Jan Aubrecht, Ph.D.

Research interests:

The development of characterization methods for optical fibers, fiber lasers and amplifiers.

Professional activities:

2007 - present: Institute of Photonics and Electronics of the CAS

2008 - present: Czech Technical University in Prague - Faculty of Nuclear Sciences and Physical Engineering, Department of Solid States Engineering, position: research assistent in physical fields

Education:

2019 Czech Technical University in Prague, Faculty of Electrical Engineering
University study programme at master level in Electrical engineering, power engineering a management, field of study: Economy and management of electrical engineering

2014 Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering
Doctoral study program: Applications of natural sciences, field of study: Physical engineering

2006 Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering,
Master study program: Applications of natural sciences, field of study: Physical engineering

Current Research projects:

Principal investigator of the projects:

• Fiber optic amplifier for wavelengths beyond L-band

Member of the projects:

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

Selected past research projects:

Member of the projects:

• Research of novel geometries and layouts of double-clad rare-earth-doped fibers for high power fiber lasers
• Novel optical fibers and their spectroscopy for fiber lasers operating beyond 2 um
• Self-sweeping of laser wavelength and associated instabilities of fiber lasers
• Novel silica-based Ho -doped nanomaterials for 2-μm-class fibre laser research
• Bragg fibers for delivery of high laser powers
• Tm-doped optical fibres for fibre lasers in 2 um spectral range
• Preparation and properties of silica-based optical glasses containing rare-earth- and chromium-doped nano-particles
• Regulation of morphogenesis of plant cells and organs

Publications:

Books:

1. Kalvoda L., Aubrecht J., Levinský P.,: "Development of Distributed Fiber Optic Sensor of Ammonia Gas", In Ammonia: Structure, Biosynthesis and Functions – Victoria A. Fekete and Réka L. Molnár (Eds.), Series: Chemical Engineering Methods and Technology, Nova Science Publishers, Inc., 2012, book chapter.
2. I. Kašík, O. Podrazký, J. Mrázek, J. Aubrecht, V. Matějec: "Chlorine in water," R. Mangione, D. Carlyle (Eds.): „Chlorine: Properties, applications and health effects“, Nova Science Publishers, Inc., 2011, book chapter. 
3. Sýkora, O., Aubrecht, J., Klepacek, R., Kalvoda, L: "Simulation of Distributed Detection of Ammonia Gas, " In: Computation Modelling and Advancend Simulations, Springer, Heidelberg, Computational Methods in Applied Sciences 24, 2011, book chapter.

