Prof. Dr. Tsvetanka Babeva
Institute of Optical Materials and Technologies ‘‘Acad. J. Malinowski’’, Bulgarian Academy of Sciences
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Academic Career Length
19Years (2008-Present)
(Calculated once Scilit publication data is synced: current year − year of first publication + 1)
Representative Publications
View All Publications1 June 2014 in Optics & Laser Technology
Journal Article
KLK. Lazarova
K. Lazarova
MVM. Vasileva
M. Vasileva
GMGeorgi Marinov
Georgi MarinovTsvetanka Babeva7 January 2010 in Journal of the Optical Society of America B
Journal Article
Tsvetanka Babeva
Izabela NaydenovaDMDana Mackey
Dana Mackey
SMSuzanne Martin
Suzanne MartinVTVincent Toal
Vincent ToalA theoretical model for formation of a short-exposure holographic grating is presented. The model accounts for both monomer and polymer diffusion and distinguishes between short polymer chains capable of diffusing and long polymer chains that are immobile. It is shown that the experimentally observed decrease of diffraction efficiency at higher spatial frequency can be predicted by assuming diffusion of short-chain polymers away from the bright fringes. The time evolution of the refractive-index modulation after a short exposure is calculated and compared with experimental results. The effects of diffusion coefficients, polymerization rates, intensity, and spatial frequency of recording on the properties of weak diffraction gratings are investigated by numerical simulations.
Journal Article
KLKaterina Lazarova
Katerina LazarovaHAHussein Awala
Hussein AwalaSTSebastien Thomas
Sebastien ThomasMVMarina Vasileva
Marina Vasileva
Svetlana MintovaTsvetanka BabevaThe preparation of responsive multilayered structures with quarter-wave design based on layer-by-layer deposition of sol-gel derived Nb2O5 films and spin-coated MEL type zeolite is demonstrated. The refractive indices (n) and thicknesses (d) of the layers are determined using non-linear curve fitting of the measured reflectance spectra. Besides, the surface and cross-sectional features of the multilayered structures are characterized by scanning electron microscopy (SEM). The quasi-omnidirectional photonic band for the multilayered structures is predicted theoretically, and confirmed experimentally by reflectance measurements at oblique incidence with polarized light. The sensing properties of the multilayered structures toward acetone are studied by measuring transmittance spectra prior and after vapor exposure. Furthermore, the potential of the one-dimensional photonic crystals based on the multilayered structure consisting of Nb2O5 and MEL type zeolite as a chemical sensor with optical read-out is discussed.
Journal Article
SBSilviya Boycheva
Silviya Boycheva
Denitza ZgurevaKLKaterina Lazarova
Katerina LazarovaTsvetanka Babeva
Cyril PopovMPMargarita Popova
Margarita Popova +1
Fly ash (FA) from lignite coal combusted in different Thermal Power Plants (TPPs) was used for the synthesis of zeolites (FAZs) of the Na-X type by alkaline activation via three laboratory procedures. FAZs were characterized with respect to their morphology, phase composition and surface properties, which predetermine their suitability for applications as catalysts and adsorbents. FAZs were subsequently modified with metal oxides (CuO) to improve their catalytic properties. The catalytic activity of non-modified and CuO-modified FAZs in the total oxidation of volatile organic compounds was investigated. FAZs were studied for their potential to retain CO2, as their favorable surface characteristics and the presence of iron oxides make them suitable for carbon capture technologies. Thin films of FAZs were deposited by in situ crystallization, and investigated for their morphology and optical sensitivity when exposed to pollutants in the gas phase, e.g., acetone. This study contributes to the development of novel technological solutions for the smart and valuable utilization of FA in the context of the circular economy and green energy production.
Journal Article
KLKaterina Lazarova
Katerina LazarovaSBSilvia Mladenova Bozhilova
Silvia Mladenova BozhilovaSISijka Ivanova
Sijka IvanovaDCDarinka Christova
Darinka ChristovaTsvetanka BabevaThin spin-coated polymer films of amphiphilic copolymer obtained by partial acetalization of poly (vinyl alcohol) are used as humidity-sensitive media. They are deposited on polymer substrate (PET) in order to obtain a flexible humidity sensor. Pre-metallization of substrate is implemented for increasing the optical contrast of the sensor, thus improving the sensitivity. The morphology of the sensors is studied by surface profiling, while the transparency of the sensor is controlled by transmittance measurements. The sensing behavior is evaluated through monitoring of transmittance values at different levels of relative humidity gradually changing in the range 5–95% and the influence of up to 1000 bending deformations is estimated by determining the hysteresis and sensitivity of the flexible sensor after each set of deformations. The successful development of a flexible sensor for optical monitoring of humidity in a wide humidity range is demonstrated and discussed.
19 April 2018 in Optical and Quantum Electronics
Journal Article
YSY. C. Su
Y. C. Su
CCC. C. Chiou
C. C. Chiou
VMV. Marinova
V. Marinova
SLS. H. Lin
S. H. Lin
NBN. Bozhinov
N. BozhinovDDDimitre Dimitrov
Dimitre Dimitrov +3
About Me
Tsvetanka Babeva is currently Full Professor and Director of the Institute of Optical Materials and Technology at the Bulgarian Academy of Sciences, Sofia, Bulgaria. She received her M.S. in physics, major applied optics at Sofia University in 1994 and PhD in Physics of condensed matter at Central Laboratory of Photoprocesses, Bulgarian Academy of Science in 2003. In 2007 she was awarded Arnold F. Graves fellowship and spent 2 years as a postdoctoral researcher in Centre of Industrial and Engineering Optics at Dublin Institute of Technology (now Technological University of Dublin), Ireland. Her professional experience includes 30 years as a researcher, supervision of PhD and master students, post-doctoral researcher etc., participation as a team member of more than 20 projects and team leader of 9 scientific and infrastructural projects. She has co-authored more than 100 papers (https://orcid.org/0000-0003-0961-7499), h-index 17 and has more than 130 participations in national and international conferences. Her present research is devoted to optical characterization of thin films, wet method of films deposition, developing of porous materials and photonic structures for optical sensing applications.