The Experts below are selected from a list of 47184 Experts worldwide ranked by ideXlab platform
Mireille Commandre - One of the best experts on this subject based on the ideXlab platform.
-
catastrophic nanosecond Laser induced Damage in the bulk of potassium titanyl phosphate crystals
Journal of Applied Physics, 2014Co-Authors: Frank Wagner, Jeanyves Natoli, Hassan Akhouayri, G Duchateau, Mireille CommandreAbstract:Due to its high effective nonlinearity and the possibility to produce periodically poled crystals, potassium titanyl phosphate (KTiOPO4, KTP) is still one of the economically important nonlinear optical materials. In this overview article, we present a large study on catastrophic nanosecond Laser induced Damage in this material and the very similar RbTiOPO4 (RTP). Several different systematic studies are included: multiple pulse Laser Damage, multi-wavelength Laser Damage in KTP, Damage resistance anisotropy, and variations of the Laser Damage thresholds for RTP crystals of different qualities. All measurements were carried out in comparable experimental conditions using a 1064 nm Q-switched Laser and some were repeated at 532 nm. After summarizing the experimental results, we detail the proposed model for Laser Damage in this material and discuss the experimental results in this context. According to the model, nanosecond Laser Damage is caused by light-induced generation of transient Laser-Damage precur...
-
catastrophic nanosecond Laser induced Damage in the bulk of potassium titanyl phosphate crystals
Journal of Applied Physics, 2014Co-Authors: Frank Wagner, Jeanyves Natoli, Hassan Akhouayri, G Duchateau, Mireille CommandreAbstract:Due to its high effective nonlinearity and the possibility to produce periodically poled crystals, potassium titanyl phosphate (KTiOPO4, KTP) is still one of the economically important nonlinear optical materials. In this overview article, we present a large study on catastrophic nanosecond Laser induced Damage in this material and the very similar RbTiOPO4 (RTP). Several different systematic studies are included: multiple pulse Laser Damage, multi-wavelength Laser Damage in KTP, Damage resistance anisotropy, and variations of the Laser Damage thresholds for RTP crystals of different qualities. All measurements were carried out in comparable experimental conditions using a 1064 nm Q-switched Laser and some were repeated at 532 nm. After summarizing the experimental results, we detail the proposed model for Laser Damage in this material and discuss the experimental results in this context. According to the model, nanosecond Laser Damage is caused by light-induced generation of transient Laser-Damage precursors which subsequently provide free electrons that are heated by the same nanosecond pulse. We also present a stimulated Raman scattering measurement and confront slightly different models to the experimental data. Finally, the physical nature of the transient Damage precursors is discussed and similarities and differences to Laser Damage in other crystals are pointed out.
-
multipulse Laser Damage in potassium titanyl phosphate statistical interpretation of measurements and the Damage initiation mechanism
Optical Engineering, 2012Co-Authors: Frank R Wagner, Laurent Gallais, Mireille Commandre, Anne Hildenbrand, Hassan Akhouayri, Celine Gouldieff, Jeanyves NatoliAbstract:Multipulse Laser-induced Damage is an important topic for many applications of nonlinear crystals. We studied multipulse Damage in X-cut KTiOPO4. Using a 6-ns Nd:YAG Laser with a weakly focused beam, a fatigue phenomenon was observed. We addressed whether this phenomenon necessarily implies material modifications. Two possible models were tested, both of them predicting increasing Damage probability with increasing pulse number while all material properties are kept constant. The first model, pulse energy fluctuations and depointing, increases the probed volume during multiple pulse experiments. The probability to cause Damage thus increases with increasing pulse number; however, this effect is too small to explain the observed fatigue. The second model assumes a constant single-shot Damage probability p1, so a multipulse experiment can be described by statistically independent resampling of the material. Very good agreement was found between the 2000-on-1 volume Damage data and this statistical multipulse model. Additionally, the spot size dependency of the Damage probability is well described by a precursor presence model. Supposing that Laser Damage precursors are transient, the presented data explain the experimental results without supposing material modifications.
