Alain Brenier - Academia.edu (original) (raw)

Papers by Alain Brenier

CrystEngComm, 2018

The convex interface shape in Kyropoulos-grown crystals is suggested to be responsible for the sc... more The convex interface shape in Kyropoulos-grown crystals is suggested to be responsible for the scattering defect in large diameter titanium sapphire.

Inorganic Chemistry, 2016

Structure and Bonding, 2012

ABSTRACT As a laser host, Borates possess favorable chemical and physical characteristics as well... more ABSTRACT As a laser host, Borates possess favorable chemical and physical characteristics as well as higher damnification threshold. Especially, Borates usually have higher nonlinear optical efficiency resulted from its B–O structure. When doped with active ions, Borates can serve as a self-frequency conversion multifunction laser medium. For example, rare-earth ions and Cr3+-doped RX3(BO3)4, especially GdAl3(BO3)4 and TmAl3(BO3)4, are typical self-frequency conversion multifunction laser crystals. After wide surveys of known research on the growth, crystal structure, and properties including thermal, optical, and spectral characteristics and laser property, this chapter reviews the recent advances in the development of these crystals. Self-frequency conversion laser technology including the self-frequency doubling, self-difference-frequency mixing and self-sum-frequency mixing methods were dealt with. As a result, the laser outputs with high efficiency at various wavelengths ranged from UV to IR have been achieved.

Physical Review B, 1994

A study of the Ho'+ 2-pm laser emission in Gd3Ga50» using Yb'+ and Tm'+ ions as sensitizers is pr... more A study of the Ho'+ 2-pm laser emission in Gd3Ga50» using Yb'+ and Tm'+ ions as sensitizers is presented. We show by quantum-yield measurements that up-conversion energy losses are weak in the triply doped crystal. Models that describe the excited-state dynamics for both up-and down-conversion processes are given.

Journal de Physique, 1989

2014 La dynamique des états excités de LiYF4 faiblement dopé en ions Tm3+ est tout d'abord analys... more 2014 La dynamique des états excités de LiYF4 faiblement dopé en ions Tm3+ est tout d'abord analysée. Les processus de fluorescence Stokes sont interprétés en tenant compte des nombreuses coïncidences entre les fluorescences émises par les ions Tm3+ et en considérant deux types de sites. Plus compliquée, la dynamique de fluorescence anti-Stokes est décrite seulement très brièvement. Les transferts d'énergie Tm3+ ~ Ho3+ sont ensuite étudiés dans des systèmes codopés. Des transferts 3F4 ~ 5I7 très efficaces à température ambiante sont rapportés alors que le transfert retour 5I7 ~ 3F4 disparaît complètement aux basses températures (T 200 K). Lorsque les ions Tm3+ sont excités dans leur niveau 3H4, on montre que trois voies de désexcitation sont possibles : une désexcitation à l'intérieur d'un même centre Tm3 +, une relaxation croisée entre ions Tm3+ adjacents du type 3H4, 3H6 ~ 3F4, 3F4 et un transfert direct Tm3+ ~ Ho3 +. Le premier mécanisme est très faible et les deux autres sont en compétition, le dernier dominant largement à haute concentration en ions Ho3+.

J. Mater. Chem. C, 2014

RE-doped AgM(IO3)4metal iodates are of interest as potential laser and self-doubled materials.

High-Power Gas and Solid State Lasers, 1994

Solid State Lasers IV, 1993

ABSTRACT The possibility of sensitization of rare-earth laser active ions with infrared (especial... more ABSTRACT The possibility of sensitization of rare-earth laser active ions with infrared (especially two- micron) emission by Fe3+ is discussed. The spectroscopic and luminescence decay measurements on Fe, Tm or Fe:Tm doped GGG or YAG show that a very efficiency energy transfer from Fe3+ in tetrahedral sites to Tm3+ takes place showing prospects for new sensitization schemes.

