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1. Chaotic dynamics in passively Q-switched Tm:LiYF4 laser operating at 2.3 μm on the 3H4 → 3H5 transition

Author

Hippolyte Dupont, Matthieu Glasset, Pavel Loiko, Patrick Georges, and Frédéric Druon

Subjects
Applied optics. Photonics, TA1501-1820
Abstract

We report on the chaotic dynamics in a passively Q-switched 2.3-μm thulium laser operating on the 3H4 → 3H5 transition. The experiment exploits a Tm:LiYF4 crystal and various laser cavity configurations, involving an optional cascade laser on the 3F4 → 3H6 transition at 1.9 μm. The saturable absorber employed is Cr2+:ZnSe, which is exclusively saturated by the 2.3 μm laser. An analysis of the Q-switched dynamics shows a pronounced inclination of the laser operation toward the unstable and chaotic behavior. To understand the origins of this chaos, we monitor the population of the metastable 3F4 level via cascade laser operation at 1.9 μm, underlying this variable as an interesting parameter to survey chaotic instabilities.

Published
2024
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2. Growth of ultimate high-density scintillating films for high-resolution X-ray imaging at synchrotrons

Author

Laura Wollesen, Paul-Antoine Douissard, Philip Cook, Pavel Loiko, Gurvan Brasse, Jérémie Margueritat, Patrice Camy, Thierry Martin, and Christophe Dujardin

Subjects
Liquid phase epitaxy, Thin films, Scintillation, High-density compounds, Applied optics. Photonics, TA1501-1820, Optics. Light, QC350-467
Abstract

Scintillators are X-ray to visible light converters applied in X-ray imaging detectors used at synchrotrons. Drastically improved performances of the 4th generation synchrotron sources enable us to perform X-ray imaging experiments at higher energies. For high spatial resolution X-ray imaging (micrometer to submicrometer), thin scintillating films are required. Consequently, especially for high X-ray energies (30keV to 100keV), the detection efficiency is limited due to the low X-ray absorption efficiency of the thin films. We have used Liquid Phase Epitaxy (LPE) to grow thin films of one of the ultimate high-density materials, Lu2Hf2O7:Eu3+, which demonstrate scintillating properties and thus combine high spatial resolution and maximized absorption efficiency. X-ray imaging experiments demonstrate that the Modulation Transfer Function (MTF) reaches 10% at 900 lp/mm, and radiographs visually confirm the promising imaging properties. We present structural, luminescent, and scintillation characterization of Lu2Hf2O7:Eu thin films grown on ZrO2:Y substrates, showing that the films crystallize in the disordered fluorite structure and the europium ions incorporate into the structure and enhance the luminescence intensity. This contribution is a first step toward developing promising ultra-dense, hafnate-based scintillating screens for high spatial resolution X-ray imaging.

Published
2024
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3. Kerr-Lens Mode-Locked Yb:BaF2 Laser

Author

Zhi-Qiang Li, Zhang-Lang Lin, Pavel Loiko, Huang-Jun Zeng, Ge Zhang, Hai-Yu Nie, Simone Normani, Abdelmjid Benayad, Patrice Camy, Xavier Mateos, Valentin Petrov, and Weidong Chen

Subjects
ultrafast laser, solid-state laser, Ytterbium laser, mode locking, Applied optics. Photonics, TA1501-1820
Abstract

We present sub-50 fs soliton pulse generation from a diode-pumped Kerr-lens mode-locked laser based on an Yb3+-doped BaF2 crystal. Utilizing a spatially single-mode, fiber-coupled InGaAs laser diode at 976 nm as a pump source, the Yb:BaF2 laser generates pulses as short as 46 fs at 1060.1 nm with an average output power of 45 mW at a pulse repetition rate of ~65.6 MHz via soft-aperture Kerr-lens mode locking. To the best of our knowledge, this represents the first demonstration of Kerr-lens mode-locked operation of the Yb:BaF2 crystal, as well as the shortest pulse duration ever achieved from any diode-pumped mode-locked laser based on an Yb3+-doped alkaline-earth fluoride crystal.

Published
2024
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4. Continuous-Wave and Mode-Locked Operation of an In-Band Pumped Tm,Ho,Lu:CaGdAlO4 Laser

Author

Huangjun Zeng, Wenze Xue, Robert T. Murray, Weidong Chen, Zhongben Pan, Li Wang, Chen Cui, Pavel Loiko, Xavier Mateos, Uwe Griebner, and Valentin Petrov

Subjects
mode-locking, Ho laser, CaGdAlO4, inhomogeneous broadening, disordered crystal, mixed crystal, Technology, Engineering (General). Civil engineering (General), TA1-2040, Biology (General), QH301-705.5, Physics, QC1-999, Chemistry, QD1-999
Abstract

We investigate in-band pumping of a Tm,Ho,Lu:CaGdAlO4 laser using a Raman-shifted Er-fiber laser (1678 nm), in the continuous-wave (CW) and mode-locked (ML) regimes. A maximum output power of 524 mW is obtained in the CW regime with a 5% output coupler at an absorbed pump power of 2.04 W, corresponding to a slope efficiency of 27.9%. A maximum CW wavelength tuning range of 160 nm at the zero level, from 1984 to 2144 nm, is obtained with a 0.2% output coupler. In the ML regime, pumping with 5.5 W (unpolarized), the average output power (0.2% output coupler) reaches 148 mW at a repetition rate of ~96 MHz. The output spectrum is centered at 2071.5 nm with a FWHM of 21.5 nm (σ-polarization). The pulse duration amounts to 218 fs (time-bandwidth product equal to 0.327).

