Optics are not keeping up with the pace of laser advancements. The laser industry is rapidly increasing its power capabilities and reducing wavelengths which have exposed the optics as a weak link in lifetime failures for these advanced systems. Nanometer sized surface defects (scratches, pits, bumps and residual particles) on the surface of optics are a significant limiting factor to high end performance. Angstrom level smoothing of materials such as calcium fluoride, spinel, magnesium fluoride, zinc sulfide, LBO and others presents a unique challenge for traditional polishing techniques. Exogenesis Corporation, using its new and proprietary Accelerated Neutral Atom Beam (ANAB) technology, is able to remove nano-scale surface damage and particle contamination leaving many material surfaces with roughness typically around one Angstrom. This surface defect mitigation via ANAB processing can be shown to increase performance properties of high intensity optical materials. This paper describes the ANAB technology and summarizes smoothing results for calcium fluoride laser windows. It further correlates laser damage threshold improvements with the smoothing produced by ANAB surface treatment. All ANAB processing was performed at Exogenesis Corporation using an nAccel100TM Accelerated Particle Beam processing tool. All surface measurement data for the paper was produced via AFM analysis on a Park Model XE70 AFM, and all laser damage testing was performed at Spica Technologies, Inc. Exogenesis Corporation’s ANAB processing technology is a new and unique surface modification technique that has demonstrated to be highly effective at correcting nano-scale surface defects. ANAB is a non-contact vacuum process comprised of an intense beam of accelerated, electrically neutral gas atoms with average energies of a few tens of electron volts. The ANAB process does not apply mechanical forces associated with traditional polishing techniques. ANAB efficiently removes surface contaminants, nano-scale scratches, bumps, particles and other asperities under low energy physical sputtering conditions. ANAB may be used to remove a precisely controlled, uniform thickness of material without any increase of surface roughness, regardless of the total amount of material removed. The ANAB process does not involve the use of slurries or other abrasive polishing compounds and therefore does not require any post process cleaning. ANAB can be integrated as an in-situ surface preparation method for other process steps in the uninterrupted fabrication of optical devices.
{"title":"Improved laser damage threshold performance of calcium fluoride optical surfaces via Accelerated Neutral Atom Beam (ANAB) processing","authors":"S. Kirkpatrick, M. Walsh, R. Svrluga, M. Thomas","doi":"10.1117/12.2196545","DOIUrl":"https://doi.org/10.1117/12.2196545","url":null,"abstract":"Optics are not keeping up with the pace of laser advancements. The laser industry is rapidly increasing its power capabilities and reducing wavelengths which have exposed the optics as a weak link in lifetime failures for these advanced systems. Nanometer sized surface defects (scratches, pits, bumps and residual particles) on the surface of optics are a significant limiting factor to high end performance. Angstrom level smoothing of materials such as calcium fluoride, spinel, magnesium fluoride, zinc sulfide, LBO and others presents a unique challenge for traditional polishing techniques. Exogenesis Corporation, using its new and proprietary Accelerated Neutral Atom Beam (ANAB) technology, is able to remove nano-scale surface damage and particle contamination leaving many material surfaces with roughness typically around one Angstrom. This surface defect mitigation via ANAB processing can be shown to increase performance properties of high intensity optical materials. This paper describes the ANAB technology and summarizes smoothing results for calcium fluoride laser windows. It further correlates laser damage threshold improvements with the smoothing produced by ANAB surface treatment. All ANAB processing was performed at Exogenesis Corporation using an nAccel100TM Accelerated Particle Beam processing tool. All surface measurement data for the paper was produced via AFM analysis on a Park Model XE70 AFM, and all laser damage testing was performed at Spica Technologies, Inc. Exogenesis Corporation’s ANAB processing technology is a new and unique surface modification technique that has demonstrated to be highly effective at correcting nano-scale surface defects. ANAB is a non-contact vacuum process comprised of an intense beam of accelerated, electrically neutral gas atoms with average energies of a few tens of electron volts. The ANAB process does not apply mechanical forces associated with traditional polishing techniques. ANAB efficiently removes surface contaminants, nano-scale scratches, bumps, particles and other asperities under low energy physical sputtering conditions. ANAB may be used to remove a precisely controlled, uniform thickness of material without any increase of surface roughness, regardless of the total amount of material removed. The ANAB process does not involve the use of slurries or other abrasive polishing compounds and therefore does not require any post process cleaning. ANAB can be integrated as an in-situ surface preparation method for other process steps in the uninterrupted fabrication of optical devices.","PeriodicalId":204978,"journal":{"name":"SPIE Laser Damage","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114410286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Demos, R. Negres, R. Raman, M. Feit, K. Manes, A. Rubenchik
