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


CONTRACT PCE 49 / 05.02.2021 (PN-III-P4-ID-PCE-2020-2203); PNCDI III - PROGRAMUL 4 - CERCETARE FUNDAMENTALA SI DE FRONTIERA
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TIP PROIECT:                    PROIECT DE CERCETARE EXPLORATORIE

TITLU:                                CRISTALUL BIFUNCTIONAL AVANSAT Nd:LYSB PENTRU SURSE LASER NOI SI EFICIENTE IN DOMENIILE SPECTRALE INFRAROSU APROPIAT SI VIZIBIL
TITLE:                                advances bifunctional Nd:LYSB crystal for new and efficient laser sources in the  NEAR-INFRARED AND VISIBLE spectral ranges

PROJECT ACRONYM:      BILAS

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FUNDED BY:                          UEFISCDI, Ministry of Education and Scientific Research, Romania
FINANTARE :                          Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii şi Inovarii (UEFISCDI), Ministerul Cercetarii, Inovarii si Digitalizarii, Romania
PROJECT MANAGER:           Dr. Lucian Marian GHEORGHE
DIRECTOR DE PROIECT:      Dr. Lucian Marian GHEORGHE
Email:                                      lucian.gheorghe@inflpr.ro  

PROJECT DURATION:          January 2021 - December 2023
DURATA PROIECTULUI:       Ianuarie 2021 - Decembrie 2023

PROJECT LEADER:              National Institute for Laser, Plasma and Radiation Physics, Magurele 077125, Ilfov, Romania
CONDUCATOR PROIECT:    Institutul National de Cercetare-Dezvoltare pentru Fizica Laserilor, Plasmei si Radiatiei, Magurele 077125, Ilfov, Romania

Contract value:                      1.198.032 RON

Valoare contract:                   1.198.032 RON

The research team:             GHEORGHE Lucian-Marian, PhD                 CS I

Echipa de cercetare:           PAVEL Nicolaie, PhD                                     CS I

                                            GHEORGHE Cristina-Petruta, PhD               CS II

                                            STANCIU George, PhD                                 CS III

                                            HAU Stefania, PhD                                        CS

                                            VOICU Flavius-Marian                                   CS

                                            BRANDUS Catalina-Alice                              CS

                                            GRECULEASA Madalin, PhD student           ACS

                                            BROASCA Alin-Constantin, PhD student      ACS

                                            CHIRCUS Laurentiu, engineer

                                            NAE Gheorghe, technician
 

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● The general objective of this project is to develop new bifunctional laser and NLO crystals for obtaining of efficient laser sources in the NIR (~1 μm) and VIS (~0.5 μm) ranges, based on direct laser emission and SFD processes, respectively. The project proposal is highly complex and multidisciplinary connecting many fields of physics, chemistry, crystal growth and machining, optical spectroscopy, laser experiments, as well as applicative outcomes.

● The project is structured in two specific objectives:
O1. Development of highly efficient Nd:LYSB crystals for solid-state lasers in the 1 μm spectral range;
O2. Development of high-efficiency Nd:LYSB SFD crystals in the green (~0.5 μm) spectral range.

1. STAGE I. January - December 2021
● Development of highly efficient Nd:LYSB crystals for solid-state laser sources in the 1 μm spectral range. PARTIAL 
2. STAGE II. January - December 2022
● Development of highly efficient Nd:LYSB crystals for solid-state laser sources in the 1 μm spectral range. FINAL 
3. STAGE III. January - December 2023
● Development of high-efficiency Nd:LYSB SFD crystals in the green spectral range (~0.5 μm).
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REZULTATE OBTINUTE
OBTAINED RESULTS
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1. ETAPA I. Ianuarie - Decembrie 2021
Dezvoltarea cristalelor Nd:LYSB foarte eficiente pentru surse laser cu corp solid in domeniul spectral 1 μm. PARTIAL.
Activitati specifice
I.1. Rafinarea compozitionala, cresterea cristalelor Nd:LYSB, caracterizarea proprietatilor NLO.
I.2. Caracterizarea spectroscopica de inalta rezolutie a cristalelor Nd:LYSB.