Optics Express, 2005

The passively Q-switched laser characteristics of a quasi-threelevel Yb 3+ :Gd 3 Ga 5 O 12 (Yb 3+... more The passively Q-switched laser characteristics of a quasi-threelevel Yb 3+ :Gd 3 Ga 5 O 12 (Yb 3+ :GGG) crystal with Cr 4+ :YAG saturable absorbers are studied experimentally and theoretically. The pulse parameters under different experimental conditions are measured. Some characteristics different from those of a four-level system are found. In the theoretical aspect, taking into account the spatial distributions of the pump light and intracavity laser mode, the rate equations describing the single Q-switched pulse characteristics of a quasi-three-level system are obtained. The obtained theoretical results are in fair agreement with the experimental results. Some topics such as the influence of the pumping power, the selection of the pump beam size, the optimal combination of output coupler reflectivity and saturable absorber initial transmission, the influence of the excited absorption of the saturable absorber, are discussed.

Optics Communications, 2003

... Yehoshua Kalisky a , Gerard Métrat b , Noelle Muhlstein b , Alain Brenier Corresponding Autho... more ... Yehoshua Kalisky a , Gerard Métrat b , Noelle Muhlstein b , Alain Brenier Corresponding Author Contact Information , E-mail The Corresponding Author , b and Georges Boulon b. ... 12. B. Zysset, I. Biaggio and P. Gunter. J. Opt. Soc. Am. B 9 3 (1992), p. 380. Full Text via CrossRef. ...

Journal of the Optical Society of America B, 2003

Diode-pumped laser action at 1.34 m from the Nd 3ϩ :Ca 3 Ga 2 Ge 3 O 12 system is demonstrated an... more Diode-pumped laser action at 1.34 m from the Nd 3ϩ :Ca 3 Ga 2 Ge 3 O 12 system is demonstrated and the physical parameters of relevance in laser dynamics reported. The pump-to-infrared conversion efficiency has been investigated as a function of both Nd 3ϩ concentration and output mirror transmittance. From the analysis of laser curves it has been demonstrated that the low laser efficiencies arise from the inhomogeneous line broadening of emission bands induced by multicenter distribution. This analysis has also been employed to determine the ratio between inhomogeneous and homogeneous line broadening (⌬ inh /⌬ h Ϸ 2.5), the result being in good agreement with that obtained from spectroscopy. Other mechanisms that could affect the extraction efficiency, such as excited-state absorption and energy-transfer upconversion, have also been evaluated, the results indicating that their influence in laser dynamics is negligible. Finally, we also report on the influence of multicenter distribution on the spectral shape of the 1.34-m output laser radiation.

Journal of the Optical Society of America B, 2011

Calcium aluminosilicate" (CAS) and "low silica calcium aluminosilicate" (LSCAS) OH − free glasses... more Calcium aluminosilicate" (CAS) and "low silica calcium aluminosilicate" (LSCAS) OH − free glasses have demonstrated a good potential for solid-state laser media and luminophore hosts due to good thermal, optical, and mechanical properties. Some examples have already been shown with Nd 3þ , Er 3þ , Ce 3þ , and Ti 3þ luminescent ions. In this work, Yb 3þ rare-earth laser ions have been introduced into the two series of CAS and LSCAS glasses melted at 1600°C in a vacuum furnace and have been optically characterized and compared. Special attention has been devoted to both structural characterization in relationship with spectroscopic properties and concentration quenching phenomenon in relationship with laser parameters. Laser measurements at 1037 nm have been successfully performed under laser diode pumping.

