Negative-Index Metamaterials: Second-Harmonic Generation, Manley-Rowe Relations and Parametric Amplification

Second harmonic generation and optical parametric amplification in negative-index metamaterials (NIMs) are studied. The opposite directions of the wave vector and the Poynting vector in NIMs results in a "backward" phase-matching condition, causing significant changes in the Manley-Rowe relations and spatial distributions of the coupled field intensities. It is shown that absorption in NIMs can be compensated by backward optical parametric amplification. The possibility of distributed-feedback parametric oscillation with no cavity has been demonstrated. The feasibility of the generation of entangled pairs of left- and right-handed counter-propagating photons is discussed.Comment: 7 pages, 6 figure

Nonlinear surface waves in left-handed materials

We study both linear and nonlinear surface waves localized at the interface separating a left-handed medium (i.e. the medium with both negative dielectric permittivity and negative magnetic permeability) and a conventional (or right-handed) dielectric medium. We demonstrate that the interface can support both TE- and TM-polarized surface waves - surface polaritons, and we study their properties. We describe the intensity-dependent properties of nonlinear surface waves in three different cases, i.e. when both the LH and RH media are nonlinear and when either of the media is nonlinear. In the case when both media are nonlinear, we find two types of nonlinear surface waves, one with the maximum amplitude at the interface, and the other one with two humps. In the case when one medium is nonlinear, only one type of surface wave exists, which has the maximum electric field at the interface, unlike waves in right-handed materials where the surface-wave maximum is usually shifted into a self-focussing nonlinear medium. We discus the possibility of tuning the wave group velocity in both the linear and nonlinear cases, and show that group-velocity dispersion, which leads to pulse broadening, can be balanced by the nonlinearity of the media, so resulting in soliton propagation.Comment: 9 pages, 10 figure

Solitary wave solution to the generalized nonlinear Schrodinger equation for dispersive permittivity and permeability

We present a solitary wave solution of the generalized nonlinear Schrodinger equation for dispersive permittivity and permeability using a scaling transformation and coupled amplitude-phase formulation. We have considered the third-order dispersion effect (TOD) into our model and show that soliton shift may be suppressed in a negative index material by a judicious choice of the TOD and self-steepening parameter.Comment: 6 page

Small-Size Resonant Photoacoustic Cell of Inclined Geometry for Gas Detection

A photoacoustic cell intended for laser detection of trace gases is represented. The cell is adapted so as to enhance the gas-detection performance and, simultaneously, to reduce the cell size. The cell design provides an efficient cancellation of the window background (a parasite response due to absorption of laser beam in the cell windows) and acoustic isolation from the environment for an acoustic resonance of the cell. The useful photoacoustic response from a detected gas, window background and noise are analyzed in demonstration experiments as functions of the modulation frequency for a prototype cell with the internal volume ~ 0.5 cm^3. The minimal detectable absorption for the prototype is estimated to be ~ 1.2 10^{-8} cm^{-1} W Hz^{-1/2}.Comment: 11 pages, 5 figure

Interface electronic states and boundary conditions for envelope functions

The envelope-function method with generalized boundary conditions is applied to the description of localized and resonant interface states. A complete set of phenomenological conditions which restrict the form of connection rules for envelope functions is derived using the Hermiticity and symmetry requirements. Empirical coefficients in the connection rules play role of material parameters which characterize an internal structure of every particular heterointerface. As an illustration we present the derivation of the most general connection rules for the one-band effective mass and 4-band Kane models. The conditions for the existence of Tamm-like localized interface states are established. It is shown that a nontrivial form of the connection rules can also result in the formation of resonant states. The most transparent manifestation of such states is the resonant tunneling through a single-barrier heterostructure.Comment: RevTeX4, 11 pages, 5 eps figures, submitted to Phys.Rev.

Resonant nonlinear optics of backward waves in negative-index metamaterials

The extraordinary properties of resonant four-wave mixing of backward waves in doped negative-index materials are investigated. The feasibility of independent engineering of negative refractive index and nonlinear optical response as well as quantum control of the nonlinear propagation process in such composites is shown due to the coherent energy transfer from the control to the signal field. Laser-induced transparency, quantum switching, frequency-tunable narrow-band filtering, amplification, and realizing a miniature mirrorless optical parametric generator of the entangled backward and ordinary waves are among the possible applications of the investigated processes.Comment: 10 pages, 9 figure

Перспективы обеспечения продовольственной безопасности Российской Федерации

In conditions of globalization of all spheres of human life, an open national food system can not develop without taking into account the global trends. The dynamics of indicators of development of the world and the Russian food systems is considered in the article, the main tendencies of development of the Russian food system are revealed comparing to global indicators and can be characterized as negative. In the country there is a constant reduction of population, especially rural, that means a reduction in labor resources and a reduction in the food demand. On the other hand, the clear trend is the growth of food exports. To further development of the export potential of Russian producers, it is necessary to improve agricultural policy, especially in terms of creating conditions for competing food both on the domestic and foreign markets, of creating agricultural innovative sys tem, and to develop rural areas. In Russia, there are opportunities not only to achieve the parameters of the Food Security Doctrine (for which indicators for 6 food groups out of 10 have been achieved), but also to increase ex ports of products.В условиях глобализации всех сфер человеческой жизни открытая национальная про довольственная система не может развиваться без учета общемировых тенденций. В статье рас смотрена динамика показателей развития мировой и российской продовольственных систем, выявле ны основные тенденции развития российской продовольственной системы, которые на фоне общеми ровых показателей можно охарактеризовать скорее негативно. В стране происходит постоянное со кращение численности населения, особенно сельского, что означает сокращение трудовых ресурсов и сужение спроса на продукты питания. С другой стороны, отчетливой тенденцией является рост экс порта продуктов питания. Для дальнейшего развития экспортного потенциала российских произво дителей необходимо совершенствовать аграрную политику, особенно в части создания условий для конкурирования отечественного продовольствия как на внутреннем, так и на внешних рынках, для создания инновационной аграрной системы, для развития сельской местности. В России имеются возможности не только для достижения параметров Доктрины продовольственной безопасности (по которой достигнуты показатели по 6 продовольственным группам из 10), но и увеличения экспорта продукции

A New Glance at Old Samples: Remains of Freshwater Invertebrates Associated with Mummified Carcasses of Large Quaternary Mammals

© 2020, Pleiades Publishing, Inc. Abstract—: Carcasses of mammals with well-preserved soft tissues from the permafrost of Siberia and northern North America are among the most important sources of our knowledge on Quaternary environments. However, the potential of this information source is far from being exhausted. The objective of this study is to reveal and describe the remains of freshwater invertebrates in the hair and gut contents of large Pleistocene mammals stored for a long time in museum collections. We have studied the gut contents of two mammoths, as well as the hair of two other mammoths, one woolly rhinoceros, four bison, and two horses. Remains of invertebrates were found in the gut contents of both mammoths, as well as in the hair of two mammoths and the woolly rhinoceros, while no remains were detected in the bison and horse hair. Among the remains of microscopic invertebrates, the most common are branchiopod crustaceans, namely the ephippia of Daphnia sp., Simocephalus sp., the head shields and valves of Chydoridae (Cladocera), and the mandibles of tadpole shrimps (Notostraca). Based on our current level of knowledge, we are able to identify only a limited number of Pleistocene branchiopods. Studies on Recent taxa with the aim to develop identification keys to the aforementioned groups are needed, as they could significantly expand the potential of palaeoecological analysis