I.3. Experimente laser pe cristalele Nd:LYSB.

Obiectivele specifice etapei I a proiectului BILAS au fost indeplinite integral.
● Rafinarea compozitionala, cresterea cristalelor Nd:LYSB, caracterizarea proprietatilor NLO.
O gama larga de compusi de tip La1-xYxSc3(BO3)4 - LYSB si Nd:LYSB au fost sintetizati prin metoda reactiei in stare solida si au fost optimizati toti parametrii ce intervin in tratamentul termic de sinterizare al compusilor respectivi. Pe baza rezultatelor experimentale obtinute pe compusii LYSB au fost selectate doua compozitii ale matricei gazda pentru cresterea prin metoda Czochralski a cristalelor nestoichiometrice LYSB dopate cu ioni Nd3+. Intr-o prima etapa, concentratia de ioni Nd3+ a fost fixata ca fiind 5 at.%. In urma optimizarii parametrilor de crestere (montajul termic, vitezele de tragere si rotatie, directia de crestere si rata de racire la temperatura camerei) au fost crescute cristale Nd:LYSB transparente, nehigroscopice si stabile din punct de vedere chimic. Proprietatile optic neliniare (NLO) ale cristalului Nd:LYSB de ce mai buna calitate optica au fost investigate pe baza masuratorilor de indici de refractie. Masuratorile au fost realizate folosind metoda deviatiei minime intr-o prisma decupata din cristalul crescut.
● Caracterizarea spectroscopica de inalta rezolutie a cristalelor Nd:LYSB.
Spectrele de absorbtie si emisie ale ionilor Nd3+ in cristalul 5 at.% Nd:LYSB au fost inregistrate in lumina polarizata, la temperatura camerei (300 K) și temperaturi joase (10 K). Cinetica emisiei nivelului 4F3/2 al ionilor Nd3+ dopati in cristalul Nd:LYSB a fost masurata la 300 K cu excitare la 808 nm si analizata in termenii unui singur centru de emisie. 
● Experimente laser pe cristalele Nd:LYSB.
Performantele de emisie laser in domeniul spectral 1.06 μm ale cristalului 5 at.% Nd:LYSB au fost caracterizate in regim de functionare in unda quasi-continua.

1. STAGE I. January - December 2021

Development of highly efficient Nd:LYSB crystals for solid-state laser sources in the 1 μm spectral range. PARTIAL
Specific activities
I.1. Compositional refinement, growth of Nd:LYSB crystals, characterization of NLO properties.
I.2. High-resolution spectroscopic characterization of Nd:LYSB crystals.
I.3. Laser experiments on Nd:LYSB crystals.

The specific objectives of stage I of the BILAS project have been fully met.
● Compositional refinement, growth of Nd:LYSB crystals, characterization of NLO properties.
A wide range of compounds of La1-xYxSc3(BO3)4 - LYSB and Nd:LYSB - type were synthesized by the solid-state reaction method and all the parameters involved in the heat sintering treatment of these compounds were optimized. Based on the experimental results obtained on LYSB compounds, two compositions of the host matrix were selected for the growth by the Czochralski method of non-stoichiometric LYSB crystals doped with Nd3+ ions. In a first step, the Nd3+ ions concentration was fixed at 5%. After optimizing the growth parameters (thermal assembly, pulling and rotation rates, growth direction, and cooling rate to room temperature), transparent, non-hygroscopic, and chemically stable Nd:LYSB crystals were grown. The nonlinear optical (NLO) properties of the best optical quality Nd:LYSB crystal were investigated on the basis of refractive index measurements. The measurements were performed using the minimum deviation method in a prism cut from the grown crystal.
● High-resolution spectroscopic characterization of Nd:LYSB crystals.
The absorption and emission spectra of Nd3+ ions in the 5 at.% Nd: LYSB crystal were recorded in polarized light at room temperature (300 K) and low temperatures (10 K). The emission kinetics of the 4F3/2 level of Nd3+ ions doped in the Nd:LYSB crystal was measured at 300 K with excitation at 808 nm and analyzed in terms of a single emission center.
● Laser experiments on Nd:LYSB crystals.
The laser emission performances in the 1.06 μm spectral range of the 5 at.% Nd:LYSB crystal were characterized in quasi-continuous-wave operation regime.