Published
2023
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5. Growth, Structure, Spectroscopy, and Laser Operation of a 'Mixed' Yb:(Y,Lu)3Al5O12 Garnet Crystal

Author

Sami Slimi, Pavel Loiko, Mingyan Pan, Pauline Lehoux, Venkatesan Jambunathan, Martin Smrz, Tomas Mocek, Yicheng Wang, Weidong Chen, Valentin Petrov, Rosa Maria Solé, Magdalena Aguiló, Francesc Díaz, Patrice Camy, and Xavier Mateos

Subjects
garnet crystals, ytterbium ion, crystal structure, optical spectroscopy, solid-state lasers, Crystallography, QD901-999
Abstract

A single crystal of ytterbium-doped “mixed” yttrium–lutetium aluminum garnet with a stoichiometric composition of (Y0.601Lu0.233Yb0.166)3Al5O12 was grown by the Czochralski method and its structure, vibronic, spectroscopic, and laser properties were studied. The stimulated-emission cross-section for Yb3+ ions was maximized to 2.53 × 10−20 cm2 at 1031 nm. The emission bandwidth was ~8 nm, and the reabsorption-free luminescence lifetime of the 2F5/2 state was 1.063 ms. Pumped at 941 nm, the Yb laser generated a maximum output power of 1.04 W at 1.03 and 1.05 μm with a high slope efficiency of 76.4% and a laser threshold of 76 mW. A continuous wavelength tuning over a range of 51.6 nm (1026.4–1078.0 nm) was also achieved. Power scaling was achieved using a 969 nm diode-pumped microchip cavity. A maximum output power of ~9 W was obtained at 1.05 μm with a slope efficiency of 76% and an almost circular laser beam profile.

Published
2023
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6. Oriented zinc oxide nanorods: A novel saturable absorber for lasers in the near-infrared

Author

Pavel Loiko, Tanujjal Bora, Josep Maria Serres, Haohai Yu, Magdalena Aguiló, Francesc Díaz, Uwe Griebner, Valentin Petrov, Xavier Mateos, and Joydeep Dutta

Subjects
oriented nanorods, Q-switching, saturable absorption, solid-state lasers, zinc oxide, Technology, Chemical technology, TP1-1185, Science, Physics, QC1-999
Abstract

Zinc oxide (ZnO) nanorods (NRs) oriented along the crystallographic [001] axis are grown by the hydrothermal method on glass substrates. The ZnO NRs exhibit a broadband (1–2 µm) near-IR absorption ascribed to the singly charged zinc vacancy VZn−1. The saturable absorption of the ZnO NRs is studied at ≈1 µm under picosecond excitation, revealing a low saturation intensity, ≈10 kW/cm2, and high fraction of the saturable losses. The ZnO NRs are applied as saturable absorbers in diode-pumped Yb (≈1.03 µm) and Tm (≈1.94 µm) lasers generating nanosecond pulses. The ZnO NRs grown on various optical surfaces are promising broadband saturable absorbers for nanosecond near-IR lasers in bulk and waveguide geometries.

Published
2018
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7. SESAM Mode-Locked Yb:Ca3Gd2(BO3)4 Femtosecond Laser

Author

Huang-Jun Zeng, Zhang-Lang Lin, Wen-Ze Xue, Ge Zhang, Zhongben Pan, Haifeng Lin, Pavel Loiko, Xavier Mateos, Valentin Petrov, Li Wang, and Weidong Chen

Subjects
ultrafast laser, solid-state laser, ytterbium laser, mode-locking, Technology, Engineering (General). Civil engineering (General), TA1-2040, Biology (General), QH301-705.5, Physics, QC1-999, Chemistry, QD1-999
Abstract

We report on the first passively mode-locked femtosecond-laser operation of a disordered Yb:Ca3Gd2(BO3)4 crystal using a SEmiconductor Saturable Absorber Mirror (SESAM). Pumping with a single-transverse mode fiber-coupled laser diode at 976 nm, nearly Fourier-transform-limited pulses as short as 96 fs are generated at 1045 nm with an average output power of 205 mW and a pulse repetition rate of ~67.3 MHz. In the continuous-wave regime, high slope efficiency up to 59.2% and low laser thresholds down to 25 mW are obtained. Continuous wavelength tuning between 1006–1074 nm (a tuning range of 68 nm) is demonstrated. Yb:Ca3Gd2(BO3)4 crystals are promising for the development of ultrafast lasers at ~1 μm.

Published
2021
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8. Thermal Lensing and Multiwatt Microchip Laser Operation of Yb:YCOB Crystals

Author

Pavel Loiko, Josep Maria Serres, Xavier Mateos, Haohai Yu, Huaijin Zhang, Junhai Liu, Konstantin Yumashev, Uwe Griebner, Valentin Petrov, Magdalena Aguilo, and Francesc Diaz

Subjects
Diode-pumped lasers, microchip, thermal lensing, oxoborates, Applied optics. Photonics, TA1501-1820, Optics. Light, QC350-467
Abstract

Thermal lensing is studied in monoclinic Yb:Ca4YO(BO3)3 (Yb: YCOB) oxoborate crystals cut along the optical indicatrix axes. For all orientations, the thermal lens is positive. In the Z-cut crystal, the sensitivity factors of the thermal lens are MZ-X = 2.4 and MZ-Y = 2.8 m-1/W (for E∥X), and the astigmatism degree is as low as S/M = 14%. The positive thermal lens in Yb:YCOB is related to the large thermal expansion and strong photoelastic effect. Microchip lasers are realized with 3-mm-long X, Y, and Z-cut 15 at.% Yb:YCOB crystals. With a Z-cut crystal, maximum output power of 8.35 W is achieved at ~1040 nm with slope efficiency of 70%. Using various crystal cuts and output coupler transmissions, multiwatt emission in the spectral range of 1033-1091 nm is demonstrated.

Published
2016
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9. Raman Laser Spectrometer: Application to 12C/13C Isotope Identification in CH4 and CO2 Greenhouse Gases

Author

Vladimir Vitkin, Anton Polishchuk, Ian Chubchenko, Evgeniy Popov, Konstantin Grigorenko, Artem Kharitonov, Arsen Davtian, Anton Kovalev, Valeria Kurikova, Patrice Camy, Pavel Loiko, Magdalena Aguiló, Francesc Díaz, and Xavier Mateos

Subjects
Raman laser spectrometer, carbon isotopes, greenhouse gases, carbon dioxide, methane, human exhalation, Technology, Engineering (General). Civil engineering (General), TA1-2040, Biology (General), QH301-705.5, Physics, QC1-999, Chemistry, QD1-999
Abstract

A compact Raman laser gas spectrometer is developed. It comprises a high-power green laser at 532.123 nm as an excitation source and a specially designed gas cell with an internal volume of less than 0.6 cm3 that can withstand gas pressures up to 100 atm. The resolution of the spectrometer is ~1 cm−1. The Raman spectra of chemically pure isotopically enriched carbon dioxide (12CO2, 13CO2) and methane (12CH4, 13CH4) gases are studied. The expected limit of detection (LOD) is less than 100 ppm for the isotopologues of CO2 and less than 25 ppm for those of CH4 (at a gas pressure of 50 atm.), making the developed spectrometer promising for studying the sources of emissions of greenhouse gases by resolving their isotopologue composition. We also show the suitability of the spectrometer for Raman spectroscopy of human exhalation.

