Professor Lian Nedelchev, PhD

Department "Optical Metrology and Holography", Laboratory "Holography"

Institute of Optical Materials and Technologies “Acad. J. Malinowski”, Bulgarian Academy of Sciences

E-mail: lian@iomt.bas.bg

2004 PhD in Physics, on Electric, magnetic and optical properties of condensed matter; Institute of Optical Materials and Technologies “Acad. J. Malinowski”, BAS

1997 Master of Physics (Laser Physics), Sofia University “St. Kl. Ohridski”, Sofia, Bulgaria

2022 – present Professor

Institute of Optical Materials and Technologies – Bulgarian Academy of Sciences;

2011 – 2022 Assoc. Professor

Institute of Optical Materials and Technologies – Bulgarian Academy of Sciences;

2009 – 2021 Assoc. Professor

University of Telecommunications and Post;

Dean of Faculty of Telecommunications and Management (2015 - 2019),

1997 – 2010 Physicist, PhD student, Research associate

Central Laboratory of Optical Storage and Processing of Information – Bulgarian Academy of Sciences

2001 – 2002 Research Associate

Optilink A/S and Risoe National Laboratory, Roskilde (Denmark);

Polarization holography, diffractive optical elements, laser physics, photoinduced anisotropy, polarimetry, azopolymers, optical data storage, hybrid and nanocomposite materials

Total number of publications: 113

Publications with impact factor or impact rang: 94

Total number of citations (self-citations excluded): 491

Н index (according to Scopus or Web of Science): 14

Supervisor of the following PhD students: Georgi Mateev, Blaga Blagoeva (IOMT-BAS)

Consultant of the PhD student Georgi Dobrinkov (IMI-BAS)

External examiner of PhD student for the Dublin Institute of Technology (2019)

Course, taught for the PhD Center of BAS: "Polarization holography and applications: holographic data storage in anisotropic materials"

Projects with international funding:

1. Visualization quality in digital incoherent and polarization holography, speckle imaging and OCT(2024); Funded by: Electronics and Telecommunications Research Institute (ETRI), Republic of Korea
2. Quality assessment of GP-SIDH, polarization holography, and speckle analysis (2023); Funded by: Electronics and Telecommunications Research Institute (ETRI), Republic of Korea
3. Coherent acquisition and processing in incoherent digital holography, polarization holograhpy and dynamic speckle metrology (2022); Funded by: Electronics and Telecommunications Research Institute (ETRI), Republic of Korea
4. Quality enhancement in self-interference incoherent digital holography, polarization holography and dynamic speckle analysis (2021); Funded by: Electronics and Telecommunications Research Institute (ETRI), Republic of Korea
5. Research on recording of polarization holograms and quantization on dynamic holograms (2020); Funded by: Electronics and Telecommunications Research Institute (ETRI), Republic of Korea
6. Research on direct acquisition and data compression in digital hologrаphy (2019); Funded by: Electronics and Telecommunications Research Institute (ETRI), Republic of Korea
7. Advances in Optofluidics: Integration of Optical Control and Photonics with Microfluidics; COST Action MP1205; Project coordinator: Prof. Gabriella CIPPARRONE (2012 - 2016);

Projects with national funding:

1. Polarization and coherent optical methods for the study of photosensitive and photoanisotropic materials; Contract No.: КП-06-Н88/2 from 27.11.2024; Project coordinator: Assoc. Prof. Nataliya Berberova-Buhova
2. Tunable optical elements based on holographic, computer generated and chiral structures; Contract No.: Н 38/15 from 17.12.2019; Project coordinator: Prof. Lian Nedelchev
3. Novel azo materials and application of their photo-physical properties in devices for reversible optical recording; Contract No.: ДН 18/5 from 10.12.2017; Project coordinator: Assoc. Prof. Anton Georgiev
4. Reversible polarization holographic recording in anisotropic azopolymer based nanocomposites; Contract No.: ДН 08/10 from 13.12.2016; Project coordinator: Assoc. Prof. Dimana Nazarova
5. Holographic visualization, light beams shaping and speckle metrology by computer generated holograms; Contract No.: ДН 08/13 from 16.12.2016; Project coordinator: Prof. Elena Stoykova
6. Advances in Optofluidics: Integration of Optical Control and Photonics with Microfluidics; Contract No.: ДКОСТ 01/7 from 15.08.2016; Project coordinator: Assoc. Prof. Dimana Nazarova
7. New hybrid structures based on photorefractive crystal-liquid crystal and graphene; Contract No.: ДФНИ -T-02/26 from 12.12.2014; Project coordinator: Prof. Vera Marinova
8. National centre for mechatronics and clean technologies; Contract No.: BG05M20P001-1.001; Project coordinator: Prof. Nikola Malinovski
9. Development of applied research in IOMT through advanced optical materials for modern applications; Contract No.: BG16 1P0003-1.2.04, No. 1.2.04-0034-C0001; Project coordinator: Prof. Nikola Malinovski

