Petr Vařák, Ph.D.

Research interests:

Photonics, glasses for photonics, fiber lasers, study of rare earth ions.

Professional activities:

2018 - present: Institute of photonics & electronics, The Czech academy of sciences, Fiber lasers and non-linear optics team.

2016 - present: Department of inorganic chemistry, Faculty of chemical technology, UCT Prague, Laboratory of materials for photonics.

Education:

2023: Ph.D. - UCT Prague, Faculty of chemical technology, Department of inorganic chemistry. Study program: Inorganic chemistry.

2018: Ing. - UCT Prague, Faculty of chemical technology, Department of inorganic chemistry. Study program: Inorganic chemistry.

3/2017: Graduate of ATHENS program, Technische Universitat Munchen, Course TUM19 - Non-contact techniques for material testing.

2016: Bc. - UCT Prague, Faculty of chemical technology, Department of inorganic chemistry. Study program: Chemistry & technology of materials.

Current research projects:

Member of projects:

• Novel nanostructured optical fibers for fiber lasers operating at dual wavelengths

Publications:

Journal papers:

1. P. Vařák, M. Leich,  M. Kamrádek, J. Aubrecht, O. Podrazký, I. Bartoň, B. Švejkarová, A. Michalcová, K. Wondraczek, M. Jäger, I. Kašík, P. Peterka, P. Honzátko, “Nanoparticle doping and molten-core methods towards highly thulium-doped silica fibers for 0.79 μm-pumped 2 μm fiber lasers – A fluorescence lifetime study”, Journal of Luminescence, Volume 275, November 2024, 120835, Link
2. Jan Pokorný, Jan Aubrecht, Michal Kamrádek, Bára Švejkarová, Petr Vařák, Martin Grábner, and Pavel Peterka, "Depressed-cladding thulium-doped fiber for applications below 1800 nm," Opt. Express 32, 17966-17976 (2024). Link
3. P. Vařák, M. Kamrádek, J. Aubrecht, O. Podrazký, J. Mrázek, I. Bartoň, A. Michalcová, M. Franczyk, R. Buczyňski, I. Kašík, P. Petereka, P. Honzátko. Heat treatment and fiber drawing effect on the matrix structure and fluorescence lifetime of Er- and Tm-doped silica optical fibers. Vol. 14, No. 4 / 1 Apr 2024 / Optical Materials Express (2024). Link
4. P. Vařák, J. Baborák, E. Véron, A. Michalcová, J. Volf, M. Allix, P. Nekvindová. Crystallization and luminescence properties of Er/Yb-doped glass-ceramics based on A2O-ZnO-SiO2 system (A = Li, Na, K, Cs). Journal of Non-Crystalline Solids 626 (2024) 122783. Link 
5. O. Podrazký, J. Mrázek, P. Vařák, J. Proboštová, I. Bartoň, et al. Nanocrystalline ceramic coatings for the capillary fiber lasers. Proceedings Volume 12573, Specialty Optical Fibres; 125730X (2023). Link 
6. Jan Mrázek, Soňa Kamrádková, Jiří Buršík, Roman Skála, Ivo Bartoň, Petr Vařák, Yauhen Baravets & Ondřej Podrazký. Nanocrystalline (HoxY1−x)2Ti2O7 luminophores for short- and mid-infrared lasers. Journal of Sol-Gel Science and Technology. ISSN: 0928-0707, eISSN: 1573-4846 (2023). Link
7. D.C. Kirsch, A. Bednyakova, P. Varak, P. Honzatko, B. Cadier, T. Robin, A. Fotiadi, P. Peterka, M. Chernysheva. Gain-controlled broadband tuneability in self-mode-locked Thulium-doped fibre laser. Commun Phys. 5 (2022) 1–10. Link
8. P. Vařák, M. Kamrádek, J. Mrázek, O. Podrazký, J. Aubrecht, P. Peterka, P. Nekvindová, I. Kašík. Luminescence and laser properties of RE-doped silica optical fibers: The role of composition, fabrication processing, and inter-ionic energy transfers. Optical Materials: X, Vol. 15, 100177 (2022). Link
9. P. Vařák, I. Kašík, P. Peterka, J. Aubrecht, J. Mrázek, M. Kamrádek, O. Podrazký, I. Bartoň, M. Franczyk, R. Buczynski, P. Honzátko. Heat treatment and fiber drawing effect on the luminescence properties of RE-doped optical fibers (RE = Yb, Tm, Ho). Optics Express Vol. 30, Issue 6, pp. 10050-10062 (2022). Link
10. P. Vařák, P. Nekvindová, J. Baborák, J. Oswald Near-infrared photoluminescence properties of Er/Yb- and Ho/Yb-doped multicomponent silicate glass – The role of GeO2, Al2O3 and ZnO. Journal of Non-Crystalline Solids, Vol. 582 (2022). Link
11. P. Vařák, J. Mrázek, A. A. Jasim, S. Bysakh, A. Dhar, M. Kamrádek, O. Podrazký, I. Kašík, I. Bartoň, P. Nekvindová „Thermal stability and photoluminescence properties of RE-doped (RE = Ho, Er, Tm) alumina nanoparticles in bulk and fiber-optic silica glass,“ Optical Materials, Vol. 118, 111239, (2021). Link
12. M. Kamrádek, J. Aubrecht, P. Vařák, J. Cajzl, V. Kubeček, P. Honzátko, I. Kašík, P. Peterka “Energy transfer coefficients in thulium-doped silica fibers,” Optical Materials Express, Vol. 11, 1805, (2021). Link
13. P. Vařák, P. Nekvindová, S. Vytykáčová, A. Michalcová, P. Malinský, J. Oswald "Near-infrared photoluminescence enhancement and radiative energy", Journal of Non-Crystalline Solids, 557, 120580 (2021). Link
14. P. Vařák, J. Mrázek, W. Blanc, J. Aubrecht, M. Kamrádek, O. Podrazký “Preparation and properties of Tm-doped SiO2-ZrO2 phase separated optical fibers for use in fiber lasers”, Optical Materials Express, Vol. 10, Issue 6 (2020). Link.
15. P. Vařák, S. Vytykáčová, P. Nekvindová, A. Michalcová, P. Malinský "The influence of copper and silver in various oxidation states on the photoluminescence of Ho3+/Yb3+ doped zinc-silicate glasses" Optical Materials (2019), 91, 253-260
16. M. Kamrádek, I. Kašík, J. Aubrecht, J. Mrázek, O. Podrazký, J. Cajzl, P. Vařák, V. Kubeček, P. Peterka, P. Honzátko „Nanoparticle and solution doping for efficient holmium fiber lasers“, IEEE Photonics Journal (2019). Link. 
17. Švecová, B.; Vařák, P.; Vytykáčová, S.; Nekvindová, P.; Macková, A.; Malinský, P.; Bottger, R.; A study of the behaviour of copper in different types of silicate glasses implanted with Cu+ and O+ ions. Nucl. Instrum. Methods Phys. Res., Sect. B 2017, 406, 193–198.
18. Vařák, P.; Švecová, B.; Horkavcová, D.; Vytykáčová, S. The preparation and characterization of copper-containing thin films prepared by the sol-gel method on various glasses. Ceramics-Silikáty 2017, 61, 99–105.