Published
2020
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10. Graphene Q-Switched Compact Yb:YAG Laser

Author

Josep Maria Serres, Venkatesan Jambunathan, Xavier Mateos, Pavel Loiko, Antonio Lucianetti, Tomas Mocek, Konstantin Yumashev, Valentin Petrov, Uwe Griebner, Magdalena Aguilo, and Francesc Diaz

Subjects
Graphene, saturable absorber, Q-switched laser, Applied optics. Photonics, TA1501-1820, Optics. Light, QC350-467
Abstract

We describe a compact Yb:YAG laser Q-switched by a graphene-based saturable absorber and pumped by a laser diode at 932 or 969 nm. The compact laser generates a maximum average output power value of 185 mW at 1032 nm with a slope efficiency value of 12%. The shortest duration of the Q-switched pulse achieved is 228 ns at a repetition frequency of 285 kHz. The maximum pulse energy amounts to 0.65 μJ.

Published
2015
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12. ZnO – Yb2O3 composite optical ceramics: Synthesis, structure and spectral-luminescent properties

Author

I. D. Venevtsev, Mikhail A. Baranov, K. Kundzins, E. I. Gorokhova, Aleksander A. Zhilin, Olga Dymshits, Pavel Loiko, Liza Basyrova, Alexander Khubetsov, Irina Alekseeva, Faina Muktepavela, S. B. Eron’ko, M. Tsenter, Eugenia Oreschenko, S.I. Vavilov State Optical Institute, Peter the Great St. Petersburg Polytechnic University (SPbPU), Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), ITMO University [Russia], D.V. Efremov Institute of Electrophysical Apparatus, University of Latvia (LU), Optique, Matériaux et Laser (OML), and Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN)

Subjects
Ytterbium, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Materials science, Infrared, Analytical chemistry, zinc oxide, chemistry.chemical_element, ytterbium sesquioxide, Hot pressing, Sesquioxide, Grain growth, chemistry, visual_art, Materials Chemistry, Ceramics and Composites, visual_art.visual_art_medium, Grain boundary, structure, Ceramic, luminescence, Luminescence, optical ceramics
Abstract

International audience; Zinc oxide optical ceramics containing 0 – 2 wt% ytterbium are prepared byuniaxial hot pressing of commercial oxides at 1150 and 1180 °C. The ceramics have themain crystalline phase of hexagonal wurtzite-type ZnO. Ytterbium ions do not enter theZnO crystals but form a cubic sesquioxide phase of Yb2O3 located at the ZnO grainboundaries. Yb acts as an inhibitor for the ZnO grain growth. The ceramics exhibittransmittance up to 60% in the visible. Their transmission in the infrared is determinedby the free charge carrier absorption. The Yb3+ ions are found in C2 and C3i sites in Yb2O3crystals. Under X-ray excitation, the ceramics exhibit intense luminescence bands in theblue (near-band-edge emission) and green (defect emission) whose positions, intensitiesand decay times depend on the Yb content. Yb2O3 causes a redistribution of luminescenceintensity in favor of the near-band-edge emission and fastens the emission decay.

Published
2022
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13. Cryogenic laser operation of a 'mixed' Yb:LuYAG garnet crystal

Author

Sami Slimi, Venkatesan Jambunathan, Mingyan Pan, Yicheng Wang, Weidong Chen, Pavel Loiko, Rosa Maria Solé, Magdalena Aguiló, Francesc Díaz, Martin Smrz, Tomas Mocek, and Xavier Mateos

Subjects
Physics and Astronomy (miscellaneous), General Engineering, General Physics and Astronomy
Abstract

We report on the continuous-wave and passively Q-switched operation of a compositionally “mixed” heavily doped 16.6 at.% Yb:(Y,Lu)3Al5O12 garnet crystal at cryogenic temperatures (100–200 K), pumped by a volume Bragg grating stabilized diode laser emitting at 969 nm. At 140 K, in the continuous-wave regime, a maximum output power of 10.65 W was achieved at ~ 1029 nm with a slope efficiency of 56% (versus the incident pump power), a laser threshold of 1.05 W and excellent beam quality. Using Cr4+:YAG as a saturable absorber, the passively Q-switched laser generated pulses with an energy/duration of 0.15 mJ/201 ns, respectively, at a repetition rate of 39.7 kHz, corresponding to a peak power of 0.39 kW.

Published
2023
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16. Dual-wavelength-pumping of mid-infrared Tm:YLF laser at 2.3 µm: demonstration of pump seeding and recycling processes

Author

Hippolyte Dupont, Lauren Guillemot, Pavel Loiko, Alain Braud, Jean-Louis Doualan, Patrice Camy, Patrick Georges, Frédéric Druon, Laboratoire Charles Fabry / Lasers, Laboratoire Charles Fabry (LCF), Institut d'Optique Graduate School (IOGS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), and Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Atomic and Molecular Physics, and Optics
Abstract

Upconversion pumping of thulium lasers emitting around 2.3 µm (the 3H4 → 3H5 transition) has recently attracted a lot of attention as it is compatible with the mature Yb-laser technology. To explore this possibility, we built a mid-infrared Tm:LiYF4 laser pumped by an Yb:CaF2 laser at 1.05 µm delivering an output power of 110 mW at 2.31 µm for a maximum incident pump power of 2.0 W. A strong absorption issue appeared in the Tm laser: the slope efficiency vs. the incident pump power was 7.6% while that vs. the absorbed pump power reached 29%. To overcome this issue, a dual-wavelength pumping at 0.78 µm and 1.05 µm was explored (combining both the direct and upconversion pumping schemes). The reciprocal interplay between the two pumps was studied to evaluate their benefits in terms of the pump absorption and laser efficiency. We observed an interesting decrease of the laser threshold for upconversion pumping when adding a small fraction of the direct pump revealing a seeding effect for the excited-state absorption from the metastable 3F4 level. A recycling process of this manifold by excited-state absorption in the 3F4 → 3F2,3 loop was also observed. The pump absorption seeding is a viable route for the development of low-threshold upconversion pumped thulium lasers.