-
femtosecond Laser Damage resistance of oxide and mixture oxide optical coatings
Optics Letters, 2012Co-Authors: Benoit Mangote, Laurent Gallais, Mireille Commandre, Marco Jupe, Lars Jensen, Andrius Melninkaitis, Detlev Ristau, Mathias Mende, Henrik Ehlers, Julius MirauskasAbstract:We report on the Laser Damage resistance of ion beam—sputtered oxide materials (Al2O3, Nb2O5, HfO2, SiO2, Ta2O5, ZrO2) and mixtures of Al2O3-SiO2, Nb2O5-SiO2, HfO2-SiO2, Ta2O5-SiO2, and ZrO2-SiO2, irradiated by single 500 fs pulses at 1030 nm. Laser-induced Damage threshold (LIDT), refractive index, and bandgaps of the single-layer coatings are measured. For pure oxide materials a linear evolution of the LIDT with bandgap is observed. The results are in accordance with our simulations based on photo-ionization and avalanche-ionization. In the case of mixtures, however, deviations from the previous behaviors are evidenced. The evolution of the LIDT as a function of the refractive index is analyzed, and an empirical description of the relation between refractive index and LIDT is proposed.
-
a high accuracy femto picosecond Laser Damage test facility dedicated to the study of optical thin films
Review of Scientific Instruments, 2012Co-Authors: Benoit Mangote, Laurent Gallais, Mireille Commandre, Myriam Zerrad, Fabien Lemarchand, Lihong Gao, Michel LequimeAbstract:A Laser Damage test facility delivering pulses from 100 fs to 3 ps and designed to operate at 1030 nm is presented. The different details of its implementation and performances are given. The originality of this system relies the online Damage detection system based on Nomarski microscopy and the use of a non-conventional energy detection method based on the utilization of a cooled CCD that offers the possibility to obtain the Laser induced Damage threshold (LIDT) with high accuracy. Applications of this instrument to study thin films under Laser irradiation are presented. Particularly the deterministic behavior of the sub-picosecond Damage is investigated in the case of fused silica and oxide films. It is demonstrated that the transition of 0–1 Damage probability is very sharp and the LIDT is perfectly deterministic at few hundreds of femtoseconds. The Damage process in dielectric materials being the results of electronic processes, specific information such as the material bandgap is needed for the interpretation of results and applications of scaling laws. A review of the different approaches for the estimation of the absorption gap of optical dielectric coatings is conducted and the results given by the different methods are compared and discussed. The LIDT and gap of several oxide materials are then measured with the presented instrument: Al2O3, Nb2O5, HfO2, SiO2, Ta2O5, and ZrO2. The obtained relation between the LIDT and gap at 1030 nm confirms the linear evolution of the threshold with the bandgap that exists at 800 nm, and our work expands the number of tested materials.A Laser Damage test facility delivering pulses from 100 fs to 3 ps and designed to operate at 1030 nm is presented. The different details of its implementation and performances are given. The originality of this system relies the online Damage detection system based on Nomarski microscopy and the use of a non-conventional energy detection method based on the utilization of a cooled CCD that offers the possibility to obtain the Laser induced Damage threshold (LIDT) with high accuracy. Applications of this instrument to study thin films under Laser irradiation are presented. Particularly the deterministic behavior of the sub-picosecond Damage is investigated in the case of fused silica and oxide films. It is demonstrated that the transition of 0–1 Damage probability is very sharp and the LIDT is perfectly deterministic at few hundreds of femtoseconds. The Damage process in dielectric materials being the results of electronic processes, specific information such as the material bandgap is needed for the inte...
Wanguo Zheng - One of the best experts on this subject based on the ideXlab platform.