Conference papers:

1. P. Peterka, I. Bartoň, P. Vařák, M. Franzcyk, J. Aubrecht, R. Kasztelanic, M. Kamrádek, D. Pysz, O. Podrazký, I. Kašík, and R. Buczynski, "Dual-wavelength fiber lasers based on active fibers with structured cores [Invited]," in Proc SPIE Photonics West, Fiber Lasers XXI: Technology and Systems, San Francisco, USA, 26 January - 1 February 2024, p. 1286512. https://doi.org/10.1117/12.3000800 
2. P. Vařák, J. Mrázek, W. Blanc, J. Aubrecht, M. Kamrádek, O. Podrazký, P. Honzátko, "Nanocrystalline ZrO2-doped active optical fibers for fiber lasers operating at 2 μm," Proc. SPIE 11773, Micro-structured and Specialty Optical Fibres VII, 1177317 (18 April 2021); doi: 10.1117/12.2589127
3. Mrázek, J.,  Vařák, P.,  Aubrecht, J.,  Vytykáčová, S., Baravets, Y., Kašík, I.  Nanocrystalline Ceramic Luminophores for Short- and Mid-Infrared. In: 2020 22nd International Conference on Transparent Optical Networks (ICTON). 2020, p. 1-4. 
4. Vařák, P.; Nekvindová, P.; Cajzl, J.; Míka, M.; Macková, A.; Malinský, P.; Michalcová A.; Change of the luminescence properties of Tm-Yb silciate glasses by doping of silver ions using ion implantation, 18th European Confernece on Applications of Surface and Interface Analysis, Dresden, 15. 9 -20. 9. 2019, Germany.
5. Vařák, P.; Nekvindová, P.; Cajzl, J.; Oswald, J.; The effect of Zn, Al and Ge on phonon energy and Er3+ photoluminescence in silicate glasses, 8th International Workshop on Photoluminescence in Rare Earths, Photonic Materials and Devices, Nice, 4. 9. - 6. 9. 2019, France
6. Vařák, P.; Vytykáčová, S.; Nekvindová, P.; Macková, A.; The effect of silver and copper in surface layer on photoluminescence of silicate glass containing holmium and ytterbium, European Materials Research Society 2018 Fall Meeting, Warsaw, 17.9. - 20. 9. 2018, Poland
7. Vařák, P.; Vytykáčová, S.;  Nekvindová, P.; Švecová, B.; Michalcová, A.; Formation of copper metal oxide nanoparticles in silicate glasses; Slovak and Czech glass conference & seminar on defects in glasses, Trenčianské Teplice 2017, 28.6. – 30.6. 2017, Slovakia (poster).
8. Vytykáčová, S.; Vařák, P.; Akhetova, B.; Švecová, B.; Nekvindová, P.; A comparison of silver and copper containing layers in silicate glasses; Slovak and Czech glass conference & seminar on defects in glasses, Trenčianské Teplice 2017, 28.6. – 30.6. 2017, Slovakia (poster).
9. Vařák, P.; Vytykáčová, S.; Švecová, B.; Oswald, J.; Nekvindová, P.; The luminescence properties of zinc-silicate glasses; 17th European conference on applications of surface and interface analysis, Montpellier, 24.9. – 29.9. 2017, France (poster).