Published
2022
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17. Kerr-lens mode-locked Yb:YAlO

Author

Weidong, Chen, Zhang-Lang, Lin, Wen-Ze, Xue, Huang-Jun, Zeng, Ge, Zhang, Pavel, Loiko, Yongguang, Zhao, Xiaodong, Xu, Jun, Xu, Xavier, Mateos, Haifeng, Lin, Li, Wang, and Valentin, Petrov

Abstract

We report on a Kerr-lens mode-locked Yb:YAlO

Published
2022

18. Deep-red laser operation of cleaved single-crystal plates of Eu:CsGd(MoO4)2 molybdate

Author

Amandine Baillard, Pavel Loiko, Anatoly Pavlyuk, Gurvan Brasse, Alain Braud, and Patrice Camy

Subjects
Atomic and Molecular Physics, and Optics
Abstract

We report on the first deep-red laser operation of a heavily Eu3+-doped cesium gadolinium double molybdate crystal with a perfect cleavage. A 17 at. % Eu:CsGd(MoO4)2 laser based on cleaved single-crystal plates generated a maximum continuous-wave output power of 212 mW at 703.1 nm (5D0 → 7F4 transition) with a slope efficiency of 30.1%, a low laser threshold of 51 mW, linear polarization, and a beam quality factor M2 = 1.6–1.7. This monoclinic crystal is promising for deep-red microchip lasers.

Published
2023
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19. Tm:CALGO lasers at 2.32 µm: cascade lasing and upconversion pumping

Author

Hippolyte Dupont, Pavel Loiko, Aleksey Tyazhev, Luidgi Giordano, Zhongben Pan, Hongwei Chu, Dechun Li, Bruno Viana, Ammar Hideur, Lauren Guillemot, Alain Braud, Patrice Camy, Patrick Georges, and Frédéric Druon

Subjects
Atomic and Molecular Physics, and Optics
Abstract

We report on the first laser operation of a disordered Tm:CaGdAlO4 crystal on the 3H4 → 3H5 transition. Under direct pumping at 0.79 µm, it generates 264 mW at 2.32 µm with a slope efficiency of 13.9% and 22.5% vs. incident and absorbed pump power, respectively, and a linear polarization (σ). Two strategies to overcome the bottleneck effect of the metastable 3F4 Tm3+ state leading to the ground-state bleaching are exploited: cascade lasing on the 3H4 → 3H5 and 3F4 → 3H6 transitions and dual-wavelength pumping at 0.79 and 1.05 µm combining the direct and upconversion pumping schemes. The cascade Tm-laser generates a maximum output power of 585 mW at 1.77 µm (3F4 → 3H6) and 2.32 µm (3H4 → 3H5) with a higher slope efficiency of 28.3% and a lower laser threshold of 1.43 W, out of which 332 mW are achieved at 2.32 µm. Under dual-wavelength pumping, further power scaling to 357 mW at at 2.32 µm is observed at the expense of increased laser threshold. To support the upconversion pumping experiment, excited-state absorption spectra of Tm3+ ions for the 3F4 → 3F2,3 and 3F4 → 3H4 transitions are measured for polarized light. Tm3+ ions in CaGdAlO4 exhibit broadband emission at 2.3 - 2.5 µm making this crystal promising for ultrashort pulse generation.

Published
2023
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20. Spectroscopy and 2.8 µm laser operation of disordered Er:CLNGG crystals

Author

Simone Normani, Pavel Loiko, Zhongben Pan, Elena Dunina, Liudmila Fomicheva, Alexey Kornienko, Alain Braud, Weidong Chen, Uwe Griebner, Valentin Petrov, and Patrice Camy

Subjects
Atomic and Molecular Physics, and Optics
Abstract

We report on the first, to the best of our knowledge, laser operation on the 4I11/2 → 4I13/2 transition of erbium-doped disordered calcium lithium niobium gallium garnet (CLNGG) crystals with broadband mid-infrared emission properties. A 41.4 at.% Er:CLNGG continuous-wave laser generated 292 mW at 2.80 µm with 23.3% slope efficiency and a laser threshold of 209 mW. Er3+ ions in CLNGG feature inhomogeneously broadened spectral bands (σSE = 1.79 × 10−21 cm2 at 2.79 µm; emission bandwidth, 27.5 nm), a large luminescence branching ratio for the 4I11/2 → 4I13/2 transition of 17.9%, and a favorable ratio of the 4I11/2 and 4I13/2 lifetimes, exhibiting values of 0.34 ms and 1.17 ms (for 41.4 at.% Er3+), respectively.

Published
2023
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21. Sub-50 fs diode-pumped SESAM mode-locked Yb:SrF2 laser

Author

Wen-Ze Xue, Pavel Loiko, Zhang-Lang Lin, Huang-Jun Zeng, Ge Zhang, Abdelmjid Benayad, Simone Normani, Patrice Camy, Xavier Mateos, Valentin Petrov, Li Wang, and Weidong Chen

Subjects
Atomic and Molecular Physics, and Optics
Abstract

We report on sub-50 fs pulse generation from a passively mode-locked Yb:SrF2 laser pumped with a spatially single-mode, fiber-coupled laser diode at 976 nm. In the continuous-wave regime, the Yb:SrF2 laser generated a maximum output power of 704 mW at 1048 nm with a threshold of 64 mW and a slope efficiency of 77.2%. A continuous wavelength tuning across 89 nm (1006 – 1095 nm) was achieved with a Lyot filter. By implementing a SEmiconductor Saturable Absorber Mirror (SESAM) for initiating and sustaining the mode-locked operation, soliton pulses as short as 49 fs were generated at 1057 nm with an average output power of 117 mW at a pulse repetition rate of ∼75.9 MHz. The maximum average output power of the mode-locked Yb:SrF2 laser was scaled up to 313 mW for slightly longer pulses of 70 fs at 1049.4 nm, corresponding to a peak power of 51.9 kW and an optical efficiency of 34.7%.