2020 - 2025 Member of SPIE (Society of Photo-Optical Instrumentation Engineers)

2021 - 2024 Member of Optica (former Optical Society of America - OSA)

1. D. Minkov, L. Nedelchev, G. Angelov, E. Marquez, B. Blagoeva, G. Mateev, D. Nazarova, Hybrid dispersion model characterization of PAZO polymer thin films over the entire transmittance spectrum measured in the UV/VIS/NIR spectral region. Materials, vol. 15, art.no. 8617 (12 pp), 2022.
2. E. Stoykova, B. Blagoeva, N. Berberova-Buhova, M. Levchenko, D. Nazarova, L. Nedelchev, J. Park, Intensity-based dynamic speckle method using JPEG and JPEG2000 compression. Applied Optics, vol. 61, pp. B287-B296, 2022.
3. L. Nedelchev, G. Mateev, V. Strijkova, V. Salgueiriño, D. Schmool, N. Berberova-Buhova, E. Stoykova, D. Nazarova, Tunable Polarization and Surface Relief Holographic Gratings in Azopolymer Nanocomposites with Incorporated Goethite (α-FeOOH) Nanorods. Photonics, vol. 8, art. no. 306 (12 pp), 2021.
4. B. Blagoeva, L. Nedelchev, D. Nazarova, E. Stoykova, J. Park, Reversible supramolecular chiral structures induced in azopolymers by elliptically polarized light: Influence of the irradiation wavelength and intensity. Applied Optics, vol. 61, pp. B147-B155, 2021.
5. N. Berberova-Buhova, L. Nedelchev, G. Mateev, E. Stoykova, V. Strijkova, D. Nazarova, Influence of the size of Au nanoparticles on the photoinduced birefringence and diffraction efficiency of polarization holographic gratings in thin films of azopolymer nanocomposites. Optical Materials, vol. 121, art. no. 111560 (9 pp), 2021.
6. A. Stoilova, G. Mateev, D. Nazarova, L. Nedelchev, E. Stoykova, B. Blagoeva, N. Berberova, S. Georgieva, P. Todorov, Polarization holographic gratings in PAZO polymer films doped with particles of biometals. Journal of Photochemistry and Photobiology A: Chemistry, vol. 411, art. no. 113196 (6 pp), 2021.
7. E. Stoykova, D. Nazarova, L. Nedelchev, B. Blagoeva, N. Berberova, K. Hong, J. Park, Quantization of dynamic speckle patterns with spatially varying statistics. Applied Optics, vol. 60, pp. A155-A165, 2021.
8. D. Nazarova, G. Mateev, L. Nedelchev, E. Stoykova, B. Blagoeva, N. Berberova, K. Hong, J. Park, Polarization holographic gratings with enhanced parameters recorded in azopolymer based nanocomposite materials. Optik - International Journal for Light and Electron Optics, vol. 226, art. no 165882 (11 pp), 2020.
9. L. Nedelchev, E. Stoykova, G. Mateev, B. Blagoeva, A. Otsetova, D. Nazarova, K. Hong, J. Park, Photoinduced chiral structures in case of polarization holography with orthogonally linearly polarized beams. Optics Communications, vol. 461, pp. 125269: 1-5, 2020.
10. B. Blagoeva, L. Nedelchev, G. Mateev, E. Stoykova, D. Nazarova, Diffraction efficiency of polarization holographic gratings recorded in azopolymer thin films coated using different solvents. Proceedings of SPIE, vol. 11367, pp. 113671G-1-113671G-6, 2020.
11. E. Stoykova, D. Nazarova, L. Nedelchev, B. Ivanov, B. Blagoeva, K. Oh, J. Park, Dynamic speckle analysis with coarse quantization of the raw data. Applied Optics, vol. 59, pp. 2810-2819, 2020.
12. G. Mateev, G. Marinov, L. Nedelchev, D. Nazarova, E. Stoykova, T. Babeva, Improvement of the photoinduced birefringence in azopolymer PAZO doped with ZnO via electrospray deposition. Journal of Physics: Conference Series, vol. 1492, pp. 012041: 1-5, 2020.
13. L. Nedelchev, D. Ivanov, B. Blagoeva, D. Nazarova “Optical anisotropy induced at five different wavelengths in azopolymer thin films: Kinetics and spectral dependence”, Journal of Photochemistry and Photobiology A: Chemistry, vol. 376, pages 1-6, 2019.
14. R. Harizanova, V. Gaydarov, G. Zamfirova, E. Stoykova, D. Nazarova, B. Blagoeva, L. Nedelchev “Probing of the mechanical properties and monitoring of the drying process of azopolymer thin films for optical recording”, Thin Solid Films, vol. 687, pages 137441-1-137441-8, 2019.