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. M. Grábner, B. Švejkarová, J. Aubrecht, J. Pokorný, P. Honzátko, P. Peterka, "Rise of amplified spontaneous emission in high-power thulium-doped fiber lasers and amplifiers due to self-heating," in Optics & Laser Technology, vol. 180, 2025, 111428, Link
3. M. Grábner, B. Švejkarová, J. Aubrecht, J. Pokorný, P. Honzátko, P. Peterka, "Rise of amplified spontaneous emission in high-power thulium-doped fiber lasers and amplifiers due to self-heating," in Optics & Laser Technology, vol. 180, 2025, 111428, Link
4. Jan Aubrecht, Jan Pokorný, Bára Švejkarová, Michal Kamrádek, and Pavel Peterka, "Broadband thulium fiber amplifier for spectral region located beyond the L-band," Opt. Express 32, 17932-17941 (2024). Link
5. 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
6. 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
7. M. Grábner, B. Švejkarová, J. Aubrecht and P. Peterka, "Analytical Model of Thulium-Doped Fiber Laser Pumped by Two-for-One Process," in Journal of Lightwave Technology, vol. 42, no. 8, pp. 2938-2944, 15 April15, 2024, doi: 10.1109/JLT.2023.3345001
8. Pavel Peterka, Jan Aubrecht, Dariusz Pysz, Marcin Franczyk, Ondřej Schreiber, Michal Kamrádek, Ivan Kasik, and Ryszard Buczyński, "Development of pedestal-free large mode area fibers withTm3+ doped silica nanostructured core," Opt. Express 31, 43004-43016 (2023) Link
9. Bára Jiříčková, Martin Grábner, Cesar Jauregui, Jan Aubrecht, Ondřej Schreiber, and Pavel Peterka. Temperature-dependent cross section spectra for thulium-doped fiber lasers.  Opt. Lett. 48, 811-814 (2023). Link
10. 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
11. 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
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. A. Theodosiou, J. Aubrecht, I. Kašík, D. Dousek, M. Komanec, K. Kalli “Femtosecond Laser Plane-by-Plane Inscribed Cavity Mirrors for Monolithic Fiber Lasers in Thulium-Doped Fiber,” Sensors, 21(6), 1928, (2021). Link
14. F. Todorov, J. Aubrecht, P. Peterka, O. Schreiber, A. A. Jasim, J. Mrázek, O. Podrazký, M. Kamrádek, N. Kanagaraj, M. Grábner, Y. Baravets, J. Cajzl, P. Koška, A. Fišar, I. Kašík, P. Honzátko "Active Optical Fibers and Components for Fiber Lasers Emitting in the 2-μm Spectral Range", Materials, 13, 5177 (2020). Link..
15. 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.
16. J. Aubrecht, P. Peterka, P. Honzátko, O. Moravec, M. Kamrádek, I. Kašík “Broadband thulium-doped fiber ASE source”, Optics Letters, Vol. 45, No. 8 (2020). Link.
17. A. Theodosiou, J. Aubrecht, P. Peterka, I. Kasik, F. Todorov, O. Moravec, P. Honzatko, K. Kalli, "Er/Yb double-clad fibre laser with fs-laser inscribed plane-by-plane chirped FBG laser mirrors," IEEE Photonics Technology Letters, vol. 31, issue 5, pp. 409-412
18. I. Kasik, M. Kamradek, J. Aubrecht, P. Peterka, O. Podrazky, J. Cajzl, J. Mrazek, P. Honzatko, Thulium-doped optical fibers for fiber lasers operating around 2 um, Bulletin of the Polish Academy of Sciences – Technical sciences, Vol. 67, No.5, 2019, DOI: 10.24425/bpasts.2019.130883   
19. N. Kanagaraj, A. Theodosiou, J. Aubrecht, P. Peterka, M. Kamrádek, K. Kalli, I. Kašík, P. Honzátko „All fiber mode-locked thulium-doped fiber laser using a novel femtosecond-laser-inscribed 45°-plane-by-plane-tilted fiber grating“, Laser Phys. Lett. 16, 095104 (2019). Link.  
20. 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. 
21. J. Mrazek, I. Kasik, L. Prochazkova, V. Cuba, V. Girman, V. Puchy, W. Blanc, J. Aubrecht, J. Cajzl, O. Podrazky, P. Peterka, YAG ceramic nanoparticles implementation into MCVD technology of active optical fibers, Applied Sciences. Appl. Sci. 2018, 8, 833; doi:10.3390/app8050833