Published
2023
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22. Tm,Ho:Ca(Gd,Lu)AlO4 crystals: Polarized spectroscopy and laser operation

Author

Zhongben Pan, Pavel Loiko, Josep Maria Serres, Hualei Yuan, Yicheng Wang, Li Wang, Yongguang Zhao, Rosa Maria Solé, Magdalena Aguiló, Francesc Díaz, Patrice Camy, Weidong Chen, Uwe Griebner, Valentin Petrov, and Xavier Mateos

Subjects
Biophysics, General Chemistry, Condensed Matter Physics, Biochemistry, Atomic and Molecular Physics, and Optics
Published
2023
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23. Stimulated-emission cross-sections of trivalent erbium ions in the cubic sesquioxides Y2O3, Lu2O3, and Sc2O3

Author

Anastasia Uvarova, Pavel Loiko, Sascha Kalusniak, Elena Dunina, Liudmila Fomicheva, Alexey Kornienko, Stanislav Balabanov, Alain Braud, Patrice Camy, and Christian Kränkel

Subjects
Electronic, Optical and Magnetic Materials
Abstract

We report on a detailed revision of the spectroscopic properties of Er3+ ions in the cubic sesquioxide host crystals R2O3 (R = Y, Lu and Sc). The 4f-4f transition probabilities are calculated by applying a modified Judd-Ofelt theory accounting for configuration interaction based on the measured absorption spectra. The stimulated-emission cross-sections for the 4I11/2 → 4I13/2 (at ∼2.8 µm) and 4I13/2 → 4I15/2 (at ∼1.6 µm) transitions of Er3+ ions are determined and the luminescence dynamics from the 4I11/2 and 4I13/2 manifolds are studied at different temperatures. It is found that the luminescence lifetime of the 4I11/2 state strongly depends on the host-forming R3+ cation even at low temperatures due to a non-negligible non-radiative multiphonon decay channel. Er:Y2O3 exhibits the lowest phonon energies and consequently the longest 4I11/2 luminescence lifetimes. A disagreement between the absorption and emission probabilities for the 4I15/2 ↔ 4I11/2 transition of Er3+ ions is observed at room temperature and explained considering the distribution of Er3+ ions over two non-equivalent crystallographic sites, C2 and C3i.

Published
2023
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24. Excited-state absorption and upconversion pumping of Tm3+-doped potassium lutetium double tungstate

Author

Aleksey Tyazhev, Pavel Loiko, Lauren Guillemot, Alexandre Kouta, Rosa Maria Solé, Xavier Mateos, Magdalena Aguiló, Francesc Díaz, Hippolyte Dupont, Patrick Georges, Frédéric Druon, Alain Braud, Patrice Camy, and Ammar Hideur

Subjects
Atomic and Molecular Physics, and Optics
Abstract

We report on a bulk thulium laser operating on the 3H4 → 3H5 transition with pure upconversion pumping at 1064 nm by an ytterbium fiber laser (addressing the 3F4 → 3F2,3 excited-state absorption (ESA) transition of Tm3+ ions) generating 433 mW at 2291 nm with a slope efficiency of 7.4% / 33.2% vs. the incident / absorbed pump power, respectively, and linear laser polarization representing the highest output power ever extracted from any bulk 2.3 µm thulium laser with upconversion pumping. As a gain material, a Tm3+-doped potassium lutetium double tungstate crystal is employed. The polarized ESA spectra of this material in the near-infrared are measured by the pump-probe method. The possible benefits of dual-wavelength pumping at 0.79 and 1.06 µm are also explored, indicating a positive effect of co-pumping at 0.79 µm on reducing the threshold pump power for upconversion pumping.

Published
2023
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25. Cascade lasing at ∼2 μm and ∼2.3 μm in a diode-pumped Tm:YVO4 laser

Author

Xiaoxu Yu, Zhognben Pan, Hongwei Chu, Fangyuan Zha, Han Pan, Lijuan Ma, Pavel Loiko, Patrice Camy, and Dechun Li

Subjects
Atomic and Molecular Physics, and Optics
Abstract

We report on the cascade continuous-wave operation of a diode-pumped Tm:YVO4 laser on the 3F4 → 3H6 (at ∼2 μm) and 3H4 → 3H5 (at ∼2.3 μm) Tm3+ transitions. Pumped with a fiber-coupled spatially multimode 794 nm AlGaAs laser diode, the 1.5 at.% Tm:YVO4 laser yielded a maximum total output power of 6.09 W with a slope efficiency of 35.7% out of which the 3H4 → 3H5 laser emission corresponded to 1.15 W at 2291-2295 and 2362-2371 nm with a slope efficiency of 7.9% and a laser threshold of 6.25 W.

Published
2023
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26. Growth, structure refinement, thermal expansion and optical spectroscopy of Tm3+-doped MgMoO4

Author

Kirill Subbotin, Anatolii Titov, Denis Lis, Yulia Zimina, Yana Didenko, Ghassen Zin Elabedine, Kirill Eremeev, Rosa Maria Solé, Magdalena Aguiló, Pavel Volkov, Pavel Popov, Elena Chernova, Francesc Díaz, Patrice Camy, Pavel Loiko, and Xavier Mateos

Subjects
Inorganic Chemistry, Organic Chemistry, Electrical and Electronic Engineering, Physical and Theoretical Chemistry, Atomic and Molecular Physics, and Optics, Spectroscopy, Electronic, Optical and Magnetic Materials
Published
2023
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31. Tm,Ho:Ca(Gd,Lu)AlO4 crystals: Crystal growth, structure refinement and Judd-Ofelt analysis

Author

Zhongben Pan, Pavel Loiko, Sami Slimi, Hualei Yuan, Yicheng Wang, Yongguang Zhao, Patrice Camy, Elena Dunina, Alexey Kornienko, Liudmila Fomicheva, Li Wang, Weidong Chen, Uwe Griebner, Valentin Petrov, Rosa Maria Solé, Francesc Díaz, Magdalena Aguiló, Xavier Mateos, Shandong University, Max-Born Institute for Nonlinear Optics and Short Pulse Spectroscopy (MBI), Optique, Matériaux et Laser (OML), Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Departament de Química Física i Inorganica, Universitat Rovira i Virgili, Universitat Rovira i Virgili, China Academy of Engineering Physics (CAEP), Vitebsk State Technological University, and Belarusian State University

Subjects
Judd-Ofelt theory, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Czochralski growth, Optical absorption, Biophysics, Structure refinement, Raman spectra, General Chemistry, Condensed Matter Physics, Biochemistry, Aluminate crystals, Atomic and Molecular Physics, and Optics
Abstract