15. A. Stoilova, A. Georgiev, L. Nedelchev, D. Nazarova, D. Dimov “Structure-property relationship and photoinduced birefringence of the azo and azo-azomethine dyes thin films in PMMA matrix”, Optical Materials, vol. 87, pages 16-23, 2019.
16. N. Berberova, P. Sharlandjiev, D. Nazarova, L. Nedelchev “Optical response of azopolymer (PAZO) layers doped with TiO2 nanoparticles”, Proceedings of SPIE, vol. 11047, pages 110470F-1-110470F-4, 2019.
17. L. Nedelchev, D. Ivanov, N. Berberova, V. Strijkova, D. Nazarova “Polarization holographic gratings with high diffraction efficiency recorded in azopolymer PAZO”, Optical and Quantum Electronics, vol. 50, pages 212-1-212-9, 2018.
18. L. Nedelchev, G. Mateev, A. Otsetova, D. Nazarova, E. Stoykova “Optimization of deposition of thin photoanisotropic films for holographic data storage”, International Journal Information Theories and Applications, vol. 25, pages 245-254, 2018.
19. A. Georgiev, A. Kostadinov, D. Ivanov, D. Dimov, S. Stoyanov, L. Nedelchev, D. Nazarova, D. Yancheva “Synthesis, Spectroscopic and TD-DFT Quantum Mechanical Study of Azo- Azomethine Dyes. A Laser Induced Trans-Cis-Trans Photoisomerization Cycle”, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol. 192, pages 263-274, 2018.
20. G. Mateev, L. Nedelchev, D. Ivanov, R. Tomova, P. Petrova, V. Strijkova, N. Berberova, D. Nazarova “Polarization holographic gratings in azopolymer PAZO recorded with different recording beams polarizations”, Journal of Physics: Conference Series, vol. 992, pages 012056-1-012056-5, 2018.
21. E. Stoykova, G. Mateev, B. Blagoeva, L. Nedelchev, D. Nazarova “Monte-Carlo simulation of the birefringence kinetics in azobenzene-containing materials”, Journal of Physics: Conference Series, vol 992, pages 012020-1-012020-6, 2018.
22. D. Nazarova, P. Sharlandjiev, N. Berberova, B. Blagoeva, E. Stoykova, L. Nedelchev “Diffraction efficiency calculations of polarization diffraction gratings with surface relief”, Journal of Physics: Conference Series, vol. 992, pages 012018-1-012018-5, 2018.
23. N. Berberova, D. Daskalova, V. Strijkova, D. Kostadinova, D. Nazarova, L. Nedelchev, E. Stoykova, V. Marinova, C. H. Chi, S. H. Lin “Polarization holographic recording in thin films of pure azopolymer and azopolymer based hybrid materials”, Optical Materials, vol. 64, pages 212-216, 2017.
24. L. Nedelchev, D. Nazarova, B. Blagoeva, D. Ivanov, D. Daskalova, N. Berberova, G. Mateev, D. Kostadinova “Time dependent spectral birefringence excited with laser light in azopolymers and azopolymers doped with ZnO”, Proceedings of SPIE, vol. 10226, pages 1022606-1-1022606-6, 2017.
25. D. Nazarova, L. Nedelchev, D. Ivanov, B. Blagoeva, N. Berberova, E. Stoykova, G. Mateev, D. Kostadinova “Laser induced optically and thermally reversible birefringence in azopolymers”, Proceedings of SPIE, vol. 10226, pages 1022608-1-1022608-7, 2017.
26. L. Nedelchev, D. Ivanov, G. Mateev, B. Blagoeva, D. Kostadinova, N. Berberova, D. Nazarova “Multiple cycles of recording/reading/erasing birefringence in azopolymers”, Bulgarian Chemical Communications, vol. 48G, pages 33-36, 2016.
27. L. Nedelchev, D. Nazarova, N. Berberova, G. Mateev, D. Kostadinova, R. Mariño-Fernández, V. Salgueiriño, D. Schmool “Enhanced photoanisotropic response in azopolymer doped with elongated goethite nanoparticles”, Journal of Physics: Conference Series, vol. 700, pages 012031-1-012031-5, 2016.
28. D. I. Nazarova, L. L. Nedelchev, P. S. Sharlandjiev, V. D. Dragostinova “Anisotropic hybrid organic/inorganic (azopolymer/SiO2 NP) materials with enhanced photoinduced birefringence”, Applied Optics, vol. 52, no. 22, page E28 - E33, 2013.
29. L. Nedelchev, D. Nazarova, V. Dragostinova, D. Karashanova, “Increase of photoinduced birefringence in a new type of anisotropic nanocomposite: azopolymer doped with ZnO nanoparticles”, Optics Letters, vol. 37, no. 13, page 2676 – 2678, 2012.