Optical Materials, 2007

Square-shaped blue single crystals of nickel-doped magnesium aluminum spinel have been pulled dow... more Square-shaped blue single crystals of nickel-doped magnesium aluminum spinel have been pulled down from the melt, by the micropulling-down method. The absorption spectra of doped samples show three broad absorption bands. According to the absorption map and the chemical analysis of these crystals, the effective segregation coefficients of Ni 2+ in MgAl 2 O 4 at low doping concentration (C Ni h 2 mol%) were calculated to be less than the unity, due to the vaporization behavior of NiO. Strong infrared broad emission in the eye-safe region peaking at 1.3 lm have been systematically investigated under high-intensity pulsed Nd:YAG laser excitation in the red region. The suitable absorption for InGaAs laser-diode pumping combined with long decay time of the infrared emissions and the good thermal properties of MgAl 2 O 4 make Ni 2+-MgAl 2 O 4 a promising laser crystal.

Optical Materials, 2003

Diode pumping of a stress-free, Nd(5 at.%):KGd(WO 4) 2 , grown by top nucleated floating crystal ... more Diode pumping of a stress-free, Nd(5 at.%):KGd(WO 4) 2 , grown by top nucleated floating crystal (TNFC) method, is presented. The diode-pumped laser was operated both in the free-running and passively Q-switched operating modes. Under optimized conditions of resonator and optics, the disk (1.3 mm in thickness), produced at room temperature an efficient free-running, TEM 00 output with maximum power of 0.4 W, with 75% slope efficiency and 51% total laser efficiency. Under slightly different experimental conditions the laser was passively Q-switched by using Cr 4þ :YAG as saturable absorber. The passively Q-switched laser produced modulated pulses at average frequencies in the range of 10-20 kHz, with pulsewidth of %180 ns, with an average output power obtained was 30 mW at the maximum pumping power level. The results presented here indicate the potential Nd:KGd(WO 4) 2 crystals grown by TNFC growth method, as candidates for concentrated, stress free diode-pumped microlasers in a large variety of wavelengths, including the eyesafe range.

Optical Materials, 2003

In the self-frequency doubling or summing laser, the fact that the same crystal is used for laser... more In the self-frequency doubling or summing laser, the fact that the same crystal is used for laser action and nonlinear frequency conversion leads to compact and robust devices which can be diode pumped. We present the results obtained with the main crystals involved in these devices at the present time: GdCOB:Nd, NYAB and NGAB. High efficiency is obtained from NYAB

Journal of Physics: Condensed Matter, 2006

Page 1. Optical multi-sites of Nd3+-doped CaMoO4 induced by Nb5+ charge compensator This article ... more Page 1. Optical multi-sites of Nd3+-doped CaMoO4 induced by Nb5+ charge compensator This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2006 J. Phys.: Condens. Matter 18 7883 (http://iopscience.iop.org/0953-8984/18/34/003) ...

Journal of Physics: Condensed Matter, 2010

The spectroscopic characteristics of the α-ZnAl(2)S(4) wide bandgap semiconductor doped with Ti i... more The spectroscopic characteristics of the α-ZnAl(2)S(4) wide bandgap semiconductor doped with Ti ions are investigated. It is shown, that the ZnAl(2)S(4):Ti spinel-type crystals exhibit luminescence in the IR spectral range 0.8-1.4 µm. The observed spectroscopic characteristics are assigned to the emission bands arising from the ligand -Ti(4+) charge transfer for octahedral sites of titanium that is in agreement with the experimental evidence for the absence of the EPR signal from Ti ions. A qualitative explanation of the experimental data is given.

Journal of Applied Physics, 2005

Nd x La 2 − x Ca B 10 O 19 crystals with different Nd3+ concentrations were grown by the high-tem... more Nd x La 2 − x Ca B 10 O 19 crystals with different Nd3+ concentrations were grown by the high-temperature flux method. Room-temperature spectroscopy, i.e., absorption, emission, and lifetime measurements, was used to obtain the signatures of two inequivalent Nd3+ centers in the crystal host. They are attributed to Nd3+ substitution of both La3+ and Ca2+ sites. Nonradiative energy losses were estimated with the help of the Judd-Ofelt analysis. Self-frequency doubling of the F3∕24→I11∕24 Nd3+ laser channel with 5% efficiency was demonstrated in the XZ principal plane. It is clearly shown that self-frequency doubling can occur from two inequivalent luminescent centers.