International audience; Mixed” calcium rare-earth aluminate laser host crystals Ca(Gd,Lu)AlO4 (CALGLO) with up to 10.8 at.% Lu codoped with Tm3+ and Ho3+ ions are grown by the Czochralski method along the [001] direction. The segregation of rare-earth ions is studied. The crystal structure is refined by the Rietveld method. Tm,Ho:Ca(Gd,Lu)AlO4 crystallizes in the tetragonal system (sp. gr. I4/mmm) exhibiting a K2NiF4 type structure. The lattice constants are a = 3.6585(6) Å and c = 11.9660(9) Å for a crystal with a composition of CaGd0.8947Lu0.0551Tm0.0448Ho0.0054AlO4. The stability of Ca(Gd,Lu)AlO4 solid-solutions is discussed. The polarized Raman spectra are measured, revealing a most intense mode at 311 cm−1 and a maximum phonon frequency of ∼650 cm−1. The polarized absorption spectra are measured. The transition intensities for the Ho3+ ion are analyzed using the modified Judd-Ofelt theory accounting for configuration interaction.

Published
2022
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32. Diode-pumped SESAM mode-locked Yb:(Y,Gd)AlO

Author

Wen-Ze, Xue, Zhang-Lang, Lin, Huang-Jun, Zeng, Ge, Zhang, Peixiong, Zhang, Zhenqiang, Chen, Zhen, Li, Valentin, Petrov, Pavel, Loiko, Xavier, Mateos, Haifeng, Lin, Yongguang, Zhao, Li, Wang, and Weidong, Chen

Abstract

We report on the continuous-wave (CW) and mode-locked (ML) laser performance of an Yb

Published
2022

33. SESAM mode-locked Yb:Sr

Author

Shijia, Sun, Huang-Jun, Zeng, Zhang-Lang, Lin, Wen-Ze, Xue, Ge, Zhang, Zhoubin, Lin, Valentin, Petrov, Haifeng, Lin, Pavel, Loiko, Xavier, Mateos, Yongguang, Zhao, Bing, Teng, Li, Wang, and Weidong, Chen

Abstract

We demonstrate the first sub-40 fs soliton pulse generation from a diode-pumped Yb:Sr

Published
2022

34. Diode-pumped mode-locked Yb:BaF

Author

Wen-Ze, Xue, Zhang-Lang, Lin, Huang-Jun, Zeng, Ge, Zhang, Pavel, Loiko, Liza, Basyrova, Abdelmjid, Benayad, Patrice, Camy, Valentin, Petrov, Xavier, Mateos, Li, Wang, and Weidong, Chen

Abstract

We report on a continuous-wave (CW) and passively mode-locked operation of a fluorite-type Yb:BaF

Published
2022

35. Soliton mode-locked Yb:Ca

Author

Huang-Jun, Zeng, Zhang-Lang, Lin, Wen-Ze, Xue, Ge, Zhang, Yujin, Chen, Zhongben, Pan, Valentin, Petrov, Pavel, Loiko, Xavier, Mateos, Yongguang, Zhao, Haifeng, Lin, Li, Wang, and Weidong, Chen

Abstract

We report on a soliton mode-locked Yb:Ca

Published
2022

36. In-band pumped Tm,Ho:LiYF

Author

Pavel, Loiko, Esrom, Kifle, Gurvan, Brasse, Romain, Thouroude, Florent, Starecki, Abdelmjid, Benayad, Alain, Braud, Mathieu, Laroche, Sylvain, Girard, Hervé, Gilles, and Patrice, Camy

Abstract

A 4.5 at.% Tm, 0.5 at.% Ho:LiYF

Published
2022

38. Structure and luminescent properties of Dy3+ activated NaLa9(SiO4)6O2 yellow-emitting phosphors for application in white LEDs

Author

Sami Slimi, Pavel Loiko, Kirill Bogdanov, Anna Volokitina, Rosa Maria Solé, Magdalena Aguiló, Francesc Díaz, Ezzedine Ben Salem, Xavier Mateos, Universitat Rovira i Virgili, Optique, Matériaux et Laser (OML), Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), ITMO University [Russia], Département de Mathématiques Physique de l’IPEIM [Monastir], Institut Préparatoire aux Etudes d'Ingénieurs de Monastir (IPEIM), and Université de Monastir - University of Monastir (UM)-Université de Monastir - University of Monastir (UM)

Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Mechanics of Materials, Mechanical Engineering, Materials Chemistry, Metals and Alloys
Abstract

International audience; A series of NaLa9-xDyx(SiO4)6O2 (NLSO:xDy, x = 0 – 0.3) apatitephosphors were synthesized by solid-state reaction at 1100 °C. Their crystalstructure, morphology and particle size distribution, electronic structure, Ramanspectra, as well as concentration- and temperature-dependent luminescentproperties were investigated for the first time. The crystal structure is refined by theRietveld method. Undoped NLSO is hexagonal (space group P63/m – C26h) withlattice constants a = b = 9.6917(3) Å and c = 7.1836(4) Å. Dy3+ ions substitute for theLa3+ ones in two types of sites. The first-principle calculations for undoped NLSOreveal an indirect bandgap of 5.06 eV. The photoluminescence properties wereinvestigated in detail through the measurements of the emission spectra andluminescence decay curves. The NLSO:0.2Dy phosphor exhibited the typical Dy3+emission corresponding to 4F9/2 →6HJ transitions, among which the hypersensitiveelectric-dipole transition 4F9/2→6H13/2 (571 nm) dominates in the spectrum leading toyellow emission color with CIE chromaticity coordinates of (0.469, 0.495) and acorrelated color temperature of 3150 K. The concentration quenching mechanismfor Dy3+ ions was investigated. Excellent thermal stability was found for this newapatite phosphor. The obtained results indicated that NLSO:xDy apatites arepromising as potential yellow emitting phosphors for applications in w-LEDs.