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2. ETAPA II. Ianuarie - Decembie 2022
Dezvoltarea cristalelor Nd:LYSB foarte eficiente pentru surse laser cu corp solid in domeniul spectral 1 μm. FINAL.

Activitati specifice
II.1. Rafinarea compozitionala, cresterea cristalelor Nd:LYSB, caracterizarea proprietatilor NLO.
II.2. Caracterizarea spectroscopica de inalta rezolutie a cristalelor Nd:LYSB.
II.3. Experimente laser pe cristalele Nd:LYSB.

Obiectivele specifice etapei II a proiectului BILAS au fost indeplinite integral.
● Rafinarea compozitionala, cresterea cristalelor Nd:LYSB, caracterizarea proprietatilor NLO.
Pe baza rezultatelor obtinute in cadrul etapei anterioare a proiectului (Etapa I), compozitia nestoichiometrica La0.725Nd0.05Y0.475Sc2.75(BO3)4 a fost selectata ca si compozitie chimica a materiilor prime (compozitie initiala a topiturii) pentru cresterea prin metoda Czochralski a cristalelor de tip Nd:LYSB cu compozitie optimizata pentru obtinerea de emisie laser eficienta in domeniul spectral 1 μm. Au fost optimizate directia de crestere, vitezele de tragere si rotatie si rata de racire a cristalelor Nd:LYSB cu compozitie chimica a materiilor prime La0.725Nd0.05Y0.475Sc2.75(BO3)4. Cristalele obtinute sunt transparente, nehigroscopice si stabile chimic, avand dimensiuni de aproximativ 10 - 12 mm in diametru si 25 - 30 mm in lungime. Compozitia chimica a cristalului de cea mai buna calitate optica a fost determinata ca fiind La0.772Nd0.046Y0.287Sc2.895(BO3)4 (4.6 at.% Nd:LYSB).
● Caracterizarea spectroscopica de inalta rezolutie a cristalelor Nd:LYSB.
Proprietatile structurale si optic neliniare (NLO) ale cristalului uniaxial negativ 4.6 at.% Nd:LYSB au fost determinate si analizate. Proprietatile spectroscopice ale cristalului 4.6 at.% Nd:LYSB au fost de asemenea investigate prin masuratori de spectroscopie optica de inalta rezolutie si corelate cu proprietatile NLO.
● Experimente laser pe cristalele Nd:LYSB.
Pentru evaluarea performantelor laser in domeniul NIR ale cristalului 4.6 at.% Nd:LYSB, au fost efectuate experimente laser in regim de functionare quasi-continuu pe probe din cristal neacoperite antireflex la lungimile de unda de pompaj si respectiv de emisie laser. Cea mai mare panta a eficientei de emisie laser (ηsa) la 1.06 μm a fost ηsa = 0.63, fiind similara cu eficientele de emisie ale mediilor active laser de tip Nd:YAG acoperite antireflex. Acest fapt demonstreaza ca 4.6 at.% Nd:LYSB constituie un model experimental si functional de cristal laser cu emisie foarte eficienta in domeniul spectral 1 μm, care permite obtinerea de surse laser eficiente in domeniul 1 μm bazate pe cristalul 4.6 at.% Nd:LYSB.

2. STAGE II. January - December 2022
Development of highly efficient Nd:LYSB crystals for solid-state laser sources in the 1 μm spectral range. FINAL.
Specific activities
II.1. Compositional refinement, growth of Nd:LYSB crystals, characterization of NLO properties.
II.2. High-resolution spectroscopic characterization of Nd:LYSB crystals.

II.3. Laser experiments on Nd:LYSB crystals.