CrystEngComm, 2018

The convex interface shape in Kyropoulos-grown crystals is suggested to be responsible for the sc... more The convex interface shape in Kyropoulos-grown crystals is suggested to be responsible for the scattering defect in large diameter titanium sapphire.

Inorganic Chemistry, 2016

Structure and Bonding, 2012

ABSTRACT As a laser host, Borates possess favorable chemical and physical characteristics as well... more ABSTRACT As a laser host, Borates possess favorable chemical and physical characteristics as well as higher damnification threshold. Especially, Borates usually have higher nonlinear optical efficiency resulted from its B–O structure. When doped with active ions, Borates can serve as a self-frequency conversion multifunction laser medium. For example, rare-earth ions and Cr3+-doped RX3(BO3)4, especially GdAl3(BO3)4 and TmAl3(BO3)4, are typical self-frequency conversion multifunction laser crystals. After wide surveys of known research on the growth, crystal structure, and properties including thermal, optical, and spectral characteristics and laser property, this chapter reviews the recent advances in the development of these crystals. Self-frequency conversion laser technology including the self-frequency doubling, self-difference-frequency mixing and self-sum-frequency mixing methods were dealt with. As a result, the laser outputs with high efficiency at various wavelengths ranged from UV to IR have been achieved.

Physical Review B, 1994

A study of the Ho'+ 2-pm laser emission in Gd3Ga50» using Yb'+ and Tm'+ ions as sensitizers is pr... more A study of the Ho'+ 2-pm laser emission in Gd3Ga50» using Yb'+ and Tm'+ ions as sensitizers is presented. We show by quantum-yield measurements that up-conversion energy losses are weak in the triply doped crystal. Models that describe the excited-state dynamics for both up-and down-conversion processes are given.

Journal de Physique, 1989

2014 La dynamique des états excités de LiYF4 faiblement dopé en ions Tm3+ est tout d'abord analys... more 2014 La dynamique des états excités de LiYF4 faiblement dopé en ions Tm3+ est tout d'abord analysée. Les processus de fluorescence Stokes sont interprétés en tenant compte des nombreuses coïncidences entre les fluorescences émises par les ions Tm3+ et en considérant deux types de sites. Plus compliquée, la dynamique de fluorescence anti-Stokes est décrite seulement très brièvement. Les transferts d'énergie Tm3+ ~ Ho3+ sont ensuite étudiés dans des systèmes codopés. Des transferts 3F4 ~ 5I7 très efficaces à température ambiante sont rapportés alors que le transfert retour 5I7 ~ 3F4 disparaît complètement aux basses températures (T 200 K). Lorsque les ions Tm3+ sont excités dans leur niveau 3H4, on montre que trois voies de désexcitation sont possibles : une désexcitation à l'intérieur d'un même centre Tm3 +, une relaxation croisée entre ions Tm3+ adjacents du type 3H4, 3H6 ~ 3F4, 3F4 et un transfert direct Tm3+ ~ Ho3 +. Le premier mécanisme est très faible et les deux autres sont en compétition, le dernier dominant largement à haute concentration en ions Ho3+.

J. Mater. Chem. C, 2014

RE-doped AgM(IO3)4metal iodates are of interest as potential laser and self-doubled materials.

High-Power Gas and Solid State Lasers, 1994

Solid State Lasers IV, 1993

ABSTRACT The possibility of sensitization of rare-earth laser active ions with infrared (especial... more ABSTRACT The possibility of sensitization of rare-earth laser active ions with infrared (especially two- micron) emission by Fe3+ is discussed. The spectroscopic and luminescence decay measurements on Fe, Tm or Fe:Tm doped GGG or YAG show that a very efficiency energy transfer from Fe3+ in tetrahedral sites to Tm3+ takes place showing prospects for new sensitization schemes.