Published
2022
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39. Polarized spectroscopy and SESAM mode-locking of Tm,Ho:CALGO

Author

Yicheng Wang, Pavel Loiko, Yongguang Zhao, Zhongben Pan, Weidong Chen, Mark Mero, Xiaodong Xu, Jun Xu, Xavier Mateos, Arkady Major, Mircea Guina, Valentin Petrov, Uwe Griebner, Tampere University, Physics, Max-Born Institute for Nonlinear Optics and Short Pulse Spectroscopy (MBI), Optique, Matériaux et Laser (OML), Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Jiangsu Normal University (JSNU), Tongji University, Universitat Rovira i Virgili, University of Manitoba [Winnipeg], and Tampere University of Technology [Tampere] (TUT)

Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], 114 Physical sciences, Atomic and Molecular Physics, and Optics
Abstract

A Tm,Ho:CALGO laser passively mode-locked by a GaSb-based SESAM generated pulses as short as 52 fs at a central wavelength of 2015 nm with a broad spectral bandwidth of 82 nm (full width at half maximum) owing to the combined gain profiles of both dopants for σ-polarized light. The average output power reached 376 mW at a repetition rate of 85.65 MHz. In the continuous-wave regime, the laser was power scaled up to 1.01 W at 2080.6 nm with a slope efficiency of 32.0%, a laser threshold of 155 mW and π-polarized emission. Polarized spectroscopic properties of Ho3+ ions in singly doped and codoped CALGO crystals were revisited to explain the observed laser performance.

Published
2022
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40. Tailoring Broadband Emission Properties of Tm3+-Doped Solid-Solution Sesquioxide Laser Ceramics in the System Y2O3-Lu2O3-Sc2O3

Author

Kirill Eremeev, Pavel Loiko, Stanislav Balabanov, Timofey Evstropov, Dmitry Permin, Olga Postnikova, Patrice Camy, and Alain Braud

Abstract

Broadband emission properties of Tm3+-doped parent and binary / ternary solid-solution sesquioxide laser ceramics of the system Y2O3-Lu2O3-Sc2O3 were studied with a goal of developing materials capable of generating ultrashort pulses at ~2 μm.

Published
2022
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41. Cryogenic Laser Operation of Ytterbium-Doped CaF2, SrF2 and BaF2 Crystals

Author

Pavel Loiko, Jean-Louis Doualan, Abdelmjid Benayad, Alain Braud, and Patrice Camy

Abstract

We report on a comparative study of low-temperature spectroscopy and cryogenic (77-K) free-running and tunable laser operation of three Yb3+-doped fluorite-type crystals, CaF2, SrF2 and BaF2. 10-W diode-pumped cryogenic Yb:CaF2 laser is also developed.

Published
2022
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42. Growth, structure, and polarized spectroscopy of monoclinic Er 3+ :MgWO 4 crystal

Author

Lizhen Zhang, Liza Basyrova, Pavel Loiko, Patrice Camy, Zhoubin Lin, Ge Zhang, Sami Slimi, Rosa Maria Solé, Xavier Mateos, Magdalena Aguiló, Francesc Díaz, Elena Dunina, Alexey Kornienko, Uwe Griebner, Valentin Petrov, Li Wang, Weidong Chen, Fuzhou University [Fuzhou], École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU), Optique, Matériaux et Laser (OML), Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Universitat Rovira i Virgili, Vitebsk State Technological University, and Max-Born Institute for Nonlinear Optics and Short Pulse Spectroscopy (MBI)

Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Electronic, Optical and Magnetic Materials
Abstract

We report on the growth, structure, and polarized spectroscopy of a novel promising laser crystal, erbium-doped magnesium monotungstate, Er3+:MgWO4. 1.01 t.% Er3+:MgWO4 was grown by the Top-Seeded Solution Growth method using Na2WO4 as a solvent. The crystal structure was refined by the Rietveld method. Er3+:MgWO4 belongs to the monoclinic class (sp. gr. P2/c, wolframite-type structure, lattice parameters: a = 4.6939(6) Å, b = 5.6747(4) Å, c = 4.9316(6) Å and β = 90.7858(4) Å. The transition intensities for Er3+ ions were determined using the Judd-Ofelt theory accounting for an intermediate configuration interaction (ICI). Er3+ ions in MgWO4 exhibit intense, strongly polarized and broad absorption and emission bands owing to their accommodation in distorted low-symmetry sites (C2). The stimulated-emission cross-section for the 4I13/2 → 4I15/2 transition is 0.31×10−20 cm2 at 1637 nm (light polarization: E || b ). The radiative lifetime of the 4I13/2 state is 4.85 ± 0.05 ms. The multiphonon non-radiative relaxation for Er3+ excited multiplets is quantified. Er3+ ions in MgWO4 feature large Stark splitting of the ground-state, ΔE(4I15/2) = 435 cm-1. Er3+:MgWO4 is attractive for low-threshold lasers at ∼1.64 µm.

Published
2022
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43. Structure, optical properties and preferential site substitution of Eu$^{3+}$ activated Ca$_8$NaBi(PO$_4$)$_6$F$_2$ red emitting phosphors prepared by modified Pechini process

Author

Magdalena Aguiló, Sami Slimi, Pavel Loiko, Kirill Bogdanov, Francesc Díaz, Ezzedine Ben Salem, Xavier Mateos, Anna Volokitina, Rosa Maria Solé, Universitat Rovira i Virgili, Université de Monastir - University of Monastir (UM), Optique, Matériaux et Laser (OML), Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and National Research University of Information Technologies, Mechanics and Optics [St. Petersburg] (ITMO)

Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Materials science, Quenching (fluorescence), Doping, Biophysics, Phosphor, General Chemistry, Activation energy, Color temperature, Condensed Matter Physics, Biochemistry, Atomic and Molecular Physics, and Optics, symbols.namesake, Crystallography, symbols, Thermal stability, Raman spectroscopy, Luminescence
Abstract

International audience; Eu3+-doped and undoped Ca8NaBi(PO4)6F2:xEu (x = 0.01 – 0.5) apatite phosphors have been synthesized at 900 °C by the modified Pechini process.Their structural and morphological characteristics were determined by XRD, TEM and Raman spectroscopy. The structure of the host matrix was refined by the Rietveld method: Ca8NaBi(PO4)6F2 crystallizes in hexagonal class, sp. gr. P63/m, a = b =9.3980(6) Å, c = 6.9039(9) Å and γ = 120°). The electronic structure was simulated revealing an indirect bandgap of 3.46 eV. Eu3+ ions in the host matrix replace for theBi3+ ones in two types of sites: M1 (C3 symmetry and IX-fold oxygen coordination) and M2 (CS symmetry and VII-fold coordination by one fluoride and six oxygens). The doping induces a redistribution of Eu3+ ions over the M1 and M2 sites in favor of the former species. The transition probabilities for Eu3+ ions in M2 sites were determined using the Judd-Ofelt theory yielding a radiative lifetime of 2.21 ms. It was found that phosphors exhibit relatively weak luminescence quenching. The CIE 1931 color coordinates for the compound with x = 0.35 Eu are (0.648,0.352) falling in the red region and corresponding to a correlated color temperature of 2919 K and a color purity of >96%. The thermal stability of the phosphor was studied until 400 °C (the determined activation energy is 0.70 eV) indicating a redistribution of ions in favor of the M2 sites at high temperatures. Ca8NaBi(PO4)6F2:xEu apatites are promising as red phosphors for white-light LEDs.