Laser induced damage (breakdown) initiated on the exit surface of transparent dielectric materials using nanosecond pulses creates a volume of superheated material reaching localized temperatures on the order of 1 eV and pressures on the order of 10 GPa or larger. This leads to material ejection and the formation of a crater. The volume of this superheated material depends largely on the laser parameters such as fluence and pulse duration. To elucidate the material behaviors involved, we examined the morphologies of the ejected superheated material particles and found distinctive morphologies. We hypothesize that these morphologies arise from the difference in the structure and physical properties (such as the dynamic viscosity and presence of instabilities) of the superheated material at the time of ejection of each individual particle. Some of the ejected particles are on the order of 1 µm in diameter and appear as “droplets”. Another subgroup appears to have stretched, foam-like structure that can be described as material globules interconnected via smaller in diameter columns. Such particles often contain nanometer size fibers attached on their surface. In other cases, only the globules have been preserved suggesting that they may be associated with a collapsed foam structure under the dynamic pressure as it traverses in air. These distinct features originate in the structure of the superheated material during volume boiling just prior to the ejection of the particles.
{"title":"Morphology of ejected debris from laser super-heated fused silica following exit surface laser-induced damage","authors":"S. Demos, R. Negres, R. Raman, M. Feit, K. Manes, A. Rubenchik","doi":"10.1117/12.2195501","DOIUrl":"https://doi.org/10.1117/12.2195501","url":null,"abstract":"Laser induced damage (breakdown) initiated on the exit surface of transparent dielectric materials using nanosecond pulses creates a volume of superheated material reaching localized temperatures on the order of 1 eV and pressures on the order of 10 GPa or larger. This leads to material ejection and the formation of a crater. The volume of this superheated material depends largely on the laser parameters such as fluence and pulse duration. To elucidate the material behaviors involved, we examined the morphologies of the ejected superheated material particles and found distinctive morphologies. We hypothesize that these morphologies arise from the difference in the structure and physical properties (such as the dynamic viscosity and presence of instabilities) of the superheated material at the time of ejection of each individual particle. Some of the ejected particles are on the order of 1 µm in diameter and appear as “droplets”. Another subgroup appears to have stretched, foam-like structure that can be described as material globules interconnected via smaller in diameter columns. Such particles often contain nanometer size fibers attached on their surface. In other cases, only the globules have been preserved suggesting that they may be associated with a collapsed foam structure under the dynamic pressure as it traverses in air. These distinct features originate in the structure of the superheated material during volume boiling just prior to the ejection of the particles.","PeriodicalId":204978,"journal":{"name":"SPIE Laser Damage","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123042470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The concept of a laser damage threshold as a safe operating level is both useful and confounding. This paper examines and analyzes the power of the concept of a laser damage threshold, identifying the good and the danger in its use. The history of the definition and concept of the laser damage threshold is traced from the earliest days of the laser through to the present day. Criteria for an accurate threshold measurement are presented and distribution of the weakest site on an optic is derived to provide a basis of analysis. Using a pedagogically selected defect distribution, the statistics of the weakest site are derived. The dependence of the weakest site on the area of the test is shown explicitly. It is argued that typical small area tests, characteristic of most main stream damage tests have insufficient area to include the true weakest site, and are therefore generally inaccurate. The paper concludes with some ideas on how to redefine the threshold measurement technique resulting in a more accurate test procedure.