-
advanced mitigation process amp for improving Laser Damage threshold of fused silica optics
Scientific Reports, 2016Co-Authors: Jin Huang, Xiaodong Jiang, Wanguo Zheng, Hongjie Liu, Feng Geng, Laixi Sun, Liang QiaoAbstract:The Laser Damage precursors in subsurface of fused silica (e.g. photosensitive impurities, scratches and redeposited silica compounds) were mitigated by mineral acid leaching and HF etching with multi-frequency ultrasonic agitation, respectively. The comparison of scratches morphology after static etching and high-frequency ultrasonic agitation etching was devoted in our case. And comparison of Laser induce Damage resistance of scratched and non-scratched fused silica surfaces after HF etching with high-frequency ultrasonic agitation were also investigated in this study. The global Laser induce Damage resistance was increased significantly after the Laser Damage precursors were mitigated in this case. The redeposition of reaction produce was avoided by involving multi-frequency ultrasonic and chemical leaching process. These methods made the increase of Laser Damage threshold more stable. In addition, there is no scratch related Damage initiations found on the samples which were treated by Advanced Mitigation Process.
-
reaction ion etching process for improving Laser Damage resistance of fused silica optical surface
Optics Express, 2016Co-Authors: Jin Huang, Xin Ye, Qingzhi Li, Xiaodong Jiang, Weidong Wu, Liming Yang, Wanguo ZhengAbstract:Laser induced Damage of fused silica optics occurs primarily on optical surface or subsurface resulting from various defects produced during polishing/grinding process. Many new kinds of surface treatment processes are explored to remove or control the defects on fused silica surface. In this study, we report a new application of reaction ion etching (RIE)-based surface treatment process for manufacture of high quality fused silica optics. The influence of RIE processes on Laser Damage resistance as a function of etching depth and the evolution of typical defects which are associated with Laser Damage performance were investigated. The results show that the impurity element defects and subsurface Damage on the samples surface were efficiently removed and prevented. Pure silica surface with relatively single-stable stoichiometry and low carbon atomic concentration was created during the etching. The Laser Damage resistance of the etched samples increased dramatically. The increase of roughness and ODC point defect with deeper etching are believed to be the main factors to limit further increase of the Damage resistance of fused silica. The study is expected to contribute to the development of fused silica optics with high resistance to Laser induced degradation in the future.
-
subsurface defects characterization and Laser Damage performance of fused silica optics during hf etched process
Optical Materials, 2014Co-Authors: Hongjie Liu, Jin Huang, Xiaodong Jiang, Xinda Zhou, Fengrui Wang, Xiaoyan Zhou, Zhan Sui, Wanguo ZhengAbstract:Abstract Subsurface defects of fused silica optics would vary with HF-etched process. In this paper, the subsurface defects characteristics of HF-etched fused silica optics and their effects on Laser induced Damage were investigated. The results suggest that most of metal impurities defects (especially Ce element) of fused silica optics can be dissolved in strong acid solution. Subsurface Damage can be removed by submerging fused silica optics in HF-based etchants. Laser Damage resistance is improved through the removal of metal impurities and subsurface Damage. Optical thermal absorption describes the Laser absorption characterization of fused silica subsurface layer. A good correlation between optical thermal absorption and Laser-induced Damage performance is shown in this paper. Laser Damage performance deteriorates when the HF-based etching depth exceeds one value, which can be explained by the impurities redeposition and surface roughness increase. Research results have a guiding significance for HF-based etching process technology of fused silica optics.
-
surface evolution and Laser Damage resistance of co2 Laser irradiated area of fused silica
Optics and Lasers in Engineering, 2011Co-Authors: W Dai, X Xiang, Y Jiang, Haijun Wang, Xiaodong Yuan, Wanguo ZhengAbstract:Abstract A 10.6 μm CO 2 Laser has been reported to effectively mitigate the Laser Damage growth of fused silica. Two zones of the Laser irradiated area are defined in this work: the distorted zone and the Laser affected zone. The parameters of the two zones are studied at different CO 2 Laser beam sizes, irradiation times, and powers by microscopy, profilometry, and photoelastic method. The results show that the diameter of Laser affected zone is almost completely determined by the Laser beam size and the distorted zone is associated with the mitigation range of CO 2 Laser beam. The diameter and depth of the distorted zone increase as the Laser power and irradiation time increase. The depth grows exponentially depending on the irradiation time. The maximum residual stress discrepancy is located near the boundary of the Laser affected zone. The Laser Damage resistance test results show that the distorted zone and the Laser affected zone have a better Damage resistance than the original substrate.
Jeanyves Natoli - One of the best experts on this subject based on the ideXlab platform.
