NATIONAL INSTITUTE for LASER, PLASMA and RADIATION PHYSICS
  LABORATORY of SOLID-STATE QUANTUM ELECTRONICS

CONTRACT 208 / 01.10.2015; PN-II-RU-TE-2014-4-2443
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TITLU:                                 Materiale monocristaline si ceramici policristaline alternative pentru laseri in vizibil

TITLE:                                 Single crystalline and alternative polycrystalline ceramic materials for visible lasers
ACHRONIM:                        CRYCERVIS

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FUNDED BY:                      
 UEFISCDI, Ministry of Education, Research, Youth and Sport, Romania
FINANTARE :                        Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii şi Inovarii (UEFISCDI), Ministerul Educatiei, Cercetarii, Tineretului si Sportului, Romania
PROJECT MANAGER:           Dr. Cristina GHEORGHE
DIRECTOR DE PROIECT:       Dr. Cristina GHEORGHE
Email:                                   cristina.gheorghe@inflpr.ro
                                            cristina_gheorghe2002@yahoo.com
 

PROJECT DURATION:           October 2015 - September 2017
DURATA PROIECTULUI:        Octombrie 2015 - Septembrie 2017

PROJECT LEADER:              National Institute for Laser, Plasma and Radiation Physics, Magurele, Bucharest, Romania
CONDUCATOR PROIECT:
  
  Institutul National de Cercetare-Dezvoltare pentru Fizica Laserilor, Plasmei si Radiatiei, Magurele, Bucuresti, Romania

Contract value:                      550.000 lei

Valoare contract:                   550.000 lei

The research team:                GHEORGHE Cristina Petruta, PhD

Echipa de cercetare:              GHEORGHE Lucian Marian, PhD

                                            TOMA Octavian, PhD

                                            ACHIM Alexandru, PhD

                                            VOICU Flavius Marian, PhD student

                                            HAU Stefania, PhD student

                                            CROITORU Gabriela, PhD student

                                            CHIRCUS Laurentiu, sub-engineer 

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ABSTRACT. Based on the most recent fundamental and technological advances, the project aims to identify and develop new laser materials with controllable properties for efficient generation of laser emission in the visible (VIS) spectral range. The research will be directed toward calcium-niobium-gallium-garnet (CNGG) and calcium-lithium-niobium-gallium- garnet (CLNGG) intrinsic disordered materials, as single crystals and alternative polycrystalline ceramic materials, mainly doped with RE3+ ions (RE = Pr, Sm, Tb, Dy) and sensitized with appropriate lanthanide ions.

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OBJECTIVES

2015. Value: 30.000 lei
Objective I. Disordered RE3+-doped and sensitized CNGG and CLNGG single crystalline laser materials. / Preliminary.
Objective II. Disordered RE3+-doped and co-doped CNGG and CLNGG polycrystalline laser ceramics.
Preliminary.

2016. Value: 350.000 lei
Objective I. Disordered RE3+-doped and sesitized CNGG and CLNGG single crystalline laser materials. / Partially.
Objective II. Disordered RE3+-doped and co-doped CNGG and CLNGG polycrystalline laser ceramics.
Partially.

2017. Value: 170.000 lei
Objective I. Disordered RE3+-doped and sesitized CNGG and CLNGG single crystalline laser materials. / Final.
Objective II. Disordered RE3+-doped and co-doped CNGG and CLNGG polycrystalline laser ceramics.
Final.
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RESULTS IN 2015
Objective I. Disordered RE3+-doped and sensitized CNGG and CLNGG single crystalline laser materials. / Preliminary.
Objective II. Disordered RE3+-doped and co-doped CNGG and CLNGG polycrystalline laser ceramics.
Preliminary.

Activities:
I.1 High-resolution spectroscopic characterization. / Preliminary results.