{"title":"Laser damage threshold: useful idea or dangerous misconception?","authors":"J. Arenberg","doi":"10.1117/12.2195271","DOIUrl":"https://doi.org/10.1117/12.2195271","url":null,"abstract":"The concept of a laser damage threshold as a safe operating level is both useful and confounding. This paper examines and analyzes the power of the concept of a laser damage threshold, identifying the good and the danger in its use. The history of the definition and concept of the laser damage threshold is traced from the earliest days of the laser through to the present day. Criteria for an accurate threshold measurement are presented and distribution of the weakest site on an optic is derived to provide a basis of analysis. Using a pedagogically selected defect distribution, the statistics of the weakest site are derived. The dependence of the weakest site on the area of the test is shown explicitly. It is argued that typical small area tests, characteristic of most main stream damage tests have insufficient area to include the true weakest site, and are therefore generally inaccurate. The paper concludes with some ideas on how to redefine the threshold measurement technique resulting in a more accurate test procedure.","PeriodicalId":204978,"journal":{"name":"SPIE Laser Damage","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134121639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Ďurák, D. Kramer, P. Velpula, J. Cupal, T. Medřík, J. Hrebicek, J. Golasowski, D. Peceli, L. Fekete, V. Stepan, M. Kozlová, B. Rus
The ELI Beamlines project will deliver ultrafast laser pulses with peak powers up to 10PW available every minute and PW class beams at 10Hz complemented by a 10TW 1kHz beamline. To properly determine damage thresholds of involved optical components in conditions similar to the operational environment and with expected laser parameters, a high vacuum LIDT test station was constructed at PALS facility. Our study presents results of ISO based S-on-1 and R-on-1 tests in femtosecond regime (50fs, 800nm, 10Hz/1kHz) performed on two different types of coatings: a) highabsorption black coatings with low outgassing rates, intended for use as a beam dump surface; and b) high-reflectivity, low-dispersion 45° AOI ultrafast mirror coatings. Testing of absorptive coatings was accompanied with QMS residual gas analysis to verify, that high intensity laser radiation approaching the damage threshold does not increase concentration of volatile organic compounds in the vacuum chamber. In case of HR mirror coatings, we also investigate the effect of cleaning on LIDT value, comparing characteristic S-on-1 curves of given sample with values obtained after 12h immersion in ethanol-water solution.
{"title":"Ultrafast beam dump materials and mirror coatings tested with the ELI beamlines LIDT test station","authors":"M. Ďurák, D. Kramer, P. Velpula, J. Cupal, T. Medřík, J. Hrebicek, J. Golasowski, D. Peceli, L. Fekete, V. Stepan, M. Kozlová, B. Rus","doi":"10.1117/12.2194970","DOIUrl":"https://doi.org/10.1117/12.2194970","url":null,"abstract":"The ELI Beamlines project will deliver ultrafast laser pulses with peak powers up to 10PW available every minute and PW class beams at 10Hz complemented by a 10TW 1kHz beamline. To properly determine damage thresholds of involved optical components in conditions similar to the operational environment and with expected laser parameters, a high vacuum LIDT test station was constructed at PALS facility. Our study presents results of ISO based S-on-1 and R-on-1 tests in femtosecond regime (50fs, 800nm, 10Hz/1kHz) performed on two different types of coatings: a) highabsorption black coatings with low outgassing rates, intended for use as a beam dump surface; and b) high-reflectivity, low-dispersion 45° AOI ultrafast mirror coatings. Testing of absorptive coatings was accompanied with QMS residual gas analysis to verify, that high intensity laser radiation approaching the damage threshold does not increase concentration of volatile organic compounds in the vacuum chamber. In case of HR mirror coatings, we also investigate the effect of cleaning on LIDT value, comparing characteristic S-on-1 curves of given sample with values obtained after 12h immersion in ethanol-water solution.","PeriodicalId":204978,"journal":{"name":"SPIE Laser Damage","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125121192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yejia Xu, A. Khabbazi, T. Day, A. Brown, L. Emmert, J. Talghader, E. Field, D. Kletecka, J. Bellum, D. Patel, C. Menoni, W. Rudolph
The laser damage behavior of high quality coatings under nanosecond pulse illumination is controlled by statistically distributed defects, whose physical nature and defect mechanisms are still largely unknown. Defect densities are often retrieved by modeling the fluence dependence of the damage probability measured by traditional damage test (TDT) methods, based on ‘damage’ or ‘no damage’ observations. STEREO-LID (Spatio-TEmporally REsolved Optical LaserInduced Damage) allows the determination of the damage fluence (and intensity) in a single test by identifying the initiation of damage both temporally and spatially. The advantages of this test method over the TDT are discussed. In particular, its ability to retrieve detailed defect distribution functions is demonstrated by comparison of results from HfO2 films prepared by ion-assisted electron beam evaporation, ion-beam sputtering, and atomic layer deposition.