-
catastrophic nanosecond Laser induced Damage in the bulk of potassium titanyl phosphate crystals
Journal of Applied Physics, 2014Co-Authors: Frank Wagner, Jeanyves Natoli, Hassan Akhouayri, G Duchateau, Mireille CommandreAbstract:Due to its high effective nonlinearity and the possibility to produce periodically poled crystals, potassium titanyl phosphate (KTiOPO4, KTP) is still one of the economically important nonlinear optical materials. In this overview article, we present a large study on catastrophic nanosecond Laser induced Damage in this material and the very similar RbTiOPO4 (RTP). Several different systematic studies are included: multiple pulse Laser Damage, multi-wavelength Laser Damage in KTP, Damage resistance anisotropy, and variations of the Laser Damage thresholds for RTP crystals of different qualities. All measurements were carried out in comparable experimental conditions using a 1064 nm Q-switched Laser and some were repeated at 532 nm. After summarizing the experimental results, we detail the proposed model for Laser Damage in this material and discuss the experimental results in this context. According to the model, nanosecond Laser Damage is caused by light-induced generation of transient Laser-Damage precursors which subsequently provide free electrons that are heated by the same nanosecond pulse. We also present a stimulated Raman scattering measurement and confront slightly different models to the experimental data. Finally, the physical nature of the transient Damage precursors is discussed and similarities and differences to Laser Damage in other crystals are pointed out.
-
catastrophic nanosecond Laser induced Damage in the bulk of potassium titanyl phosphate crystals
Journal of Applied Physics, 2014Co-Authors: Frank Wagner, Jeanyves Natoli, Hassan Akhouayri, G Duchateau, Mireille CommandreAbstract:Due to its high effective nonlinearity and the possibility to produce periodically poled crystals, potassium titanyl phosphate (KTiOPO4, KTP) is still one of the economically important nonlinear optical materials. In this overview article, we present a large study on catastrophic nanosecond Laser induced Damage in this material and the very similar RbTiOPO4 (RTP). Several different systematic studies are included: multiple pulse Laser Damage, multi-wavelength Laser Damage in KTP, Damage resistance anisotropy, and variations of the Laser Damage thresholds for RTP crystals of different qualities. All measurements were carried out in comparable experimental conditions using a 1064 nm Q-switched Laser and some were repeated at 532 nm. After summarizing the experimental results, we detail the proposed model for Laser Damage in this material and discuss the experimental results in this context. According to the model, nanosecond Laser Damage is caused by light-induced generation of transient Laser-Damage precur...
-
multipulse Laser Damage in potassium titanyl phosphate statistical interpretation of measurements and the Damage initiation mechanism
Optical Engineering, 2012Co-Authors: Frank R Wagner, Laurent Gallais, Mireille Commandre, Anne Hildenbrand, Hassan Akhouayri, Celine Gouldieff, Jeanyves NatoliAbstract:Multipulse Laser-induced Damage is an important topic for many applications of nonlinear crystals. We studied multipulse Damage in X-cut KTiOPO4. Using a 6-ns Nd:YAG Laser with a weakly focused beam, a fatigue phenomenon was observed. We addressed whether this phenomenon necessarily implies material modifications. Two possible models were tested, both of them predicting increasing Damage probability with increasing pulse number while all material properties are kept constant. The first model, pulse energy fluctuations and depointing, increases the probed volume during multiple pulse experiments. The probability to cause Damage thus increases with increasing pulse number; however, this effect is too small to explain the observed fatigue. The second model assumes a constant single-shot Damage probability p1, so a multipulse experiment can be described by statistically independent resampling of the material. Very good agreement was found between the 2000-on-1 volume Damage data and this statistical multipulse model. Additionally, the spot size dependency of the Damage probability is well described by a precursor presence model. Supposing that Laser Damage precursors are transient, the presented data explain the experimental results without supposing material modifications.