22. J.Cajzl, P.Peterka, M.Kowalczyk, J.Tarka, G.Sobon, J.Sotor, J.Aubrecht, P.Honzátko, I. Kašík, Thulium-doped silica fibers with enhanced fluorescence lifetime and their application in ultrafast fiber lasers, Fibers 2018, 6(3), 66; doi:10.3390/fib6030066
23. Mrazek, J.; Aubrecht, J.; Todorov, F.; Bursik, J.; Puchy, V.; Dzunda, R.; Vytykacova, S.; Kasik, I., CO2 laser-assisted preparation of transparent Eu2Ti2O7 thin films. Ceram. Int. 2018, 44 (8), 9479-9483. link
24. Jan Aubrecht, Pavel Peterka, Pavel Koška, Ondřej Podrazký, Filip Todorov, Pavel Honzátko, and Ivan Kašík, "Self-swept holmium fiber laser near 2100 nm," Opt. Express 25, 4120-4125 (2017)
25. Aubrecht, J., Kalvoda, L.: "Development of Ammonia Gas Sensor Using Optimized Organometallic Reagent," Journal of Sensors, Volume 2016, 58, http://dx.doi.org/10.1155/2016/8425758, 2016.
26. Koška, P., Peterka, P., Aubrecht, J., Podrazký, O., Todorov, F., Becker, M., Baravets, Y., Honzátko, P., and Kašík, I.: "Enhanced pump absorption efficiency in coiled and twisted double-clad thulium-doped fibers," Opt. Express 24(1):102-107, http://dx.doi.org/10.1364/OE.24.000102, 2016.
27. Peterka, P.,  Honzátko, P., Kašík, I., Podrazký, O., Todorov, F., Cajzl, J., Koška, P., Baravets, Y., Aubrecht, J., Mrázek, J.: "Thulium-doped fibers and fiber-optic components for fiber lasers at around 2 μm," Jemná mechanika a optika 60(5-6), 2015.
28. Martan, T., Aubrecht, J., Podrazký, O., Matějec, V., Kašík, I.: "Detection of hydrocarbons using suspended core microstructured optical fiber," Sensors and Actuators B: Chemical, http://dx.doi.org/10.1016/j.snb.2014.04.103, 2014.
29. Kasik, I., Podrazky, O., Mrazek, J., Cajzl, J., Aubrecht, J., Probostova, J., Peterka, P., Honzatko, P., Dhar, A.: "Erbium and Al2O3 nanocrystals-doped silica optical fibers," Bulletin of the Polish Academy of Sciences: Technical Sciences, 62 (4), DOI: 10.2478/bpasts-2014-0070, 2014.
30. Peterka, P., Honzátko, P., Koška, P., Todorov, F., Aubrecht, J., Podrazký, O., and Kašík, I.: "Reflectivity of transient Bragg reflection gratings in fiber laser with laser-wavelength self-sweeping," Opt. Express 22:30024-30031, http://dx.doi.org/10.1364/OE.22.030024, 2014.
31. Mrázek, J., Kašík, I., Procházková, L., Čuba, V., Aubrecht, J., Cajzl, J., Podrazký, O., Peterka, P., Nikl, M.: "Active optical fibers doped with ceramic nanocrystals," Advances in Electrical and Electronic Engineering 12(6):567-574, 2014.
32. Peterka, P., Honzátko, P., Todorov, F., Kasik, I., Aubrecht, J., Podrazký, O.: "Self-Q-switched regime of fiber lasers as a transition from self-induced laser line sweeping", Specialty Optical Fibers, SOF 2014, http://www.scopus.com/inward/record.url?eid=2-s2.0-84919772399&partnerID..., 2014.
33. Podrazký, O., Matějec, V., Mrázek, J., Martan, T., Aubrecht, J., Kašík, I.,: "Tapered optical fiber sensor for detection of pH in microscopic volumes," Sensors & Transducers 27, 312-318, 2014.
34. Matějec, V., Kašík, I., Podrazký, O., Aubrecht, J., Frank, M., Jelínek, M., Kubeček, V., "Preparation and characterization of bragg fibers for delivery of laser radiation at 1064 nm," Radioengineering, 22 (1), 2013.
35. Kasik, I., Mrazek, J., Podrazky, O., Seidl, M., Aubrecht, J., Pospisilova, M., Tobiska, P., Matejec, V., Kovacs, B., Markovics, A., Szili, M.: "Fiber- optic detection of chlorine in water," Sensors and Actuators: B 139 (1), 139-142, 2009.  
36. Kašík, I., Mrázek, J., Podrazký, O., Seidl, M., Aubrecht, J., Tobiška, P., Matějec, V., Kovács, B., Markovics, A., Szili, M.: "Preparation and characterization of thin transducer layers sensitive to free chlorine in water," Materials Science and Engineering C 28 (5-6), 842-847, 2008. 
37. Kalvoda, L., Aubrecht, J., Klepacek, R.: "Fiber Optic Detection of Ammonia Gas," Acta Polytechnica 46(2), 2006.

