P. V. Kalinin

Observation of the high-Q modes inside the resonance zone of two-dimensional Bragg structures

Electrodynamical properties of two-dimensional Bragg resonators of planar geometry are studied in the frame of the geometrical-optical approach and in three-dimensional simulations. Results of the theoretical analysis are corroborated by data obtained in “cold” microwave measurements. Formation of the high-Q eigenmodes in the vicinity of the Bragg resonance frequency has been demonstrated.

1-D and 2-D metal mesh based quasi-optical selective components for high-power applications at Novosibirsk terahertz FEL

In this report we discuss main types of metal mesh based selective components of THz-quasi-optics required for applications in experiments at Novosibirsk terahertz free electron laser. The first experimental results on development of thin-film metal mesh polarizers and frequency filters by photolithographic and electroforming techniques are presented.

Experimental observation of high-Q modes at the center of a resonance band of two-dimensional Bragg structures

The electrodynamic characteristics of two-dimensional Bragg resonance structures of planar geometry have been studied. The measured frequency dependences of the coefficients of transmission and transverse scattering agree well with theoretical analysis within the framework of the geometric optics approximation and with the results of full-scale three-dimensional numerical simulations. Experimental data confirm the existence of high-Q modes in the vicinity of the frequency of the exact Bragg resonance.

Advanced Sintering Techniques in Design of Planar IT SOFC and Supported Oxygen Separation Membranes

Thin film solid oxide fuel cells (SOFC) operating in the intermediate temperature (IT) range are now considered as promising for distributed, mobile, standby or auxiliary power generation. At present one of the most important scientific aims in design of solid oxide fuel cells is to lower the operating temperatures to 600-800 С. In this temperature range, majority of problems inherent to SOFC operating at high (950-1000 C) are alleviated. Thus, cations interdiffusion and solid state reactions between electrolyte and electrodes are hampered and thermal stresses are decreased which prevent degradation of the functional layers [Yamamoto, 2004 ]. Hence, design of thin film SOFC requires also elaboration of nanostructured electrodes compatible with electrolytes from chemical and thermophysical points of view and providing a developed three-phase boundary (TPB). In this respect, broad options are provided by design of nanocomposite mixed ionic-electronic conducting (MIEC) functional layers – (Sadykov et al., 2010; Sadykov et al., 2009; Sadykov et al., 2008).

Development of thick metal mesh THz-filters by LIGA-technology for high-power applications at Novosibirsk terahertz FEL

In this paper we report about initiating technological development of thick metal mesh structures intended for frequency filtration of high-power terahertz radiation of Novosibirsk free electron laser. The technology is based on the promising LIGA-technique which employs the effect of high penetrability of X-rays into roentgenosensitive resistive layers and destined for manufacturing microstructures with extremely high aspect ratios. Due to high metallization thickness comparable with radiation wavelength LIGA-structures are expected to be much more mechanically firm and thermostable than conventional photolithographic filters, as well as to provide much higher low-frequency attenuation due to a waveguide cutoff effect. The main stages of the LIGA-technique being mastered in the Siberian Synchrotron Radiation Center are described in the paper.

Theory of a planar free-electron maser with transverse electromagnetic flux circulation in a 2D Bragg mirror

A planar free-electron maser with a resonator consisting of a 2D entrance Bragg mirror and a 1D exit Bragg mirror is theoretically studied in the framework of a nonstationary 2D model. In such a configuration, the 2D Bragg mirror provides synchronization of the radiation emitted by a wide (compared with the wavelength) ribbon-shaped electron beam. The transverse electromagnetic energy fluxes arising in this mirror are closed through an additional coupling waveguide, which provides a single-mode single-frequency masing regime insensitive to variation of the beam parameters over wide limits.

Progress in development of high-power FELs with two-dimensional Bragg resonators

Abstract Theoretical and experimental studies of novel free-electron laser (FEL) schemes with 2-D Bragg resonators of planar and coaxial geometry are discussed. The highly selective properties of 2-D Bragg resonators are described including comparison with results of “cold” microwave measurements. First results of experimental studies of a planar W-band FEL based on the accelerator ELMI (INP RAS) are presented. Progress in a coaxial Ka-band FEL experiment under construction at the University of Strathclyde is described. A new project at the Budker Institute investigating a multi-beam FEL where 2-D distributed feedback is used to synchronise several FEL units of planar geometry is also discussed.

Two-dimensional Bragg structures for powerful planar FEM (modeling and experimental testing)

Hybrid two-mirror scheme resonator are used which consists of 2D up-stream Bragg reflector and tradition 1D downstream Bragg reflector. In the frame of coupled-wave approach and direct 3D simulations (code CST MicroWave Studio) electrodynamics properties of two-mirror hybrid resonator are studied. It is demonstrated that above microwave system possesses high selectivity over both transverse and longitudinal indexes for large Fresnel parameter. Results of theoretical consideration are corroborated by experimental testing of different components of hybrid Bragg resonators.

Intercavity stimulated scattering in planar FEM as a base for two-stage generation of submillimeter radiation

Paper describes main features of a project of an experiment at ELMI-device on two-stage generation of submillimeter radiation pulses. In this experiment two parallel high current sheet beams will be used. Submillimeter waves generation is based on stimulated scattering of mm-waves accumulated in the resonator of a planar FEM-oscillator driven by one of these beams.

Selective Properties of Planar Bragg Reflectors and Their Application for Multichannel Masers

Abstract In This Paper we Discuss Selective Properties of Planar Reflectors Composed by a Pair of 1-D or 2-D Bragg Gratings with Various Types of their Surfaces Corrugation, Which can Realize One- or Two-Dimensional Distributed Feedback in a Maser. The Properties of Reflectors are Investigated by Using Theory, Computer Simulations and “cold” Measurements. Obtained Results Allow One to Create a Superpower Generator by Combining Several Identical Planar Fem-Oscillators in Common Multichannel Device. PACS Codes: 41.60. Cr, 42.25. Fx, 84.40.1k