Obtained results:
During this stage were achieved all the objectives and activities specified in the project. We have identified new luminescent systems based on the emission in the visible domain of RE3+ (Sm, Dy, Pr, Tb) ions doped in host materials with intrinsic disorder, type garnet calcium-niobium-gallium (CNGG) and calcium-lithium-niobium-gallium (CLNGG).
Thus:

 Samples of CNGG and CLNGG doped with Sm (0.1, 1 and 3 at.%), Dy (0.1, 1 and 3 at.%), Pr (0.1, 1 and 3 at.%) and Tb (0.1, 1 and 3 at.%) ions, using solid state reaction technique.
 Based on high-resolution spectroscopic measurements at 300 and 10 K (absorption, emission and emission kinetics) new spectral data about these ions RE3+ (Sm, Dy, Pr, Tb) doped CNGG and CLNGG were obtained.
The obtained preliminary spectral data confirms that selected doped ions have been successfully incorporated into the proposed materials, allowing us to continue the research with the growth of the single crystals and obtaining the ceramics of CNGG and CLNGG doped RE3+ (Sm, Dy, Pr, Tb).

Raportul stiintific pe anul 2015 este disponibil aici: | 2015
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RESULTS IN 2016
Objective I. Disordered RE3+-doped and sesitized CNGG and CLNGG single crystalline laser materials. / Partially.
Objective II. Disordered RE3+-doped and co-doped CNGG and CLNGG polycrystalline laser ceramics. / Partially.

Activities:
I.1 Single crystals growth by Czochralski method.
I.2 High resolution optical spectroscopy characterization.
I.3 Optimization of visible laser emission.
II.1 Obtaining of polycrystalline transparent ceramics.
II.2
High resolution optical spectroscopy characterization.

Obtained results
During this stage were achieved all the objectives and activities specified in the project.
Single crystals of Sm:CNGG and Sm:CLNGG with 3.4 and 5 at.% Sm3+ ions and Dy:CNGG and Dy: CLNGG with 3.4 and 5 at.% Dy3+ ions were grown by Czochralski method.
Ceramics samples of CNGG and CLNGG doped with Sm (0.1, 1 and 3 at.%) ions, were obtained using vacuum reactive sintering method.
Ceramics samples of CNGG and CLNGG doped with Sm3+ ions and sensitized with Ce3+ ions with different concentration of doping ions were obtained using solid state reaction technique.
Ceramics samples of CNGG and CLNGG doped with Dy3+ ions and sensitized with Ce3+ ions with different concentration of Ce3+ ions were obtained using solid state reaction technique.
High resolution optical spectroscopy at different temperature was applied to obtain static and dynamic properties of Sm3+ ions doped CNGG and CLNGG single crystals. The absorption spectra of Sm3+ at room temperature were analyzed on the basis of the Judd-Ofelt theory in order to calculate the line strengths of Sm3+ electric dipole transitions. The intensity J-O parameters obtained for Sm doped both crystals were estimated and used to determine the radiative transition rates, fluorescence branching ratios and radiative lifetime. Partial energy levels of Sm3+ have been established based on the low temperature absorption and emission spectra. The experimentally integrated cross-sections for the 4G5/26H7/2 transition at 615 nm were fund to be 0.8710-21 cm2 for CNGG and 110-21 cm2 in the case of CLNGG.
High resolution optical spectroscopy at different temperature was applied to obtain static and dynamic properties of Dy3+ ions doped CNGG and CLNGG single crystals. Partial energy levels of Dy3+ have been established based on the low temperature absorption and emission spectra.
Ceramic samples of CLNGG doped with 0.1 at. % Sm ions and co-doped with 0.01 - 0.1 at.% Ce3+ ions were prepared and investigated to establish Ce3+ ions concentration in order to obtain efficient energy transfer from Ce→Sm and increase the emission of Sm ions in visible domain. The emission spectra of (x Ce, 0.01 Sm):CLNGG at room temperature were analyzed and was established that CLNGG sample doped with of 0.1 at.% Sm + 0.02 at.% Ce had the most intense Sm3+ emission lines.
Ceramic samples of CLNGG doped with 0.02 at.% Ce and co-doped with 1 - 10 at % Sm were prepared and investigated in order to establish the best Sm3+ ions concentration before concentration quenching mechanism appear. The emission spectra of (0.02 Ce, x Sm):CLNGG at room temperature were analyzed and was established that CLNGG sample doped with of 0.02 at.% Ce + 3 at.% Sm had the most intense Sm3+ emission lines.
Ceramic samples of CLNGG doped with 0.1 at.% Dy3+ ions and co-doped with 0.01 - 0.1 at.% Ce ions were prepared and investigated to establish Ce3+ ions concentration in order to obtain efficient energy transfer from Ce→Dy and increase the emission of Dy3+ ions in visible (blue and yellow) domain. The emission spectra of (x Ce, 0.01 Dy):CLNGG at room temperature were analyzed and was established that CLNGG sample doped with of 0.1 at.%Dy + 0.9 at.% Ce had the most intense Dy3+ emission lines.
Raportul stiintific pe perioada 2015-2016 este disponibil aici: | 2016