-
investigation of nanodefect properties in optical coatings by coupling measured and simulated Laser Damage statistics
Journal of Applied Physics, 2008Co-Authors: Laurent Gallais, Jérémie Capoulade, Jeanyves Natoli, Mireille CommandreAbstract:We propose a model to link Laser Damage initiator properties (such as nature, size distribution, and density) to measured Laser Damage probabilities in optical materials. The model is based on the calculation of light absorption in nanoabsorbers and subsequent heating, coupled to Laser Damage statistics, and allows to obtain the Laser Damage probability as a function of Laser fluence. Applications to the case of optical coatings irradiated in the nanosecond regime are presented. Laser Damage probability curves are measured in hafnia single layer coatings made under different conditions: electron beam deposition and reactive low voltage ion plating. By studying the influence of the Laser irradiation parameters (wavelength and beam size) and coating properties on the simulations, we show with our methodology that initiating defects (hafnium inclusions) can be identified. The implications of this approach for physical understanding and metrology applications are discussed.
-
Laser Damage resistance of hafnia thin films deposited by electron beam deposition, reactive low voltage ion plating, and dual ion beam sputtering.
Applied optics, 2008Co-Authors: Laurent Gallais, Jérémie Capoulade, Cian Koc, Jeanyves Natoli, Mireille Commandre, Michel Cathelinaud, Michel LequimeAbstract:A comparative study is made of the Laser Damage resistance of hafnia coatings deposited on fused silica substrates with different technologies: electron beam deposition (from Hf or HfO(2) starting material), reactive low voltage ion plating, and dual ion beam sputtering. The Laser Damage thresholds of these coatings are determined at 1064 and 355 nm using a nanosecond pulsed YAG Laser and a one-on-one test procedure. The results are associated with a complete characterization of the samples: refractive index n measured by spectrophotometry, extinction coefficient k measured by photothermal deflection, and roughness measured by atomic force microscopy.
Frank Wagner - One of the best experts on this subject based on the ideXlab platform.
-
catastrophic nanosecond Laser induced Damage in the bulk of potassium titanyl phosphate crystals
Journal of Applied Physics, 2014Co-Authors: Frank Wagner, Jeanyves Natoli, Hassan Akhouayri, G Duchateau, Mireille CommandreAbstract:Due to its high effective nonlinearity and the possibility to produce periodically poled crystals, potassium titanyl phosphate (KTiOPO4, KTP) is still one of the economically important nonlinear optical materials. In this overview article, we present a large study on catastrophic nanosecond Laser induced Damage in this material and the very similar RbTiOPO4 (RTP). Several different systematic studies are included: multiple pulse Laser Damage, multi-wavelength Laser Damage in KTP, Damage resistance anisotropy, and variations of the Laser Damage thresholds for RTP crystals of different qualities. All measurements were carried out in comparable experimental conditions using a 1064 nm Q-switched Laser and some were repeated at 532 nm. After summarizing the experimental results, we detail the proposed model for Laser Damage in this material and discuss the experimental results in this context. According to the model, nanosecond Laser Damage is caused by light-induced generation of transient Laser-Damage precur...
-
catastrophic nanosecond Laser induced Damage in the bulk of potassium titanyl phosphate crystals
Journal of Applied Physics, 2014Co-Authors: Frank Wagner, Jeanyves Natoli, Hassan Akhouayri, G Duchateau, Mireille CommandreAbstract:Due to its high effective nonlinearity and the possibility to produce periodically poled crystals, potassium titanyl phosphate (KTiOPO4, KTP) is still one of the economically important nonlinear optical materials. In this overview article, we present a large study on catastrophic nanosecond Laser induced Damage in this material and the very similar RbTiOPO4 (RTP). Several different systematic studies are included: multiple pulse Laser Damage, multi-wavelength Laser Damage in KTP, Damage resistance anisotropy, and variations of the Laser Damage thresholds for RTP crystals of different qualities. All measurements were carried out in comparable experimental conditions using a 1064 nm Q-switched Laser and some were repeated at 532 nm. After summarizing the experimental results, we detail the proposed model for Laser Damage in this material and discuss the experimental results in this context. According to the model, nanosecond Laser Damage is caused by light-induced generation of transient Laser-Damage precursors which subsequently provide free electrons that are heated by the same nanosecond pulse. We also present a stimulated Raman scattering measurement and confront slightly different models to the experimental data. Finally, the physical nature of the transient Damage precursors is discussed and similarities and differences to Laser Damage in other crystals are pointed out.