{"title":"Comparative STEREO-LID (Spatio-TEmporally REsolved Optical Laser-Induced Damage) studies of critical defect distributions in IBS, ALD, and electron-beam coated dielectric films","authors":"Yejia Xu, A. Khabbazi, T. Day, A. Brown, L. Emmert, J. Talghader, E. Field, D. Kletecka, J. Bellum, D. Patel, C. Menoni, W. Rudolph","doi":"10.1117/12.2196548","DOIUrl":"https://doi.org/10.1117/12.2196548","url":null,"abstract":"The laser damage behavior of high quality coatings under nanosecond pulse illumination is controlled by statistically distributed defects, whose physical nature and defect mechanisms are still largely unknown. Defect densities are often retrieved by modeling the fluence dependence of the damage probability measured by traditional damage test (TDT) methods, based on ‘damage’ or ‘no damage’ observations. STEREO-LID (Spatio-TEmporally REsolved Optical LaserInduced Damage) allows the determination of the damage fluence (and intensity) in a single test by identifying the initiation of damage both temporally and spatially. The advantages of this test method over the TDT are discussed. In particular, its ability to retrieve detailed defect distribution functions is demonstrated by comparison of results from HfO2 films prepared by ion-assisted electron beam evaporation, ion-beam sputtering, and atomic layer deposition.","PeriodicalId":204978,"journal":{"name":"SPIE Laser Damage","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115548726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Optical coatings with the highest laser damage thresholds rely on clean conditions in the vacuum chamber during the coating deposition process. A low base pressure in the coating chamber, as well as the ability of the vacuum system to maintain the required pressure during deposition, are important aspects of limiting the amount of defects in an optical coating that could induce laser damage. Our large optics coating chamber at Sandia National Laboratories normally relies on three cryo pumps to maintain low pressures for e-beam coating processes. However, on occasion, one or more of the cryo pumps have been out of commission. In light of this circumstance, we decided to explore how deposition under compromised vacuum conditions resulting from the use of only one or two cryo pumps affects the laser-induced damage thresholds of optical coatings. The coatings of this study consist of HfO2 and SiO2 layer materials and include antireflection coatings for 527 nm at normal incidence, and high reflection coatings for 527 nm, 45° angle of incidence (AOI), in P-polarization (P-pol).