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RESULTS IN 2017
Objective I. Disordered RE3+-doped and sesitized CNGG and CLNGG single crystalline laser materials. / Final.

Objective II. Disordered RE3+-doped and co-doped CNGG and CLNGG polycrystalline laser ceramics. / Final.

Activities
I.1
     Single crystals growth by Czochralski method.
I.2     High resolution optical spectroscopy characterization.
I.3     Optimization of visible laser emission.
II.1    Obtaining of polycrystalline transparent ceramics.
II.2    High resolution optical spectroscopy characterization.
II.3    Optimization of visible laser emission. / Partial
II.4
    Optimization of visible laser emission. / Final

Rezultate etapa
- Probe monocristaline si ceramici policristaline de tip CNGG si CLNGG co-dopate cu ioni RE3+ pentru masuratori spectroscopice;
- Montaje si date spectrale noi;
- Modelarea datelor si determinarea parametrilor caracteristici;
- Date noi spectrale si de cinetica emisiei.
- Analiza matematica a datelor experimentale.
- Evaluarea eficientei de emisie laser in sisteme sensibilizate.
- Sinteza datelor in vederea publicarii in reviste cotate ISI.

- Prezentarea rezultatelor la Conferinte Internationale si publicarea in reviste cotate ISI
.

Obtained results
During this stage were achieved all the objectives and activities specified in the project.

- Single crystals of Pr:CNGG and Pr:CLNGG doped with (3 and 5) at.% Pr3+ ions and Tb:CNGG and Tb: CLNGG doped with (3 and 5) at.% Tb3+ ions were grown by Czochralski method.

- Single crystals of CNGG and CLNGG doped with Pr3+ (3 and 5 at.%) were characterized by high resolution spectroscopy. From the absorption and emission spectra at 10K, a partial level scheme of Pr3+ ion was extracted.

- Single crystals of CNGG and CLNGG doped with Tb3+ (5 at.%) were characterized by high resolution optical spectroscopy. From the absorption and emission spectra at 10K, a partial level scheme of Tb3+ ion was extracted.

- Correlation of spectral data with structural models, evaluation of spectroscopic parameters of interest for laser emission in VIS was made based on the obtained data.

- Co-doped samples of Tb3+, Ce3+: CLNGG ceramic were obtained by solid state reaction. CLNGG samples were doped with (0.1 at%) Tb3+ and co-doped with Ce3+ ions from 0.01 0.1 at%. Based on spectroscopic investigation, it was determined that the most effective combination of dopants was for 0.06 at% Tb, 0.03 at% Ce doped CLNGG sample.

- Transparent ceramic samples of CNGG and CLNGG doped with Pr, Sm, Dy ions were obtained. The ceramics were investigated by X-ray diffraction and optical spectroscopy. From structural and spectroscopic point of view, transparent ceramics are identical to the corresponding CNGG and CLNGG single crystals doped with RE3+. CNGG and CLNGG transparent ceramics doped with Pr, Sm, Dy ions were obtained for the first time in this project as well as in the ECS laboratory in INFLPR.
The new data obtained (spectroscopic and laser data) will be the subject of new papers, a series of manuscripts being in progress.