30. N. Berberova, D. Nazarova, L. Nedelchev, B. Blagoeva, D. Kostadinova, V. Marinova, E. Stoykova, “Photoinduced variation of the Stokes parameters of light passing through thin films of azopolymer based hybrid organic/inorganic materials”, Journal of Physics: Conference Series (JPCS), vol. 700, page 012032, 2016.
31. D. P. Ilieva, L. L. Nedelchev, D. I. Nazarova, „Photoinduced anisotropy in azodyes Alizarin Yellow R and Mordant Pure Yellow in a gelatin matrix”, Bulgarian Chemical Communications, vol. 45B, page 137 – 140, 2013.
32. L. Nedelchev, D. Nazarova, G. Mateev, N. Berberova, „Birefringence induced in azopolymer (PAZO) films with different thickness”, Proc. of SPIE, vol. 9447, page 94471I-1 - 94471I-7, 2015.
33. L. L. Nedelchev, D. I. Nazarova, V. D. Dragostinova, P. K. Petkov, A. A. Stoilova, „Photoinduced anisotropy in a series of azobenzene copolymers”, Bulgarian Chemical Communications, vol. 45B, page 145 – 148, 2013.
34. L. L. Nedelchev, D. I. Nazarova, „Time stability of photoinduced birefringence in amorphous and liquid-crystalline azopolymers”, Bulgarian Chemical Communications, vol. 45B, page 141 – 144, 2013.
35. D. Ilieva, L. Nedelchev, “Photoinduced anisotropy and polarization holography on UV exposure in films of N-benzylideneaniline in PMMA matrix”, Optica Applicata, vol. 42, page 207, 2012.
36. N.C.R. Holme, S. Hvilsted, E. Lorincz, E. Matharu, L. Nedelchev, L. Nikolova, P.S. Ramanujam “Azobenzene polyesters for polarization holographic storage. Part 1. Materials and characterization”, in “Handbook of Organic Electronics and Photonics”, H. S. Nalwa (Ed.), American Scientific Publishers, Valencia CA, 2007, 184–211.
37. D. Ilieva, L. Nedelchev, Ts. Petrova, V. Dragostinova, T. Todorov, L. Nikolova, P.S. Ramanujam “Photoinduced processes and holographic storage in stilbene and stilbenecarboxaldehyde in a polymethylmethacrylate matrix”, Journal of Optics A: Pure and Applied Optics, vol. 8, page 221, 2006.
38. D. Ilieva, L. Nedelchev, Ts. Petrova, N. Tomova, V. Dragostinova, L. Nikolova “Holographic multiplexing using photoinduced anisotropy and surface relief in azopolymer films”, Journal of Optics A: Pure and Applied Optics, vol. 7, page 35, 2005.
39. L. Nedelchev, D. Ilieva, Ts. Petrova, N. Tomova, V. Dragostinova, L. Nikolova “Polarization multiplexing of holograms in azopolymer films”, Proceedings of SPIE, vol. 5830, page 95, 2005.
40. P.S. Ramanujam, L. Nedelchev, A. Matharu “Polarization holographic and surface relief gratings at 257 nm in an amorphous azobenzene polyester”, Optics Letters, vol. 28, page 1072, 2003.
41. L. Nedelchev, A. Matharu, S. Hvilsted, P.S. Ramanujam “Photoinduced anisotropy in a family of amorphous azobenzene polyesters for optical storage”, Applied Optics, vol. 42, page 5918, 2003.
42. L. Nedelchev, A. Matharu, L. Nikolova, S. Hvilsted, P.S. Ramanujam “Propagation of polarized light through azobenzene polyester films”, Molecular Crystals and Liquid Crystals, vol. 375, page 563, 2002.
43. L. Nedelchev, L. Nikolova, A. Matharu, P.S. Ramanujam “Photoinduced macroscopic chiral structures in a series of azobenzene copolyesters”, Applied Physics B, vol. 75, page 671, 2002.
44. L. Nedelchev, L. Nikolova, T. Todorov, T. Petrova, N. Tomova, V. Dragostinova, P.S. Ramanujam, S. Hvilsted “Light propagation through photoinduced chiral structures in azobenzene-containing polymers”, Journal of Optics A: Pure and Applied Optics, vol. 3, page 304, 2001.
45. L. Nedelchev, T. Todorov, L. Nikolova, Tz. Petrova, N. Tomova, V. Dragostinova “Characteristics of high-efficient polarization holographic gratings”, Proceedings of SPIE, vol. 4397, page 338, 2001.
46. L. Nikolova, L. Nedelchev, T. Todorov, Tz. Petrova, N. Tomova, V. Dragostinova, P.S. Ramanujam, S. Hvilsted “Self-induced light polarization rotation in azobenzene-containing polymers”, Applied Physics Letters, vol. 77, page 657, 2000.