Optics Express, 2005

The passively Q-switched laser characteristics of a quasi-threelevel Yb 3+ :Gd 3 Ga 5 O 12 (Yb 3+... more The passively Q-switched laser characteristics of a quasi-threelevel Yb 3+ :Gd 3 Ga 5 O 12 (Yb 3+ :GGG) crystal with Cr 4+ :YAG saturable absorbers are studied experimentally and theoretically. The pulse parameters under different experimental conditions are measured. Some characteristics different from those of a four-level system are found. In the theoretical aspect, taking into account the spatial distributions of the pump light and intracavity laser mode, the rate equations describing the single Q-switched pulse characteristics of a quasi-three-level system are obtained. The obtained theoretical results are in fair agreement with the experimental results. Some topics such as the influence of the pumping power, the selection of the pump beam size, the optimal combination of output coupler reflectivity and saturable absorber initial transmission, the influence of the excited absorption of the saturable absorber, are discussed.

Optics Communications, 2003

... Yehoshua Kalisky a , Gerard Métrat b , Noelle Muhlstein b , Alain Brenier Corresponding Autho... more ... Yehoshua Kalisky a , Gerard Métrat b , Noelle Muhlstein b , Alain Brenier Corresponding Author Contact Information , E-mail The Corresponding Author , b and Georges Boulon b. ... 12. B. Zysset, I. Biaggio and P. Gunter. J. Opt. Soc. Am. B 9 3 (1992), p. 380. Full Text via CrossRef. ...

Journal of the Optical Society of America B, 2003

Diode-pumped laser action at 1.34 m from the Nd 3ϩ :Ca 3 Ga 2 Ge 3 O 12 system is demonstrated an... more Diode-pumped laser action at 1.34 m from the Nd 3ϩ :Ca 3 Ga 2 Ge 3 O 12 system is demonstrated and the physical parameters of relevance in laser dynamics reported. The pump-to-infrared conversion efficiency has been investigated as a function of both Nd 3ϩ concentration and output mirror transmittance. From the analysis of laser curves it has been demonstrated that the low laser efficiencies arise from the inhomogeneous line broadening of emission bands induced by multicenter distribution. This analysis has also been employed to determine the ratio between inhomogeneous and homogeneous line broadening (⌬ inh /⌬ h Ϸ 2.5), the result being in good agreement with that obtained from spectroscopy. Other mechanisms that could affect the extraction efficiency, such as excited-state absorption and energy-transfer upconversion, have also been evaluated, the results indicating that their influence in laser dynamics is negligible. Finally, we also report on the influence of multicenter distribution on the spectral shape of the 1.34-m output laser radiation.

Journal of the Optical Society of America B, 2011

Calcium aluminosilicate" (CAS) and "low silica calcium aluminosilicate" (LSCAS) OH − free glasses... more Calcium aluminosilicate" (CAS) and "low silica calcium aluminosilicate" (LSCAS) OH − free glasses have demonstrated a good potential for solid-state laser media and luminophore hosts due to good thermal, optical, and mechanical properties. Some examples have already been shown with Nd 3þ , Er 3þ , Ce 3þ , and Ti 3þ luminescent ions. In this work, Yb 3þ rare-earth laser ions have been introduced into the two series of CAS and LSCAS glasses melted at 1600°C in a vacuum furnace and have been optically characterized and compared. Special attention has been devoted to both structural characterization in relationship with spectroscopic properties and concentration quenching phenomenon in relationship with laser parameters. Laser measurements at 1037 nm have been successfully performed under laser diode pumping.

Optical Materials, 2007

Square-shaped blue single crystals of nickel-doped magnesium aluminum spinel have been pulled dow... more Square-shaped blue single crystals of nickel-doped magnesium aluminum spinel have been pulled down from the melt, by the micropulling-down method. The absorption spectra of doped samples show three broad absorption bands. According to the absorption map and the chemical analysis of these crystals, the effective segregation coefficients of Ni 2+ in MgAl 2 O 4 at low doping concentration (C Ni h 2 mol%) were calculated to be less than the unity, due to the vaporization behavior of NiO. Strong infrared broad emission in the eye-safe region peaking at 1.3 lm have been systematically investigated under high-intensity pulsed Nd:YAG laser excitation in the red region. The suitable absorption for InGaAs laser-diode pumping combined with long decay time of the infrared emissions and the good thermal properties of MgAl 2 O 4 make Ni 2+-MgAl 2 O 4 a promising laser crystal.