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. M. Kamrádek, I. Kašík, J. Aubrecht, Jan Mrázek, O. Podrazký, J. Cajzl, P. Varák, V. Kubeček, P. Peterka, P. Honzátko: „Holmium-doped optical fibers for efficient fiber lasers," Proc. SPIE 11355, Micro-Structured and Specialty Optical Fibres VI, 113550C (2020); doi:10.1117/12.2559176.
4. 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. 
5. Ali A. Jasim, J. Aubrecht, P. Peterka, M. Kamrádek, O. Podrazký, F. Todorov, I. Kašík and P. Honzátko: „Efficient Pump Absorption in Twisted Double Clad Thulium-Doped Fibers Drawn of CO2 Laser Shaped Preform,“ Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference, NSPEC Accession Number: 19148128, (2019), DOI: 10.1109/CLEOE-EQEC.2019.8871910.
6. A. Theodosiou, J. Aubrecht, Nithyanandan Kanagaraj, P. Peterka, K. Kalli, I. Kašík and P. Honzátko: „All-Fiber Mode-Locked Thulium Doped Fiber Laser Using a Novel Femtosecond Laser Inscribed 450 Tilted Fiber Grating,“ Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference, INSPEC Accession Number: 19127971, (2019), DOI: 10.1109/CLEOE-EQEC.2019.8871737. 
7. M. Kamrádek, J. Aubrecht, P. Peterka, O. Podrazký, P. Honzátko, J. Cajzl, J., Mrázek, V. Kubeček, I. Kašík, "Spectroscopic characterization of holmiumdoped optical fibers for fiber lasers," Proc. SPIE 11029, Micro-structured and Specialty Optical Fibres VI, 1102908 (2019); doi: 10.1117/12.2520880.
8. M. Kamrádek, I. Kašík, J. Aubrecht, J. Mrázek, O. Podrazký, J. Cajzl, P. Vařák, P. Peterka, P. Honzátko, "Holmiem dopované vláknové lasery", Laser 59 (2019).
9. A. Theodosiou, J. Aubrecht, P. Peterka, K. Kalli, "Femtosecond laser plane-by-plane Bragg gratings for monolithic Thuliumdoped fibre laser operating at 1970 nm ," Proc. SPIE 11029, Micro-structured and Specialty Optical Fibres VI, 110290F (2019); doi: 10.1117/12.2524911.
10. Mrázek, J., Kašík, I., Aubrecht, J.,  Podrazký, O.,  Cajzl, J., Peterka, P.  Nanocrystalline Ceramic Phosphors for High-Power Lasers Operating at 2μm.  In: 21st International Conference on Transparent Optical Networks (ICTON). 2019, p. 1-4.
11. J. Aubrecht, A. Theodosiou, P. Peterka, I. Kašík, F. Todorov, O. Moravec, P. Honzátko, K. Kalli, "Monolithic Er/ Yb double-clad fibre laser with FBG inscribed using the direct-write plane-byplane fs-laser inscription method," Proc. SPIE 10683, Fiber Lasers and Glass Photonics: Materials through Applications, 1068304 (2018); doi: 10.1117/12.2306522.
12. M. Kamrádek, I. Kašík, P. Peterka, J. Aubrecht, O. Podrazký, P. Honzátko, J. Mrázek, V. Kubeček, "Silica- and germanate-based rare earth doped glasses for fiber lasers," Proc. SPIE 10683, Fiber Lasers and Glass Photonics: Materials through Applications, 106832L (2018); doi: 10.1117/12.2306263.
13. J. Aubrecht, P. Peterka, P. Honzátko, O. Moravec, M. Kamrádek, I. Kašík: "Broadband ASE sources with flat output spectra without internal spectral flattening filter", Europhoton, Barcelona, Spain (2018).
14. Aubrecht, J., Peterka, P., Kašík, I., Podrazký, O., Cajzl, J., Benda, A., Baravets, Y., and Honzátko, P.: "Characterization and numerical modeling of holmium-doped fibers with various concentrations for fiber lasers, 20th Slovak-Czech-Polish Optical Conference on Wave and Quantum Aspects of Contemporary Optics, Jasná pod Chopkom, 2016.
15. Aubrecht, J., Peterka, P., Honzatko, P., Baravets, Y., Jelínek, M., et al.: "Characterization of holmium fibers with various concentrations for fiber laser applications around 2.1 μm," Proc. of SPIE, http://dx.doi.org/10.1117/12.2227618, 2016.
