Novel silica-based Ho -doped nanomaterials for 2-μm-class fibre laser research

Sponsor: Czech Science Foundation

Principal investigator: Dr. Ing. Ivan Kašík

Members: Ing. Jan Aubrecht, Ph.D.; Dr. Ing. Pavel Honzátko; Ing. Jan Mrázek, Ph.D.; Ing. Pavel Peterka, Ph.D.; Ing. Ondřej Podrazký, Ph.D.;

From: 2014-01-01

To: 2016-12-31

Novel approaches to preparation of original nanocrystalline materials (RE- doped YAGs and titanates, aluminates) were elaborated. Embedding of such nanocrystals into silica matrix by elaborated nanoparticle-doping method resulted in verification of goal of the project. This goal was based on hypothesis that ceramic nanocrystals under certain conditions may enhance luminescent properties of RE in silica-based glass matrix (E.g. fluorescence lifetime) keeping its high transparency. Silica optical fibers based on such Ho and Tm -doped materials were successfully drawn and used in fiber lasers operating efficiently in wide spectral range around/beyond 2 μm. Phase separation (increasing background losses) were effectively mitigated in RE and Al203 doped fibers (of suitable doping level) and clustering effects of REs negatively influencing laser slope efficiency were decreased (by implementation of nanocrystals). A mechanism of ceramic nanocrystals acting in RE -doped silica fibers was interpreted. On the basis of numerical modelling of DC fibes an original knowledge that the absorption can be even higher than the ideal limit given by the ratio of the core and cladding areas was discovered. The results of the project supported engagement of the research team in international collaboration with leading teams in the field (E.g., ORC Southampton, COST MP1401 partners) and recruitment of new PhD students (Kamradek, Vytykacova, Cajzl, Koska, Bohacek). Results achieved with the support of the project were published within 29 outputs: 5 impacted journals (Jimp), 5 conference WOS registered proceeding (D), 1 reviewed journal (Jrec), 2 invited lectures, 11 oral conference presentations, 4 conference posters and 1 publication in edition of CAS “Science around us”.Nearly 10 years has passed since publishing of the pioneering work [Podrazky, Kasik, Pospisilova, Matejec, Use of alumina nanoparticles for preparation of erbium-doped fibers, 2007 IEEE LEOS Annual Meeting Conf. Proc. 1-2, 2007, 246-247]. Number of worldwide leading laboratories and centers of academic, military and commercial research has started to deal with this issue since that time. The results achieved within this project crowned a bit the fundamental research stage in this field and can serve as a solid fundament for following applied research.

References:

1. P. Honzátko, Y. Baravets, I. Kašík, O. Podrazký, Wideband thulium-holmium-doped fiber source with combined forward and backward ASE at 1600- 2300 nm spectral band, Optics Letters 39 (2014) 3650-3653
2. P. Koska, P. peterka, Numerical analysis of pump propagation and absorption in specially tailored double-clad rare-earth doped fiber, Optical and Quantum Electronics 47 (2015) 3181-319
3. P. Koška, P. Peterka, V. Doya, Numerical modeling of pump absorption in coiled and twisted double-clad fibers, IEEE J. Selected Topics in Quantum Electron, 22 (2), March/April 2016, Article No. 4401508
4. I. Kašík, P. Peterka, J. Mrázek, P. Honzátko, Silica optical fibers doped with nanoparticles for fiber lasers and broadband sources, Current Nanoscience 12 (2016) 277-290
5. J. Sotor, M. Pawliszewska, G. Sobon, P. Kaczmarek, A. Przewolka, I. Pasternak, J. Cajzl, P. Peterka, P. Honzátko, I. Kašík, W. Strupinski, K.Abramski, All-fiber Ho-doped mode-locked oscillator based on a graphene saturable absorber, Optics Letters 41 (2016) 2592-259