 
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DISSEMINATION OF THE RESULTS

I. ARTICLES PUBLISHED IN ISI JOURNALS
1. C. Gheorghe, A. Lupei, S. Hau, F. Voicu, L. Gheorghe, A. M. Vlaicu, "Compositional dependence of optical properties of Sm3+-doped Y3ScXAl5-XO12 polycrystalline ceramics," J. Alloys & Comp. 683, 547-553 (2016). IF 3.014.
2. C. Gheorghe, S. Hau, L. Gheorghe, F. Voicu, M. Greculeasa, A. Achim, M. Enculescu, “Optical properties of Sm3+ doped Ca3(Nb,Ga)5O12 and Ca3(Li,Nb, Ga)5O12 single crystals,” J. Lumin. 186, 175-182 (2017). IF = 2.693.
3. I.О. Vorona, R.P. Yavetskiy, A.G. Doroshenko, S.V. Parkhomenko, A.V. Tolmachev, V.N. Baumer, D.Yu. Kosyanov, V.I. Vovna, V.G. Kuryavyi, M. Greculeasa, L. Gheorghe, S. Hau, C. Gheorghe, G. Croitoru, “Structural-phase state and lasing of 5-15 at% Yb3+:Y3Al5O12 optical ceramics,” J. Eur. Cer. Soc. 37(13) (2017) 4115-4122. IF = 3.411.

II. COMMUNICATIONS AT INTERNATIONAL CONFERENCES

1. F. Voicu, L. Gheorghe, M. Greculeasa, A. Achim, C. Gheorghe, S. Hau, “Growth and optical properties of Sm3+ doped Ca3(Nb,Ga)5O12 and Ca3(Li,Nb, Ga)5O12 single crystals,” TIM 17 Physics Conference, 25 - 27 May 2017, Timisoara, Romania; poster CM-P08.
2. S. Hau, C. Gheorghe, L. Gheorghe, I. Porosnicu, A. Crisan, “Luminescence properties and energy transfer of Sm3+ and Dy3+ co-doped Ca3(Li,Nb, Ga)5O12: Ce3+ novel phosphors under UV excitation,” Timisoara, Romania, 25-27 Mai 2017; poster P02.
3. L. Gheorghe, F. Voicu, M.Greculeasa, A. Achim, F. Khaled, P. Loiseau, G. Aka, S. Hau, C.Gheorghe, G Croitoru, “Pure and Yb-doped LaxGdySc4-x-y(BO3)4 incongruent borates type crystal: czochralski growth, nonlinear properties and laser performances,” TIM 17 Physics Conference, 25 - 27 May 2017, Timisoara, Romania; invited talk CM-I01.
4. I. O. Vorona, R.P. Yavetskiy, M.V. Dobrotvorskaya, A.G. Doroshenko, S.V. Parkhomenko, A.V. Tolmachev, L. Gheorghe, C. Gheorghe, S. Hau, “Solid-state sintering and luminescent properties of Yb3+, Er3+:YAG transparent ceramics,” International Conference on Oxide Materials for Electronic Engineering - Fabrication, Properties and Applications, OMEE-2017, May 29 - June 2, 2017, Lviv, Ukraine; poster Mo-P59.
5. I. O. Vorona, R. P. Yavetskiy, A. G. Doroshenko, S. V. Parkhomenko, A. V. Tolmachev, L. Gheorghe, M. Greculeasa, C. Gheorghe, S. Hau, and G. Croitoru, “Nd3+:YAG Ceramic Materials with Efficient Laser Emission under Diode-Laser Pumping,” LIC 2017, 20-23 June 2017, Bucharest, Romania; poster LWA5.4.

6. F. Voicu, L. Gheorghe, A. Achim, C. Gheorghe, S. Hau, P. Loiseau, F. Khaled, G. Aka, G. Croitoru, “Optical and laser performances of Yb:LGSB nonlinear optical crystal,” ROCAM 2017, 11-14 July 2017, Bucharest, Romania; poster.

III. PhD THESIS

In 2018, on the basis of the results obtained in the framework of the project, Mrs. HAU Stefania, PhD student will sustain her PhD thesis titled "Investigation of emission in visible domain of rare earth ions in monocrystals and polycrystalline ceramics ". We note that Mrs. HAU Stefania is member of the project team as PhD student. ____________________________________________________________________________________________________________________________________________________________________________
Laboratory of Solid-State Quantum Electronics