16. Aubrecht, J., Kalvoda, L., Fojtikova, J.: "Characterization of long-term stability of PDMS-based chemo-optical transducer driving distributed fiber optic sensor of ammonia gas," Proceedings of SPIE, http://dx.doi.org/10.1117/12.2236706, 2016.
17. Aubrecht, J., Kalvoda, L., Levinský, P., Fojtíková, J.: "The modification methods of polymer fiber cladding for sensing application," Proceedings of SPIE, 9450, art. no. 94500L, http://dx.doi.org/10.1117/12.2070462, 2015.
18. Aubrecht, J., Cajzl, J., Peterka, P., Honzátko, P., Koška, P., Baravets, Y., Becker, M., Podrazký, O., Todorov, F., and Kašík, I.: "Characterization of double-clad thulium-doped fiber with increased quantum conversion efficiency," Proc. of SPIE, http://dx.doi.org/10.1117/12.2179630, 2015.
19. Levinský, P., Kalvoda, L., Aubrecht, J., Fojtíková, J.: "Diffusion of ammonia gas in PDMS characterized by ATR spectroscopy, " Proceedings of SPIE, 9450, http://dx.doi.org/10.1117/12.2070372,  2015.
20. Podrazký, O., Kašík, I., Peterka, P., Aubrecht, J., Cajzl, J., Proboštová, J., Matějec, V.: "Preparation of optical fibers with non-circular cross-section for fiber lasers and amplifiers, " Proceedings of SPIE, art. no. 94501A, http://dx.doi.org/10.1117/12.2070351, 2015.
21. Mrázek, J., Nikl, M., Kašík, I., Podrazký, O., Aubrecht, J., Beitlerová, A: "Nanoparticle-doped radioluminescent silica optical fibers," Optical Fibers and Their Applications (SPIE) 9228, 2014.
22. Aubrecht J., Kalvoda L. "Development of absorption fiber optic sensor for distributed measurement of ammonia gas," Proceedings of SPIE, 8774, art.no.877417, http://dx.doi.org/10.1117/12.2017281, 2013.
23. Cajzl, J., Podrazky, O., Mrazek, J., Aubrecht, J., Matejec, V., Peterka, P., Nekvindová, P., Kasik I.: "The influence of nanostructured optical fibre core matrix on the optical properties of edfa," Proceedings of SPIE, 8775, 2013.
24. Matějec, V., Kašík, I., Podrazký, O., Aubrecht, J., Frank, M., Jelínek, M., Kubeček, V.: "Preparation and characterization of bragg fibers with air cores for transfer of laser radiation," Optics and Optoelectronics (SPIE) 8775, 2013.
25. Martan, T., Aubrecht, J., Podrazký, O., Kašík, I., Matějec, V., Kaňka, J.: "Microstructure optical fibres for detection of gaseous analytes," The International Society for Optical Engineering (SPIE) 8073, 2011. 
26. Pospíšilová, M., Aubrecht, J., Martan, T., Mrázek, J., Kašík, I., Matějec, V.: "Dependence of detected intensity of fluorescence of dye on optical fiber tapered tip diameter," The International Society for Optical Engineering (SPIE) 8073, 2011.
27. Martan, T., Pospíšilová, M., Aubrecht, J., Mrázek, J., Podrazký, O., Kašík, I., Matějec, V.: "Tapered optical fibres for local pH detection," Journal of Physics: Conference Series 206, 2010. 
28. Martan, T., Kašík, I., Podrazký, O, Mrázek, J., Pospíšilová, M., Aubrecht, J., Matějec, V., Kaňka, J.: "Local Detection of pH Using Optical Fibre Probes," Proc. 6th Journees Maghreb-Europe, Les Materiaux et Leurs Applications aux Dispositifs Capteurs (MADICA), 2008. 
29. Kašík, I., Mrázek, J., Podrazký, O., Seidl, M., Aubrecht, J., Pospíšilová, M., Tobiška, P., Matějec, V., Kovacs, B., Markovics, A., Szili, M.: "Detection of chlorine in water", 2008. 
30. Podrazký, O., Mrázek, J., Seidl, M., Kašík, I., Tobiška, P., Matějec, V., Martan, T., Aubrecht, J.: "Optical principle of pH measurement for detection of auxin flow through cellular membrane," In Proc. SPIE, 2007.