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

Quantum effects in multilayer Si-Ge nanoheterostructures

The lateral photoconductivity spectra and photofield electron emission were used to investigate multilayer Ge/Si heterostructures with Ge quantum dots. Earlier we have revealed a close connection between elastic strain in Ge quantum dots originating due to the lattice mismatch during the epitaxial growth and additional energy level forming in the strained Si-Ge heterojunction region. Thus, it appeared to be possible observing intraband transitions in Ge quantum dots that are absent in two-dimensional Si-Ge heterostructures using such simple and informative methods. While an influence of the number of Ge quantum dot layers on lateral photoconductivity spectra is not essential, the photofield electron emission characteristics showed considerable shift to middle infrared area, as the number of Ge quantum dot layers increased. It was revealed that size and composition parameters of Ge quantum dots correspond to energy levels in the valence band of the latter with the energy distance between them about 0.32 and 0.34 eV with a high accuracy. The results of our investigation make it possible to expect their possible application in new nano- and optoelectronic devices.Методами фотопольової емісії та повздовжньої фотопровідності було досліджено багатошарові наногетероструктури з квантовими точками германію. Попередні дослідження показали тісний зв'язок пружних напружень, що виникають при епітаксійному рості матеріалів з різними постійними граток, з виникненням додаткових рівнів в зоні такого гетеропереходу. Таким чином, відносно простими але інформативними методами спостерігалися міжзонні переходи, які відсутні в двовимірних гетероструктурах Si-Ge. Якщо вплив кількості шарів на фотопольову емісію несуттєвий, то при дослідженні фотопровідності виявлено прямий зв'язок зсуву чутливості повздовжньої фотопровідності в середній інфрачервоний діапазон від кількості шарів з квантовими точками германію. Показано, що розмірні характеристики та мольний склад квантових точок відповідають енергетичним рівням з енергетичною відстанню між ними приблизно 0,32 та 0,34 еВ з дуже високою точністю. Результати досліджень дозволяють сподіватися на їх використання в перспективних приладах нано- та оптоелектроніки

7 GHz pulsed magnicon amplifier

The work on creation of high-power microwave amplifiers with circular deflection of an electron beam has been carried out at INP since 1967. In the latest set of experiments on 7 GHz magnicon almost all design parameters have been achieved: the output power of 55 MW, efficiency of 56 %, and gain of 72 dB. Experimental data are in an excellent agreement with simulation results obtained by the special magnicon computer codes. Achieved results allow us to consider a magnicon as an alternative power source for linear colliders applications

Study of the process e+e−→3(π+π−) in the c.m. energy range 1.5–2.0 GeV with the CMD-3 detector

AbstractThe cross section of the process e+e−→3(π+π−) has been measured using a data sample of 22 pb−1 collected with the CMD-3 detector at the VEPP-2000 e+e− collider. 7956 signal events are selected in the center-of-mass energy range 1.5–2.0 GeV. The measured cross section exhibits a sharp drop near the pp¯ threshold. A first study of dynamics of six-pion production has been performed

METHOD FOR ASSESSING THE ACTIVITIES OF THE ORGANIZATION (BY THE EXAMPLE OF THE AUTHORITIES OF THE STATE FIRE SUPERVISION EMERCOM OF RUSSIA)

Background. With the introduction of the updated regulatory legal documents regulating the procedures for the implementation of supervisory activities and preventive work, inquiries on fire cases, licensing and the provision of services in the field of fire safety, it became necessary to adjust the methods for assessing the activities of state fire supervision authorities. In this regard, one of the goals of improving the forms and methods of work of supervisory authorities in the field of fire safety is to develop a system of indicators, criteria and models for evaluating their activities from the standpoint of applying the mechanisms to the functioning of organizational structures. Materials and methods. To develop a model for evaluating the activities of the state fire supervision authorities, the statistical data generated in the information systems of the Ministry of Emergency Situations of Russia for the implementation of supervisory activities and preventive work, inquiry into fire cases, licensing and provision of services in the field of fire safety were studied. Based on the application of the Harrington function, calculated dependencies were developed for quantitative assessments of activities, both in its individual areas and in their totality. Results. Using the mechanisms of functioning of organizational structures, in relation to the activities of state fire supervision bodies, method for assessing the activities of an organization has been developed, including a system of indicators, criteria and mathematical dependencies. The method has been implemented in the EMERCOM of Russia. Conclusions. The proposed method makes it possible to carry out quantitative assessments of the activities of organizations and determine their comparative ratings

Methods for architecture synthesis of broadband wireless networks with linear topology

A novel iterative algorithm for designing the architecture of broadband wireless networks along the long highways is considered. The mathematical problems were formulated and solved for every step of the iterative method. An example is given of designing a broadband wireless network along the highways in one of the regions of Russia