypic and aggressive-defensive behavior of rats throughout the interictal period of pilocarpine-induced convulsive syndrome with a frontal cortex functional activity change. It was found that the severity of non-convulsive behavioral reactions in the interictal period during pilocarpine-induced chronic seizures is mostly determined by the frontal cortex functional state. At the same time, the frontal cortex hyperactivation is an important feature of pilocarpine-induced chronic epileptogenesis.  The authors proved that when the frontal cortex is activated in rats, there is an increase in horizontal and vertical motor activity, as well as the expressiveness of emotional reactions in the “open field” test and the strengthening of the aggressive-defensive behavior. In conditions of this part of the cortex selective destruction the opposite behavioral effects are noted which confirms the important role of the frontal cortex in the interictal non-convulsive behavior formation. Observed behavioral effects during the frontal cortex functional activity modulation, according to the authors, indicate the reasonability of regulatory influences searching aiming forward this brain part to activate complex mechanisms aimed to pilocarpine-induced chronic epileptiform activity elimination

Single-photon tunneling

Strong evidence of a single-photon tunneling effect, a direct analog of single-electron tunneling, has been obtained in the measurements of light tunneling through individual subwavelength pinholes in a thick gold film covered with a layer of polydiacetylene. The transmission of some pinholes reached saturation because of the optical nonlinearity of polydiacetylene at a very low light intensity of a few thousands photons per second. This result is explained theoretically in terms of "photon blockade", similar to the Coulomb blockade phenomenon observed in single-electron tunneling experiments. The single-photon tunneling effect may find many applications in the emerging fields of quantum communication and information processing.Comment: 4 pages, 4figure

Nonminimal isotropic cosmological model with Yang-Mills and Higgs fields

We establish a nonminimal Einstein-Yang-Mills-Higgs model, which contains six coupling parameters. First three parameters relate to the nonminimal coupling of non-Abelian gauge field and gravity field, two parameters describe the so-called derivative nonminimal coupling of scalar multiplet with gravity field, and the sixth parameter introduces the standard coupling of scalar field with Ricci scalar. The formulated six-parameter nonminimal Einstein-Yang-Mills-Higgs model is applied to cosmology. We show that there exists a unique exact cosmological solution of the de Sitter type for a special choice of the coupling parameters. The nonminimally extended Yang-Mills and Higgs equations are satisfied for arbitrary gauge and scalar fields, when the coupling parameters are specifically related to the curvature constant of the isotropic spacetime. Basing on this special exact solution we discuss the problem of a hidden anisotropy of the Yang-Mills field, and give an explicit example, when the nonminimal coupling effectively screens the anisotropy induced by the Yang-Mills field and thus restores the isotropy of the model.Comment: 15 pages, revised version accepted to Int. J. Mod. Phys. D, typos correcte

ДО 100-РІЧЧЯ ВІД ДНЯ СМЕРТІ ІВАНА ПУЛЮЯ

January 31, 2018 marked 100 years since the renowned scientist and patriot of Ukraine died – Ivan Puliui. It was him who built the first of the power stations in the Austro-Hungarian Empire, which worked on direct and alternating currents, studied cathode rays, which later became known as X-rays, was the inventor of devices that were awarded high prizes at international exhibitions. Together with Panteleimon Kulish, Ivan Nechuy-Levytskyі translated the Bible for the first time in Ukrainian. There are streets in the cities of Ukraine named in honor of Ivan Puliui, in particular, in Kyiv, Dnipropetrovsk, Lviv, Ternopil, Ivano-Frankivsk and Drohobych. Ternopil National Technical University is named after Ivan Puliui, where academic readings are held annually in honor of a great countryman.Fundamental research in physics and electrical engineering, popular scientific and journalistic works, memories of Ivan Puliui, world-class scientist, a man of solid moral convictions, a Great ukrainian, are relevant today.31 січня 2018 р. виповнилося 100 років від дня смерті відомого вченого і патріота України – Івана Пулюя. Це ж він збудував перші в Австро-Угорській імперії електростанції, які працювали на постійному та змінному струмах, досліджував катодні промені, які пізніше отримали назву рентгенівських, був винахідником приладів, які на міжнародних виставках відзначені високими нагородами. Це ж він разом із Пантелеймоном Кулішем, Іваном Нечуєм-Левицьким переклав вперше українською мовою Біблію. Ім’ям Івана Пулюя названо вулиці у містах України, зокрема у Києві, Дніпропетровську, Львові, Тернополі, Івано-Франківську та Дрогобичі. Тернопільський національний технічний університет носить ім’я Івана Пулюя, де щорічно проводяться наукові читання на честь великого земляка. Фундаментальні праці з фізики та електротехніки, науково-популярні, публіцистичні праці, спогади Івана Пулюя, світового рівня вченого, людини твердих моральних переконань, Великого українця, є актуальні і сьогодні

Circular Dichroism Enhancement in Plasmonic Nanorod Metamaterials

Optical activity is a fundamental phenomenon originating from the chiral nature of crystals and molecules. While intrinsic chiroptical responses of ordinary chiral materials to circularly polarized light are relatively weak, they can be enhanced by specially tailored nanostructures. Here, nanorod metamaterials, comprising a dense array of vertically aligned gold nanorods, is shown to provide significant enhancement of the circular dichroism response of an embedded material. A nanorod composite, acting as an artificial uniaxial crystal, is filled with chiral mercury sulfide nanocrystals embedded in a transparent polymer. The nanorod based metamaterial, being inherently achiral, enables optical activity enhancement or suppression. Unique properties of inherently achiral structures to tailor optical activities pave a way for flexible characterization of optical activity of molecules and nanocrystal-based compounds

Discrete structure of ultrathin dielectric films and their surface optical properties

The boundary problem of linear classical optics about the interaction of electromagnetic radiation with a thin dielectric film has been solved under explicit consideration of its discrete structure. The main attention has been paid to the investigation of the near-zone optical response of dielectrics. The laws of reflection and refraction for discrete structures in the case of a regular atomic distribution are studied and the structure of evanescent harmonics induced by an external plane wave near the surface is investigated in details. It is shown by means of analytical and numerical calculations that due to the existence of the evanescent harmonics the laws of reflection and refraction at the distances from the surface less than two interatomic distances are principally different from the Fresnel laws. From the practical point of view the results of this work might be useful for the near-field optical microscopy of ultrahigh resolution.Comment: 25 pages, 16 figures, LaTeX2.09, to be published in Phys.Rev.