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Maksim Skorobogatiy

Publications and source records attributed to Maksim Skorobogatiy.

44 records · Page 3Linked to original sources
arXiv2010

Composite THz materials using aligned metallic and semiconductor microwires, experiments and interpretation

We report fabrication method and THz characterization of composite films containing either aligned metallic (tin alloy) microwires or chalcogenide As2Se3 microwires. The microwire arrays are made by stack-and-draw fiber fabrication technique using multi-step co-drawing of low-melting-temperature metals or semiconductor glasses together with polymers. Fibers are then stacked together and pressed into composite films. Transmission through metamaterial films is studied in the whole THz range (0.1-20 THz) using a combination of FTIR and TDS. Metal containing metamaterials are found to have strong polarizing properties, while semiconductor containing materials are polarization independent and could have a designable high refractive index. Using the transfer matrix theory, we show how to retrieve the complex polarization dependent refractive index of the composite films. We then detail the selfconsistent algorithm for retrieving the optical properties of the metal alloy used in the fabrication of the metamaterial layers by using an effective medium approximation. Finally, we study challenges in fabrication of metamaterials with sub-micrometer metallic wires by repeated stack-and-draw process by comparing samples made using 2, 3 and 4 consecutive drawings. When using metallic alloys we observe phase separation effects and nano-grids formation on small metallic wires.

physics.optics↗
arXiv2010

Jacquard-woven photonic bandgap fiber displays

We present an overview of photonic textile displays woven on a Jacquard loom, using newly discovered polymer photonic bandgap fibers that have the ability to change color and appearance when illuminated with ambient or transmitted light. The photonic fiber can be thin (smaller than 300 microns in diameter) and highly flexible, which makes it possible to weave in the weft on a computerized Jacquard loom and develop intricate double weave structures together with a secondary weft yarn. We demonstrate how photonic crystal fibers enable a variety of color and structural patterns on the textile, and how dynamic imagery can be created by balancing the ambient and emitted radiation. Finally, a possible application in security ware for low visibility conditions is described as an example.

physics.optics↗
arXiv2010

Soft capacitor fibers using conductive polymers for electronic textiles

A novel, highly flexible, conductive polymer-based fiber with high electric capacitance is reported. In its crossection the fiber features a periodic sequence of hundreds of conductive and isolating plastic layers positioned around metallic electrodes. The fiber is fabricated using fiber drawing method, where a multi-material macroscopic preform is drawn into a sub-millimeter capacitor fiber in a single fabrication step. Several kilometres of fibers can be obtained from a single preform with fiber diameters ranging between 500um -1000um. A typical measured capacitance of our fibers is 60-100 nF/m and it is independent of the fiber diameter. For comparison, a coaxial cable of the comparable dimensions would have only ~0.06nF/m capacitance. Analysis of the fiber frequency response shows that in its simplest interrogation mode the capacitor fiber has a transverse resistance of 5 kOhm/L, which is inversely proportional to the fiber length L and is independent of the fiber diameter. Softness of the fiber materials, absence of liquid electrolyte in the fiber structure, ease of scalability to large production volumes, and high capacitance of our fibers make them interesting for various smart textile applications ranging from distributed sensing to energy storage.

physics.chem-ph↗
arXiv2010

Photonic bandgap fiber bundle spectrometer

We experimentally demonstrate an all-fiber spectrometer consisting of a photonic bandgap fiber bundle and a black and white CCD camera. Photonic crystal fibers used in this work are the large solid core all-plastic Bragg fibers designed for operation in the visible spectral range and featuring bandgaps of 60nm - 180nm-wide. 100 Bragg fibers were chosen to have complimentary and partially overlapping bandgaps covering a 400nm-840nm spectral range. The fiber bundle used in our work is equivalent in its function to a set of 100 optical filters densely packed in the area of ~1cm2. Black and white CCD camera is then used to capture spectrally "binned" image of the incoming light at the output facet of a fiber bundle. To reconstruct the test spectrum from a single CCD image we developed an algorithm based on pseudo-inversion of the spectrometer transmission matrix. We then study resolution limit of this spectroscopic system by testing its performance using spectrally narrow test peaks (FWHM 5nm-25nm) centered at various positions within the 450nm-700nm spectral interval. We find that the peak center wavelength can always be reconstructed within several percent of its true value regardless of the peak width or position. We believe that photonic bandgap fiber bundle-based spectrometers have a potential to become an important technology in multispectral imaging because of their simplicity (lack of moving parts), instantaneous response, and high degree of integration.

physics.optics↗
arXiv1998

Snaking of a fluid in two dimensions

The nature of physical processes can depend substantially on the dimensionality of a system. One such example are buckling instabilities, which arise from the competition between axial compression and bending in elastic filaments. Thus, coiling of a jet of viscous fluid falling on a substrate (honey poured on a toast) \cite{maha1,griffiths} behaves quite differently from the coiling of viscous sheets (volcanous lava sliding on a crust) \cite{johnson,ramberg}. Here we consider a novel effect of coiling of a fluid jet confined to a two dimensional film.

cond-mat.soft↗
arXiv1998

Non-Arrhenius modes in the relaxation of model proteins

We have investigated the relaxational dynamics for a protein model at various temperatures. Theoretical analysis of this model in conjunction with numerical simulations suggests several relaxation regimes, including a single exponential, a power law and a logarithmic time dependence. Even though a stretched exponential form gives a good fit to the simulation results in the crossover regime between a single exponential and a power law decay, we have not been able to directly deduce this form from the theoretical analysis.

cond-mat.stat-mech↗
arXiv1998

A Deterministic Approach to the Protein Design Problem

We have considered the problem of protein design based on a model where the contact energy between amino acid residues is fitted phenomenologically using the Miyazawa--Jernigan matrix. Due to the simple form of the contact energy function, an analytical prescription is found which allows us to design energetically stable sequences for fixed amino acid residues compositions and target structures. The theoretically obtained sequences are compared with real proteins and good correspondence is obtained. Finally we discuss the effect of discrepancies in the procedure used to fit the contact energy on our theoretical predictions.

cond-mat.soft↗