The specific objectives of stage II of the BILAS project have been fully met.
● Compositional refinement, growth of Nd:LYSB crystals, characterization of NLO properties.
Based on the results obtained in the previous stage of the project (Stage I), the non-stoichiometric composition La0.725Nd0.05Y0.475Sc2.75(BO3)4 (the initial composition of the melt) was selected as the chemical composition of the raw materials for the Czochralski growth of Nd:LYSB-type crystals with optimized composition to obtain efficient laser emission in the 1 μm spectral range. The growth direction, pulling and rotation rates, and cooling rate of Nd:LYSB crystals with the chemical composition of raw materials La0.725Nd0.05Y0.475Sc2.75(BO3)4 were optimized. The obtained crystals are transparent, non-hygroscopic, and chemically stable, having dimensions of approximately 10 - 12 mm in diameter and 25 - 30 mm in length. The chemical composition of the best optical quality crystal was determined to be La0.772Nd0.046Y0.287Sc2.895(BO3)4 (4.6 at.% Nd:LYSB).
● High-resolution spectroscopic characterization of Nd:LYSB crystals.
The structural and nonlinear optical (NLO) properties of the uniaxial negative 4.6 at.% Nd:LYSB crystal were determined and analyzed. The spectroscopic properties of the 4.6 at.% Nd:LYSB crystal were also investigated by high-resolution optical spectroscopy measurements and correlated with the NLO properties.
● Laser experiments on Nd:LYSB crystals.
In order to evaluate the laser performance in the NIR range of the 4.6 at.% Nd:LYSB crystal, laser experiments were performed in quasi-continuous operating mode on crystal samples not anti-reflex coated at the pumping and laser emission wavelengths, respectively. The highest slope of the laser emission efficiency (ηsa) at 1.06 μm was ηsa = 0.63, being similar to the emission efficiencies of Nd:YAG laser active media anti-reflex coated. This fact demonstrates that 4.6 at.% Nd:LYSB constitutes an experimental and functional model of laser crystal with very efficient emission in the 1 μm spectral range, which allows obtaining efficient laser sources in the 1 μm range based on the 4.6 at.% Nd:LYSB crystal.

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3. ETAPA III. Ianuarie - Decembrie 2023

Dezvoltarea cristalelor Nd:LYSB cu eficienta de SFD ridicata in domeniul spectral verde (~ 0.5 μm).
Activitati specifice
III.1. Rafinarea compozitionala, cresterea cristalelor Nd:LYSB, caracterizarea proprietatilor NLO.
III.2. Caracterizarea spectroscopica de inalta rezolutie a cristalelor Nd:LYSB.
III.3. Experimente laser pe cristalele Nd:LYSB. Dezvoltarea de surse laser eficiente in domeniul spectral VIS .

Obiectivele specifice etapei III a proiectului BILAS au fost indeplinite integral.
● Rafinarea compozitionala, cresterea cristalelor Nd:LYSB, caracterizarea proprietatilor NLO.
Pe baza rezultatelor obtinute in cadrul etapelor anterioare ale proiectului, compozitiile nestoichiometrice La0.777Nd0.038Y0.435Sc2.75(BO3)4 si La0.790Nd0.025Y0.435Sc2.75(BO3)4 au fost selectate ca si compozitii initiale ale topiturii pentru cresterea prin metoda Czochralski a cristalelor de tip Nd:LYSB optimizate pentru obtinerea de emisie laser eficienta in domeniul spectral verde. Cristalele obtinute sunt transparente, nehigroscopice si stabile chimic, avand dimensiuni de aproximativ 10 - 12 mm in diametru si 25 - 30 mm in lungime. Concentratiile de ioni Nd3+ in cristalele crescute au fost determinate ca fiind 3.5 at.% (3.5 at.% Nd:LYSB) si respectiv 2.3 at.% (2.3 at.% Nd:LYSB). Proprietatile NLO ale cristalelor 3.5 at.% Nd:LYSB si 2.3 at.% Nd:LYSB au fost determinate si analizate. Rezultatele obtinute sunt similare cu cele obtinute pentru cristalul 4.6 at.% Nd:LYSB, in etapele anterioare ale proiectului.
● Caracterizarea spectroscopica de inalta rezolutie a cristalelor Nd:LYSB.
Proprietatile spectroscopice (absorbtie, emisie si cinetica emisiei) ale cristalelor 3.5 at.% Nd:LYSB si 2.3 at.% Nd:LYSB au fost determinate prin masuratori de spectroscopie optica de inalta rezolutie. Spectrele obtinute demonstreaza ca ionii Nd3+ dopati in cristale de tip LYSB ocupa doar pozitii de La3+ si nu prezinta o structura multicentrică. De asemenea, experimentele de cinetica emisiei au evidentiat faptul ca transferul de energie intre ionii Nd3+ este foarte mic, ca urmare a distantei mari dintre ionii Nd3+ din reteaua cristalina.