Optical Materials, 2003

Diode pumping of a stress-free, Nd(5 at.%):KGd(WO 4) 2 , grown by top nucleated floating crystal ... more Diode pumping of a stress-free, Nd(5 at.%):KGd(WO 4) 2 , grown by top nucleated floating crystal (TNFC) method, is presented. The diode-pumped laser was operated both in the free-running and passively Q-switched operating modes. Under optimized conditions of resonator and optics, the disk (1.3 mm in thickness), produced at room temperature an efficient free-running, TEM 00 output with maximum power of 0.4 W, with 75% slope efficiency and 51% total laser efficiency. Under slightly different experimental conditions the laser was passively Q-switched by using Cr 4þ :YAG as saturable absorber. The passively Q-switched laser produced modulated pulses at average frequencies in the range of 10-20 kHz, with pulsewidth of %180 ns, with an average output power obtained was 30 mW at the maximum pumping power level. The results presented here indicate the potential Nd:KGd(WO 4) 2 crystals grown by TNFC growth method, as candidates for concentrated, stress free diode-pumped microlasers in a large variety of wavelengths, including the eyesafe range.

Optical Materials, 2003

In the self-frequency doubling or summing laser, the fact that the same crystal is used for laser... more In the self-frequency doubling or summing laser, the fact that the same crystal is used for laser action and nonlinear frequency conversion leads to compact and robust devices which can be diode pumped. We present the results obtained with the main crystals involved in these devices at the present time: GdCOB:Nd, NYAB and NGAB. High efficiency is obtained from NYAB

Journal of Physics: Condensed Matter, 2006

Page 1. Optical multi-sites of Nd3+-doped CaMoO4 induced by Nb5+ charge compensator This article ... more Page 1. Optical multi-sites of Nd3+-doped CaMoO4 induced by Nb5+ charge compensator This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2006 J. Phys.: Condens. Matter 18 7883 (http://iopscience.iop.org/0953-8984/18/34/003) ...

Journal of Physics: Condensed Matter, 2010

The spectroscopic characteristics of the α-ZnAl(2)S(4) wide bandgap semiconductor doped with Ti i... more The spectroscopic characteristics of the α-ZnAl(2)S(4) wide bandgap semiconductor doped with Ti ions are investigated. It is shown, that the ZnAl(2)S(4):Ti spinel-type crystals exhibit luminescence in the IR spectral range 0.8-1.4 µm. The observed spectroscopic characteristics are assigned to the emission bands arising from the ligand -Ti(4+) charge transfer for octahedral sites of titanium that is in agreement with the experimental evidence for the absence of the EPR signal from Ti ions. A qualitative explanation of the experimental data is given.

Journal of Applied Physics, 2005

Nd x La 2 − x Ca B 10 O 19 crystals with different Nd3+ concentrations were grown by the high-tem... more Nd x La 2 − x Ca B 10 O 19 crystals with different Nd3+ concentrations were grown by the high-temperature flux method. Room-temperature spectroscopy, i.e., absorption, emission, and lifetime measurements, was used to obtain the signatures of two inequivalent Nd3+ centers in the crystal host. They are attributed to Nd3+ substitution of both La3+ and Ca2+ sites. Nonradiative energy losses were estimated with the help of the Judd-Ofelt analysis. Self-frequency doubling of the F3∕24→I11∕24 Nd3+ laser channel with 5% efficiency was demonstrated in the XZ principal plane. It is clearly shown that self-frequency doubling can occur from two inequivalent luminescent centers.