{"title":"How reduced vacuum pumping capability in a coating chamber affects the laser damage resistance of HfO2/SiO2 antireflection and high-reflection coatings","authors":"E. Field, J. Bellum, D. Kletecka","doi":"10.1117/12.2194131","DOIUrl":"https://doi.org/10.1117/12.2194131","url":null,"abstract":"Optical coatings with the highest laser damage thresholds rely on clean conditions in the vacuum chamber during the coating deposition process. A low base pressure in the coating chamber, as well as the ability of the vacuum system to maintain the required pressure during deposition, are important aspects of limiting the amount of defects in an optical coating that could induce laser damage. Our large optics coating chamber at Sandia National Laboratories normally relies on three cryo pumps to maintain low pressures for e-beam coating processes. However, on occasion, one or more of the cryo pumps have been out of commission. In light of this circumstance, we decided to explore how deposition under compromised vacuum conditions resulting from the use of only one or two cryo pumps affects the laser-induced damage thresholds of optical coatings. The coatings of this study consist of HfO2 and SiO2 layer materials and include antireflection coatings for 527 nm at normal incidence, and high reflection coatings for 527 nm, 45° angle of incidence (AOI), in P-polarization (P-pol).","PeriodicalId":204978,"journal":{"name":"SPIE Laser Damage","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115571493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chinmayee V Prabhu Dessai, I. Reddy, S. Parne, G. R. Reddy
Tunable LASER source is a device which emits a particular light wavelength based on the tuning done. The tuning depends on certain characteristic of the LASER source which makes it customised within a gamut of wavelengths. Most Conventional LASER sources in the market are bulky and complex. The Tunable LASER source designed is established on the simple idea that Optical Amplifier can act as a broadband source, and temperature and strain sensitive Fiber Bragg Grating can be used to filter the required wavelength. This makes the design very light and elementary.
{"title":"Tunable laser source based on storage device using Bragg grating","authors":"Chinmayee V Prabhu Dessai, I. Reddy, S. Parne, G. R. Reddy","doi":"10.1117/12.2197183","DOIUrl":"https://doi.org/10.1117/12.2197183","url":null,"abstract":"Tunable LASER source is a device which emits a particular light wavelength based on the tuning done. The tuning depends on certain characteristic of the LASER source which makes it customised within a gamut of wavelengths. Most Conventional LASER sources in the market are bulky and complex. The Tunable LASER source designed is established on the simple idea that Optical Amplifier can act as a broadband source, and temperature and strain sensitive Fiber Bragg Grating can be used to filter the required wavelength. This makes the design very light and elementary.","PeriodicalId":204978,"journal":{"name":"SPIE Laser Damage","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123103325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Diaz, M. Chambonneau, P. Grua, J. Rullier, J. Natoli, L. Lamaignère
The influence of vacuum on nanosecond laser-induced damage at the exit surface of fused silica components is investigated at 1064 nm. In the present study, as previously observed in air, ring patterns surrounding laserinduced damage sites are systematically observed on a plane surface when initiated by multiple longitudinal modes laser pulses. Compared to air, the printed pattern is clearly more concentrated. The obtained correlation between the damage morphology and the temporal structure of the pulses suggests a laser-driven ablation mechanism resulting in a thorough imprint of energy deposit. The ablation process is assumed to be subsequent to an activation of the surface by hot electrons related to the diffusive expansion of a plasma formed from silica. This interpretation is strongly reinforced with additional experiments performed on an optical grating in vacuum on which damage sites do not show any ring pattern. Qualitatively, in vacuum, the intensity-dependent ring appearance speed V ∝ I1/2 is shown to be different than in air where V ∝ I1/3 . This demonstrates that the mechanisms of formation of ring patterns are different in vacuum than in air. Moreover, the mechanism responsible of the propagation of the activation front in vacuum is shown to be outdone when experiments are performed in air.