Hassan Akhouayri - One of the best experts on this subject based on the ideXlab platform.
-
catastrophic nanosecond Laser induced Damage in the bulk of potassium titanyl phosphate crystals
Journal of Applied Physics, 2014Co-Authors: Frank Wagner, Jeanyves Natoli, Hassan Akhouayri, G Duchateau, Mireille CommandreAbstract:Due to its high effective nonlinearity and the possibility to produce periodically poled crystals, potassium titanyl phosphate (KTiOPO4, KTP) is still one of the economically important nonlinear optical materials. In this overview article, we present a large study on catastrophic nanosecond Laser induced Damage in this material and the very similar RbTiOPO4 (RTP). Several different systematic studies are included: multiple pulse Laser Damage, multi-wavelength Laser Damage in KTP, Damage resistance anisotropy, and variations of the Laser Damage thresholds for RTP crystals of different qualities. All measurements were carried out in comparable experimental conditions using a 1064 nm Q-switched Laser and some were repeated at 532 nm. After summarizing the experimental results, we detail the proposed model for Laser Damage in this material and discuss the experimental results in this context. According to the model, nanosecond Laser Damage is caused by light-induced generation of transient Laser-Damage precur...
-
catastrophic nanosecond Laser induced Damage in the bulk of potassium titanyl phosphate crystals
Journal of Applied Physics, 2014Co-Authors: Frank Wagner, Jeanyves Natoli, Hassan Akhouayri, G Duchateau, Mireille CommandreAbstract:Due to its high effective nonlinearity and the possibility to produce periodically poled crystals, potassium titanyl phosphate (KTiOPO4, KTP) is still one of the economically important nonlinear optical materials. In this overview article, we present a large study on catastrophic nanosecond Laser induced Damage in this material and the very similar RbTiOPO4 (RTP). Several different systematic studies are included: multiple pulse Laser Damage, multi-wavelength Laser Damage in KTP, Damage resistance anisotropy, and variations of the Laser Damage thresholds for RTP crystals of different qualities. All measurements were carried out in comparable experimental conditions using a 1064 nm Q-switched Laser and some were repeated at 532 nm. After summarizing the experimental results, we detail the proposed model for Laser Damage in this material and discuss the experimental results in this context. According to the model, nanosecond Laser Damage is caused by light-induced generation of transient Laser-Damage precursors which subsequently provide free electrons that are heated by the same nanosecond pulse. We also present a stimulated Raman scattering measurement and confront slightly different models to the experimental data. Finally, the physical nature of the transient Damage precursors is discussed and similarities and differences to Laser Damage in other crystals are pointed out.
-
multipulse Laser Damage in potassium titanyl phosphate statistical interpretation of measurements and the Damage initiation mechanism
Optical Engineering, 2012Co-Authors: Frank R Wagner, Laurent Gallais, Mireille Commandre, Anne Hildenbrand, Hassan Akhouayri, Celine Gouldieff, Jeanyves NatoliAbstract:Multipulse Laser-induced Damage is an important topic for many applications of nonlinear crystals. We studied multipulse Damage in X-cut KTiOPO4. Using a 6-ns Nd:YAG Laser with a weakly focused beam, a fatigue phenomenon was observed. We addressed whether this phenomenon necessarily implies material modifications. Two possible models were tested, both of them predicting increasing Damage probability with increasing pulse number while all material properties are kept constant. The first model, pulse energy fluctuations and depointing, increases the probed volume during multiple pulse experiments. The probability to cause Damage thus increases with increasing pulse number; however, this effect is too small to explain the observed fatigue. The second model assumes a constant single-shot Damage probability p1, so a multipulse experiment can be described by statistically independent resampling of the material. Very good agreement was found between the 2000-on-1 volume Damage data and this statistical multipulse model. Additionally, the spot size dependency of the Damage probability is well described by a precursor presence model. Supposing that Laser Damage precursors are transient, the presented data explain the experimental results without supposing material modifications.