● Experimente laser pe cristalele Nd:LYSB. Dezvoltarea de surse laser eficiente in domeniul spectral VIS. Primele experimente de autodublare de frecventa (SFD) a emisiei laser din domeniul 1.06 μm au fost realizate pe o proba din cristalul 4.6 at.% Nd:LYSB taiata si orientata la unghi de acord de faza pentru SHG de tip I (θ= 35.3o, φ= 60o), neacoperita antireflex. Testele laser efectuate pe cristalele 2.3 at.% Nd:LYSB si 3.5 at.% Nd:LYSB au demonstrat ca acesta din urma constituie un model experimental si functional de sursa laser in verde bazata pe procese de SFD.

2. STAGE III. January - December 2023
Development of Nd:LYSB crystals with high SFD efficiency in the green spectral range (~ 0.5 μm).
Specific activities
III.1. Compositional refinement, growth of Nd:LYSB crystals, characterization of NLO properties.
III.2. High-resolution spectroscopic characterization of Nd:LYSB crystals.

III.3. Laser experiments on Nd:LYSB crystals. The development of efficient laser sources in the VIS spectral range.

The specific objectives of stage III of the BILAS project have been fully met.
● Compositional refinement, growth of Nd:LYSB crystals, characterization of NLO properties.
Based on the results obtained in the previous stages of the project, the non-stoichiometric compositions La0.777Nd0.038Y0.435Sc2.75(BO3)4 and La0.790Nd0.025Y0.435Sc2.75(BO3)4 were selected as the initial compositions of the melt for the growth by the Czochralski method of Nd:LYSB-type crystals optimized for obtaining efficient laser emission in the green spectral range. The obtained crystals are transparent, non-hygroscopic and chemically stable, having dimensions of approximately 10 - 12 mm in diameter and 25 - 30 mm in length. The concentrations of Nd3+ ions in the grown crystals were determined to be 3.5 at.% (3.5 at.% Nd:LYSB) and 2.3 at.% (2.3 at.% Nd:LYSB), respectively. The NLO properties of the 3.5 at.% Nd:LYSB and 2.3 at.% Nd:LYSB crystals were determined and analyzed. The obtained results are similar to those obtained for the 4.6 at.% Nd:LYSB crystal, in the previous stages of the project.
● High-resolution spectroscopic characterization of Nd:LYSB crystals.
The spectroscopic properties (absorption, emission, and emission kinetics) of the 3.5 at.% Nd:LYSB and 2.3 at.% Nd:LYSB crystals were determined by high-resolution optical spectroscopy measurements. The obtained spectra demonstrate that the Nd3+ ions doped in LYSB-type crystals occupy only the La3+ positions and do not present a multicentre structure. Also, the emission kinetics experiments revealed that the energy transfer between neighboring Nd3+ ions is very small, as a result of the large distance between the Nd3+ ions in the crystalline lattice.
● Laser experiments on Nd:LYSB crystals. The development of efficient laser sources in the VIS spectral range.
The first self-frequency doubling (SFD) experiments of laser emission in the 1.06 μm range were performed on a 4.6 at.% Nd:LYSB crystal sample cut and oriented at the phase-matching angle for type I SHG (θ= 35.3o , φ= 60o), without anti-reflective coatings. The laser tests performed on the 2.3 at.% Nd:LYSB and 3.5 at.% Nd:LYSB crystals demonstrated that the latter constitutes an experimental and functional model of a green laser source based on SFD processes.
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VALORIFICATION OF THE RESULTS