Published
2022
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44. Kerr-lens mode-locked Yb:CLNGG laser

Author

Zhang-Lang Lin, Huang-Jun Zeng, Wen-Ze Xue, Ge Zhang, Valentin Petrov, Pavel Loiko, Xavier Mateos, Junhai Liu, Haohai Yu, Huaijin Zhang, Haifeng Lin, Li Wang, and Weidong Chen

Abstract

We report on a Kerr-lens mode-locked Yb:CLNGG laser generating 35-fs pulses at 1060.2 nm with an average output power of 85 mW at a pulse repetition rate of ~77.7 MHz.

Published
2022
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45. Diode-Pumped SESAM Mode-Locked Yb:YAB Laser

Author

Huang-Jun Zeng, Zhang-Lang Lin, Wen-Ze Xue, Ge Zhang, Yujin Chen, Yidong Huang, Pavel Loiko, Xavier Mateos, Li Wang, Weidong Chen, and Valentin Petrov

Abstract

We report on a diode-pumped mode-locked Yb-laser based on the non-centrosymmetric YAl3(BO3)4 host-crystal generating 56-fs pulses at 1044.6 nm with an average output power of 76 mW at a pulse repetition rate of ~67.5 MHz.

Published
2022
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46. Erbium-Doped Fluorite-Type Crystals for 2.8 µm Lasers

Author

Simone Normani, Liza Basyrova, Pavel Loiko, Abdelmjid Benayad, Alain Braud, Elena Dunina, Liudmila Fomicheva, Alexey Kornienko, Ammar Hideur, and Patrice Camy

Abstract

Spectroscopy and mid-infrared laser operation of Er3+-doped low-phonon-energy fluorite- type crystals, MF2 (M = Ca, Sr, Ba, Ca/Sr and Ba/Sr) were studied. The Er3+:CaF2 laser generated 702 mW at 2.80 μm with a 37.9% slope efficiency.

Published
2022
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47. Sub-50 fs Diode-Pumped Mode-Locked Yb:SrF2 Laser

Author

Wen-Ze Xue, Zhang-Lang Lin, Huang-Jun Zeng, Ge Zhang, Pavel Loiko, Abdelmjid Benayad, Alain Braud, Patrice Camy, Xavier Mateos, Valentin Petrov, Li Wang, and Weidong Chen

Abstract

We report on a diode-pumped SESAM mode-locked Yb:SrF2 laser generating 49 fs pulses at 1058 nm with an average output power of 117 mW at a pulse repetition rate of ~75.9 MHz.

Published
2022
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48. 32-fs Kerr-lens mode-locked Yb:GdYCOB laser

Author

Huang-Jun Zeng, Zhang-Lang Lin, Haifeng Lin, Wen-Ze Xue, Ge Zhang, Lizhen Zhang, Zhoubin Lin, Valentin Petrov, Pavel Loiko, Xavier Mateos, Li Wang, and Weidong Chen

Abstract

We demonstrate a diode-pumped Kerr-lens mode-locked Yb:GdYCOB laser delivering 32-fs pulses at 1052.4 nm with an average power of 51 mW. The maximum average output power is scaled to 189 mW for 35-fs pulses.

Published
2022
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49. Semiconductor saturable absorber mirror mode-locked Yb:YAP laser

Author

Zhang-Lang Lin, Wen-Ze Xue, Huang-Jun Zeng, Ge Zhang, Yongguang Zhao, Xiaodong Xu, Jun Xu, Pavel Loiko, Xavier Mateos, Haifeng Lin, Valentin Petrov, Li Wang, Weidong Chen, Fuzhou University [Fuzhou], Jiangsu Normal University (JSNU), Tongji University, Optique, Matériaux et Laser (OML), Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Universitat Rovira i Virgili, Shenzhen University [Shenzhen], and Max-Born Institute for Nonlinear Optics and Short Pulse Spectroscopy (MBI)

Subjects
Fiber lasers, Semiconductor lasers, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Optical pumping, Mode-locked fiber lasers, Atomic and Molecular Physics, and Optics, Pulse repetition rate, Laser mirrors
Abstract

International audience; We report on sub-30 fs pulse generation from a semiconductor saturable absorber mirror mode-locked Yb:YAP laser. Pumping by a spatially single-mode Yb fiber laser at 979 nm, soliton pulses as short as 29 fs were generated at 1091 nm with an average output power of 156 mW and a pulse repetition rate of 85.1 MHz. The maximum output power of the mode-locked Yb:YAP laser amounted to 320 mW for slightly longer pulses (32 fs) at an incident pump power of 1.52 W, corresponding to a peak power of 103 kW and an optical efficiency of 20.5%. To the best of our knowledge, this result represents the shortest pulses ever achieved from any solid-state Yb laser mode-locked by a slow, i.e., physical saturable absorber.

Published
2022
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50. Sub-30 fs Kerr-lens mode-locked Yb:YAP laser

Author

Weidong Chen, Zhang-Lang Lin, Wen-Ze Xue, Huang-Jun Zeng, Ge Zhang, Pavel Loiko, Yongguang Zhao, Xiaodong Xu, Jun Xu, Xavier Mateos, Haifeng Lin, Li Wang, and Valentin Petrov

Abstract

We report on a Kerr-lens mode-locked Yb:YAlO3 laser generating 24 fs pulses at 1085 nm with an average output power of 186 mW at a pulse repetition rate of ~87.5 MHz.

Published
2022
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