{"title":"Study of laser-induced damage at 1064nm in fused silica samples in vacuum environment","authors":"R. Diaz, M. Chambonneau, P. Grua, J. Rullier, J. Natoli, L. Lamaignère","doi":"10.1117/12.2195471","DOIUrl":"https://doi.org/10.1117/12.2195471","url":null,"abstract":"The influence of vacuum on nanosecond laser-induced damage at the exit surface of fused silica components is investigated at 1064 nm. In the present study, as previously observed in air, ring patterns surrounding laserinduced damage sites are systematically observed on a plane surface when initiated by multiple longitudinal modes laser pulses. Compared to air, the printed pattern is clearly more concentrated. The obtained correlation between the damage morphology and the temporal structure of the pulses suggests a laser-driven ablation mechanism resulting in a thorough imprint of energy deposit. The ablation process is assumed to be subsequent to an activation of the surface by hot electrons related to the diffusive expansion of a plasma formed from silica. This interpretation is strongly reinforced with additional experiments performed on an optical grating in vacuum on which damage sites do not show any ring pattern. Qualitatively, in vacuum, the intensity-dependent ring appearance speed V ∝ I1/2 is shown to be different than in air where V ∝ I1/3 . This demonstrates that the mechanisms of formation of ring patterns are different in vacuum than in air. Moreover, the mechanism responsible of the propagation of the activation front in vacuum is shown to be outdone when experiments are performed in air.","PeriodicalId":204978,"journal":{"name":"SPIE Laser Damage","volume":"9632 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130902901","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A combined cavity ring-down (CRD) and photometry technique is employed to measure the transmittance of optical laser components in a range extending from below 0.01% to over 99.99%. In this combined technique, the conventional photometric configuration is used to measure, by ratioing the transmitted light power to the input power, the transmittance ranging from below 0.01% to over 99% with a typical relative uncertainty below 0.3%, and the CRD configuration is used to measure the transmittance higher than 99% with an uncertainty below 0.01%. Eight test samples with transmittance in the range of nearly 99.99% to approximately 0.013% are experimentally measured. Uncertainties of approximately 0.0001% for the transmittance of 99.9877% and of 0.003% for the transmittance of 0.013% are achieved with respectively the CRD and photometric schemes of a simple experimental apparatus. The experimental results showed that the combined technique is capable of measuring the transmittance of any practically fabricated optical laser components.
{"title":"Transmittance measurements of laser components using a combination of cavity ring-down and photometry","authors":"H. Cui, Y. Han, C. Gao, Y. Wang, B. Li","doi":"10.1117/12.2197779","DOIUrl":"https://doi.org/10.1117/12.2197779","url":null,"abstract":"A combined cavity ring-down (CRD) and photometry technique is employed to measure the transmittance of optical laser components in a range extending from below 0.01% to over 99.99%. In this combined technique, the conventional photometric configuration is used to measure, by ratioing the transmitted light power to the input power, the transmittance ranging from below 0.01% to over 99% with a typical relative uncertainty below 0.3%, and the CRD configuration is used to measure the transmittance higher than 99% with an uncertainty below 0.01%. Eight test samples with transmittance in the range of nearly 99.99% to approximately 0.013% are experimentally measured. Uncertainties of approximately 0.0001% for the transmittance of 99.9877% and of 0.003% for the transmittance of 0.013% are achieved with respectively the CRD and photometric schemes of a simple experimental apparatus. The experimental results showed that the combined technique is capable of measuring the transmittance of any practically fabricated optical laser components.","PeriodicalId":204978,"journal":{"name":"SPIE Laser Damage","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130945358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Ly, T. Laurence, N. Shen, B. Hollingsworth, M. Norton, J. Bude
We investigate the multipulse degradation of fused silica surfaces exposed at 351 nm for up to 109 pulses at pulse fluences greater than 10 J/cm2. In vacuum, the transmission loss increases as a function of the number of shots at low pulse intensity. However, as the pulse intensity increases, the transmission loss decreases and is not measureable above a certain intensity. Transmission loss is highest when measured at shorter wavelengths, and decreases towards the IR. Absorption is the primary mechanism that leads to transmission loss and is from photo-reduction of the silica surface.
{"title":"Multipulse degradation of fused silica surfaces at 351 nm","authors":"S. Ly, T. Laurence, N. Shen, B. Hollingsworth, M. Norton, J. Bude","doi":"10.1117/12.2195595","DOIUrl":"https://doi.org/10.1117/12.2195595","url":null,"abstract":"We investigate the multipulse degradation of fused silica surfaces exposed at 351 nm for up to 109 pulses at pulse fluences greater than 10 J/cm2. In vacuum, the transmission loss increases as a function of the number of shots at low pulse intensity. However, as the pulse intensity increases, the transmission loss decreases and is not measureable above a certain intensity. Transmission loss is highest when measured at shorter wavelengths, and decreases towards the IR. Absorption is the primary mechanism that leads to transmission loss and is from photo-reduction of the silica surface.","PeriodicalId":204978,"journal":{"name":"SPIE Laser Damage","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131784916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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