I. ARTICLES PUBLISHED IN ISI JOURNALS
1. C. A. Brandus, M. Greculeasa, A. Broasca, F. Voicu, L. Gheorghe, and N. Pavel, "Diode-pumped bifunctional Nd:LGSB laser passively Q-switched by a Cr4+:YAG saturable absorber," Opt. Mater. Express 11(3), 685-694 (2021). https://doi.org/10.1364/OME.416425
2. A. Broasca, M. Greculeasa, F. Voicu, G. Stanciu, S. Hau, C. Gheorghe, C. A. Brandus, N. Pavel, M. Enculescu, L. Gheorghe, “Growth and characterization of 3.5 at.% Nd:LGSB bifunctional crystal,” Opt. Mat. 123, 111832 (2022). https://doi.org/10.1016/j.optmat.2021.111832
3. S. Hau, G. Stanciu, D. Avram, C. Gheorghe, L. Gheorghe, “Energy transfer and luminescent properties of Tb3+ and (Tb3+, Yb3+) doped CNGG phosphors”, Journal of Rare Earths, 40(9), 1445-1453 (2022). IF 3.712, https://doi.org/10.1016/j.jre.2021.09.008
4. A. Broasca, M. Greculeasa, F. Voicu, G. Stanciu, S. Hau, C. Gheorghe, L. Gheorghe, “Pr:LGSB as a new nonlinear optical crystal: Czochralski growth and optical characterization,” J. Alloys & Comp. 908, 164633 (2022). https://doi.org/10.1016/j.jallcom.2022.164633
5. C. Gheorghe, S. Hau, L. Gheorghe, F. Voicu, M. Greculeasa, A. Broasca and G. Stanciu, “ RE3+-doped CNGG and CLNGG crystals (RE = Sm, Dy, and Pr): A review of current achievements,” Materials 16(1), 269 (2023). https://doi.org/10.3390/ma16010269
6. A. Broasca, M. Greculeasa, F. Voicu, C. Gheorghe and L Gheorghe, “Pure and Yb-Doped LaxYySc4-x-y(BO3)4 Crystals: A Review of Recent Advances,” Crystals 13(2), 169 (2023). https://doi.org/10.3390/cryst13020169
7. A. Broasca, M. Greculeasa, F. Voicu, S. Hau, C. Gheorghe, G. Croitoru, N. Pavel, G. Stanciu, A. Petris, P. Gheorghe, F. Albota, A. Serban, L. Gheorghe, “LGYSB:Nd - high-performance lasing in the near-infrared region,” J. Am. Chem. Soc. 146(3), 2196-2207 (2024). https://doi.org/10.1021/jacs.3c12371

