CeMiLAP

Ceramiche Microstrutturate trasparenti per applicazioni Laser di Alta Potenza: sviluppo e validazione

Principal investigator: Jan Hostaša

Involved personnel: Valentina Biasini, Andreana Piancastelli, Laura Esposito

Start date: 09/03/2015
Duration: 36 months
Total funding: 314 649 €
Call/Action: PNRM Program, Italian Ministry of Defence
Role of CNR-ISTEC: Coordinator
Project consortium: CNR-ISTEC, CNR-INO

Transparent Yb³⁺ doped materials have proved to be essential for the production of high power and high efficiency diode pumped lasers with emission in the near infrared (typically in the 1010-1080 nm region). This is primarily due to the structure of the energy levels of ytterbium, that, thanks to the low quantum defect, allows for higher efficiencies compared to, for example, neodymium lasers. In addition, the presence of a wide absorption band allows a  more efficient and stable pumping with semiconductor lasers than the previously mentioned neodymium.

Besides, the use of polycrystalline ceramic materials as hosts allows to produce large laser active elements with optimized performances.

At international level, Yb:YAG and Nd:YAG is considered the ceramic laser material that has reached the highest maturity, with laser performances similar to the corresponding monocrystalline material. The interest in scientific and technological research is thus shifting towards new materials, including the so-called sesquioxides such as lutetium (Lu₂O₃) and scandium oxides (Sc₂O₃), whose thermomechanical properties appear very promising for the realization of high power laser sources.

In this context, the CeMiLAP project is aimed at the development of manufacturing technologies for the production of Yb-doped transparent materials (YAG, Lu₂O₃ and Sc₂O₃) for the achievement of large laser elements with non-uniform and controlled doping distributions, in selected geometries and structures optimized for the management of thermal loads in specific pumping and cooling geometries.

In particular, the following objectives are pursued:

• Optimization of the production process for Yb:YAG transparent ceramics
• Transfer and adjustment of the production techniques already developed for YAG to the production of transparent ceramics with Lu₂O₃ and Sc₂O₃ composition and with Yb doping;
• Modelling of dopant distributions suitable for the reduction of thermal gradients and the derived thermal effects like thermal lensing
• Development of new technologies for the production of ceramic samples with non-uniform doping distribution;
• Dimensional scale-up of the production processes, aimed at the realization of the large samples required for high power laser systems.

Publications

• G. Toci, J. Hostaša, B. Patrizi, V. Biasini, A. Pirri, A. Piancastelli, M. Vannini.: Fabrication and laser performances of Yb:Sc₂O₃ transparent ceramics from different combination of vacuum sintering and hot isostatic pressing conditions. Journal of the European Ceramic Society 40 (2020) 881-886.
• J. Hostaša, A. Piancastelli, G. Toci, M. Vannini, V. Biasini.: Transparent layered YAG ceramics with structured Yb doping produced via tape casting. Optical Materials 65 (2017) 21-27.
• J. Hostaša, V. Biasini, A. Piancastelli, M. Vannini, G. Toci.: Layered Yb:YAG ceramics produced by two different methods: processing, characterization, and comparison. Optical Engineering 55 (2016) 087104.
• J. Hostaša, L. Esposito; V. Biasini; A. Piancastelli; M. Vannini; G. Toci.: Layered Yb:YAG ceramics produced by two different methods: processing, characterization and comparison. SPIE Proceedings 9726 (2016) 97261M-1.
• G. Toci, A. Lapucci, M. Ciofini, L. Esposito, J. Hostaša, L. A. Gizzi, L. Labate, P. Ferrara, A. Pirri, M. Vannini.: Laser and optical properties of Yb:YAG ceramics with layered doping distribution: design, characterization and evaluation of different production processes. SPIE Proceedings 9726 (2016) 97261P-1.