A5083468710- Liquid Crystal Research Advancements
- Photochromic and Fluorescence Chemistry
- Thermoregulation and physiological responses
- Photonic Crystals and Applications
- Optical Polarization and Ellipsometry
- Optical Coatings and Gratings
- Photonic and Optical Devices
- Photorefractive and Nonlinear Optics
- Surface Roughness and Optical Measurements
- Visual perception and processing mechanisms
- Photochemistry and Electron Transfer Studies
- Advanced Optical Imaging Technologies
- Optical measurement and interference techniques
- Nonlinear Optical Materials Research
- Surfactants and Colloidal Systems
- Optical Imaging and Spectroscopy Techniques
- Calibration and Measurement Techniques
- Computer Graphics and Visualization Techniques
- Industrial Vision Systems and Defect Detection
- Advanced Fluorescence Microscopy Techniques
- Spectroscopy Techniques in Biomedical and Chemical Research
- Semiconductor materials and devices
- Electronic and Structural Properties of Oxides
- Spectroscopy and Chemometric Analyses
- Luminescence and Fluorescent Materials
Bulgarian Academy of Sciences
2015-2024
University of Chemical Technology and Metallurgy
2023-2024
Sofia University "St. Kliment Ohridski"
2023-2024
Institute of Optical Materials and Technologies Jordan Malinowski
2014-2023
Optica
2012
Drexel University
2010
State Research Institute for Chemistry and Technology of Organoelement Compounds
2010
Intensity-based pointwise non-normalized algorithms for 2D evaluation of activity in optical metrology with dynamic speckle analysis are studied and compared. They applied to a temporal sequence correlated patterns formed at laser illumination the object surface. Performance each algorithm is assessed through histogram estimates it produces. A new proposed that provides same quality map less computational effort. The both synthetic experimental data.
Abstract Polarization diffraction gratings with various profiles were created using a reflective phase spatial light modulator (SLM). A digital polarization holographic setup, incorporating the SLM and two quarter-wave plates, was employed to record modulation of onto thin films azopolymer PAZO(poly[l-[4-(3-carboxy-4-hydroxyphenylazo)benzene sulfonamido]-1,2-ethanediyl, sodium salt]). One-dimensional two-dimensional different parameters recorded efficiency (DE) kinetics in ±1 orders obtained...
Abstract As known, during polarization holographic recording in azopolymers alongside with the volume anisotropic grating a surface relief (SRG) is also formed. In this study, we investigate of beams as they pass through grating. This analysis performed real-time process using novel optical setup that incorporates two polarimeters and power meters. enables us to gather detailed data on how SRG affects properties resulting holograms. Additionally, propose straightforward yet effective...
We report a significant increase of about 50% the photoinduced birefringence in nanocomposite films azopolymers doped with ZnO nanoparticles compared samples made from nondoped azopolymers. This is most pronounced at small concentrations 0.5% and for amorphous polymers used our study. observe also an improvement response time more than 25% some polymers, which allows faster effective polarization optical recording.
Hybrid materials based on combination of polymers and inorganic nanoparticles (NP) attracted considerable attention in the last decade due to their advantageous electrical, optical, or mechanical properties. Recently, we reported a significant improvement photoresponse by doping azopolymers with ZnO NP. To study influence composition dopant, our present work have synthesized anisotropic organic/inorganic nanocomposite incorporating 5–15 nm sized SiO2 NP side-chain azopolymer. As result...
We employ two approaches to tune the properties of concurrently inscribed volume polarization and surface relief gratings in nanocomposite thin films containing azopolymer PAZO (poly[1-4-(3-carboxy-4-hydrophenylazo)benzensulfonamido]-1,2-ethanediyl, sodium salt]) goethite (α-FeOOH) nanorods. The first one is applied on stage sample preparation by varying concentration nanorods from 0% 15%. Then, different angles between recording beams are set holographic scheme, which allow us obtain with...
Polarization-selective diffractive in-line and off-axis lenses are recorded in azopolymer thin films using polarization holography. A simple, yet efficient, to the best of our knowledge, new method is used suppress surface relief grating formation improve properties lenses. The converging for right circularly polarized (RCP) light diverging left (LCP) light. Bifocal by multiplexing. By rotating sample at 90° between exposures, two focal points these located orthogonal directions Ox Oy, so we...
During polarization holographic recording in azopolymer thin films, usually together with the volume anisotropic grating, a surface relief grating (SRG) is also formed. By using two consecutive exposures, it possible to obtain two-dimensional (2D) grating. To best of our knowledge, properties such gratings have not been studied yet. determine influence on selectivity 2D gratings, we propose methods suppress SRG formation: by varying conditions or sample structure. In these experiments used...
In this work, we study the polarization properties of diffraction gratings recorded in thin films azopolymer PAZO (poly[1-[4-(3-carboxy-4-hydroxyphenylazo)benzene sulfonamido]-1,2-ethanediyl, sodium salt]) using digital holography. Using two quarter-wave plates, phase retardation each pixel SLM is converted into azimuth rotation linearly polarized light. When recording from side sample, significant surface relief amplitude observed with atomic force microscopy. contrast, substrate sample...
Pointwise intensity-based algorithms are the most popular in dynamic laser speckle measurement of physical or biological activity. The output this is a two-dimensional map which qualitatively separates regions higher lower In paper, we have proposed filtering activity maps to enhance visualization and enable quantitative determination time scales. As first step, proved that severe spatial fluctuations within resemble signal-dependent noise. second illustrated implementation idea by applying...
We describe the optimization of holographic patterning sub-micrometre surface relief structures in an acrylamide-based photopolymer. A substantial improvement photoinduced resolution was achieved by altering photopolymer chemical composition and introducing a single step post-recording thermal treatment layers. It observed that, layers, maximum achievable spatial frequency increases from 200 to 550 lines/mm. The amplitude alteration is limited due fact that both decrease plasticizer increase...
The implementation of tissue polarimetry in medicine arises mainly for the need non-invasive and highly sensitive discrimination between healthy tumor tissues. This fast, relatively cheap method may be useful better histological diagnostics by physicians. Although, most challenging goal is to apply polarimetric optical system <i>in vivo</i> measurements, initially one have optimize using <i>ex samples, phantoms etc. paper focused on parameters from lower gastrointestinal tract polarized...
Hybrid materials synthesized by combining polymers and inorganic nanoparticles (NPs) have received considerable attention recently due to their advantageous electrical, optical, or mechanical properties. Here we present a polarimetric study of thin films prepared from photoanisotropic hybrid materials: azopolymer (poly [1-[4-(3-carboxy-4-hydroxyphenylazo)benzenesulfonamido]-1,2-ethanediyl, sodium salt]) doped with different concentrations ZnO NPs sizes below 50 nm. To obtain full information...