II. Communications at International Conferences
1. M. Greculeasa, A. Broasca, F. Voicu, S. Hau, G. Croitoru, C. Brandus, G. Stanciu, C. Gheorghe, L. Gheorghe, “RE-doped LGSB (RE = Nd, Yb) as New High Performance Near-Infrared Laser Crystals,” 2021 Conference on Lasers and Electro-Optics/Europe - European Quantum Electronics Virtual Conferences (CLEO/Europe-EQEC 2021), 21-25 June 2021, presentation CA-P.7.
https://www.osapublishing.org/abstract.cfm?uri=CLEO_Europe-2021-ca_p_7
2. G. Stanciu, F. Voicu, C.-A. Brandus, E.-C. Tihon, S. Hau, C. Gheorghe, G. Croitoru, L. Gheorghe, “Development of a new sintering technique for fabricating high-quality Nd3+- and Yb3+-doped Y2O3 Transparent Ceramics,” 2021 Conference on Lasers and ElectroOptics/Europe - European Quantum Electronics Virtual Conferences (CLEO/Europe-EQEC 2021), 21-25 June 2021, presentation CE-P.4.
https://www.osapublishing.org/abstract.cfm?uri=CLEO_Europe-2021-ce_p_4
3. A. Broasca, M. Greculeasa, F. Voicu, G. Stanciu, S. Hau, C. Gheorghe, G. Croitoru, N. Pavel, L. Gheorghe, “LYSB and Yb-Doped LYSB crystals: Czochralski growth, optical characterization and laser emission performances,” OSA Laser Congress Virtual Event, 03 Oct. - 07 Oct. 2021; presentation ATh1A.6. https://www.osapublishing.org/abstract.cfm?uri=ASSL-2021-ATh1A.6
4. S. Hau, M. Greculeasa, A. Broasca, F. Voicu, G. Stanciu, D. Avram, M. Enculescu, L. Gheorghe, C. Gheorghe, ”Pr3+-doped Ca3(Ta, Ga)5O12 single crystal as potential laser material in the visible range,” 7th European Conference on Crystal Growth - ECCG7, 25-27 July 2022, Paris, France; presentation P20.
5. L. Gheorghe, A. Broasca, M. Greculeasa, F. Voicu, G. Stanciu, S. Hau, C. Gheorghe, ”Czochralski growth and characterization of newly developed Pr:LGSB nonlinear optical and laser crystal,” 7th European Conference on Crystal Growth - ECCG7, 25-27 July 2022, Paris, France.
6. A. Broasca, M. Greculeasa, F. Voicu, G. Stanciu, S. Hau, C. Gheorghe, and L. Gheorghe, ”Growth and optical properties of the newly developed Pr:LGSB bifunctional crystal,” 10th EPS-QEOD EUROPHOTON Conference, 28 Aug. - 2 Sep. 2022, Hannover, Germany; presentation TUE-P-1.8.7. M. Greculeasa, A. Broasca, F. Voicu, G. Stanciu, S. Hau, C. Gheorghe, C.A. Brandus, N. Pavel, and L. Gheorghe, ”Development of Czochralski-grown La0.733Nd0.035Gd0.452Sc2.75(BO3)4 as a new bifunctional laser and nonlinear crystal,” 10th EPS-QEOD EUROPHOTON Conference, 28 Aug. - 2 Sep. 2022, Hannover, Germany; presentation TUE-P-1.9.
7. M. Greculeasa, A. Broasca, F. Voicu, G. Stanciu, S. Hau, C. Gheorghe, C.A. Brandus, N. Pavel, and L. Gheorghe, “Development of Czochralski-grown La0.733Nd0.035Gd0.452Sc2.75(BO3)4 as a new bifunctional laser and nonlinear crystal,” 10th EPS-QEOD EUROPHOTON Conference, 28 Aug. - 2 Sep. 2022, Hannover, Germany; presentation TUE-P-1.9.
8. C.-A. Brandus and L. Gheorghe, “Exploring χ(2) nonlinearity for mode-locking of Nd:LGSB laser,” International Conference on Laser, Plasma and Radiation - Science and Technology, June 7-10, 2022 Bucharest, Romania; presentation P2-07.
9. M. Greculeasa, A. Broasca, F. Voicu, G. Stanciu, S. Hau, C. Gheorghe, C.A. Brandus, N. Pavel, M. Enculescu, L. Gheorghe, “Crystal Growth and Characterization of La0.733Nd0.035Gd0.452Sc2.78(BO3)4 as a New Bifunctional Laser and Nonlinear Optical Crystal,” International Conference on Laser, Plasma and Radiation - Science and Technology, June 7-10, 2022 Bucharest, Romania; presentation P2-05 (poster presentation).
10. A. Broasca, M. Greculeasa, F. Voicu, G. Stanciu, S. Hau, C. Gheorghe, L. Gheorghe, “Czochralski Growth and Characterization of new Pr:LGSB Nonlinear Optical Crystal,” International Conference on Laser, Plasma and Radiation - Science and Technology, June 7-10, 2022 Bucharest, Romania; presentation P2-04.
11. S. Hau, C. Gheorghe, L. Gheorghe, F. Voicu, M. Greculeasa, A. Brosca, G. Stanciu, D. Avram, M. Enculescu, “Luminescence and optical thermometry of the Pr3+ ions doped Ca3(M,Ga)5O12 (M5+= Nb, Ta) garnet phosphors,” International Conference on Laser, Plasma and Radiation -Science and Technology, June 7-10, 2022 Bucharest, Romania; presentation P2-01.
12. L. M. Gheorghe, A. Broasca, M. Greculeasa, F. Voicu, G. Croitoru, S. Hau, C. Gheorghe, N. Pavel, “Yb- and Nd-doped LaxGdySc4-x-y(BO3)4 (LGSB) as new high performance near-infrared laser crystals," The 9th Tiny Integrated Laser and Laser Ignition Conference 2022, 19-21 April 2023, Pacifico Yokohama, Yokohama, Japan, presentation TILA-LICp-01.
13. G. Stanciu, F. Voicu, C. A. Brandus, C. E. Tihon, S. Hau, C. Gheorghe, G. Croitoru, L. M. Gheorghe, N. Pavel, “RE3+:Y2O3 transparent ceramic media realized via a multi-step sintering method," The 9th Tiny Integrated Laser and Laser Ignition Conference 2022, 19-21 April 2023, Pacifico Yokohama, Yokohama, Japan, presentation TILA-LICp-02.
14. L. Gheorghe, A. Broasca, M. Greculeasa, F. Voicu, C. Gheorghe, S. Hau, G. Stanciu, C. A. Brandus, N. Pavel, ” Czochralski-grown LGSB crystals as high-performance NIR laser crystals and SFD crystals in the VIS spectral range,” International Conference on Crystal Growth and Epitaxy - ICCGE-20, 30 July - 04 August 2023, Naples, Italy; (poster presentation PS 1 - P49).
15. C. Gheorghe, S. Hau, A. Broasca, M. Greculeasa, F. Voicu, M. Enculescu, L. Gheorghe, ”Ca3(Ta,Ga)5O12:Pr3+ as potential laser crystal emitting in the blue and red spectral domains,” International Conference on Crystal Growth and Epitaxy - ICCGE-20, 30 July - 04 August 2023, Naples, Italy; (poster presentation PS 3 - P15).
16. A. Broasca, M. Greculeasa, F. Voicu, S. Hau, G. Stanciu, C. Gheorghe, G. Croitoru, N. Pavel, L. Gheorghe, ”Growth and optical properties of Nd:LYSB as a new laser and nonlinear optical borate crystal,” International Conference on Crystal Growth and Epitaxy - ICCGE-20, 30 July - 04 August 2023, Naples, Italy; (oral presentation Optical Crystals 4 - O3).
17. M. Greculeasa, A. Broasca, F. Voicu, G. Stanciu, S. Hau, C. Gheorghe, G. Croitoru, N. Pavel, L. Gheorghe, ”Development of LYSB and Yb-doped LYSB crystals as new candidates for the next generation of nonlinear optical and/or laser crystals,” International Conference on Crystal Growth and Epitaxy - ICCGE-20, 30 July - 04 August 2023, Naples, Italy; (oral presentation Optical Crystals 6 - O4).


III. PARTICIPATION AT INTERNATIONAL SUMMER SCHOOLS
● Participation of two members of the project team (Alin Broasca and Madalin Greculeasa) at the “Siegman International School on Lasers,” 19 - 23 July 2021, OSA Virtual Event.
● Alin Broasca and Madalin Greculeasa: Participation in 18th International Summer School on Crystal Growth, 23 - 29 July  2023, Parma, Italy.

IV. SUBMITTED PATENT APPLICATIONS
● Gheorghe Lucian-Marian, Broasca Alin-Constantin, Greculeasa Madalin, Voicu Flavius-Marian, Chircus Gheorghe-Laurentiu, “Metoda de creştere prin tehnica Czochralski a monocristalului cu topire incongruentă LaxYyNdzSc4-x-y-z(BO3)4 (Nd:LYSB),” cerere de Brevet de Inventie depusa la OSIM cu nr. de inregistrare A/00730 din data de 15 noiembrie 2022.
● Gheorghe Lucian-Marian, Broască Alin-Constantin, Greculeasa Mădălin, Voicu Flavius-Marian, Gheorghe Cristina-Petruţa, Hău Ștefania, Croitoru Gabriela, Stanciu George, “Cristal laser de tip borat cu emisie eficientă in domeniul infraroșu apropiat,” cerere de Brevet de Inventie depusa la OSIM cu nr. de inregistrare A/00743 din data de 24 noiembrie 2023.

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Laboratory of Solid-State Quantum Electronics