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Time Resolved Imaging Of Material Response During Laser Induced Bulk Damage In Sio2
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Book Synopsis Time-resolved Imaging of Material Response During Laser-induced Bulk Damage in SiO2 by :
Download or read book Time-resolved Imaging of Material Response During Laser-induced Bulk Damage in SiO2 written by and published by . This book was released on 2008 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: We report on time resolved imaging of the dynamic events taking place during laser-induced damage in the bulk of fused silica samples with nanosecond temporal resolution and one micron spatial resolution. These events include: shock/pressure wave formation and propagation, transient absorption, crack propagation and formation of residual stress fields. The work has been performed using a time-resolved microscope system that utilizes a probe pulse to acquire images at delay times covering the entire timeline of a damage event. Image information is enhanced using polarized illumination and simultaneously recording the two orthogonal polarization image components. For the case of fused silica, an electronic excitation is first observed accompanied by the onset of a pressure wave generation and propagation. Cracks are seen to form early in the process and reach their final size at about 25 ns into the damage event. In addition, changes that in part are attributed to transient absorption in the modified material are observed for delays up to about 200 microseconds.
Book Synopsis Time-Resolved Imaging of Material Response Following Laser-Induced Breakdown in the Bulk and Surface of Fused Silica by :
Download or read book Time-Resolved Imaging of Material Response Following Laser-Induced Breakdown in the Bulk and Surface of Fused Silica written by and published by . This book was released on 2010 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Optical components within high energy laser systems are susceptible to laser-induced material modification when the breakdown threshold is exceeded or damage is initiated by pre-existing impurities or defects. These modifications are the result of exposure to extreme conditions involving the generation of high temperatures and pressures and occur on a volumetric scale of the order of a few cubic microns. The response of the material following localized energy deposition, including the timeline of events and the individual processes involved during this timeline, is still largely unknown. In this work, we investigate the events taking place during the entire timeline in both bulk and surface damage in fused silica using a set of time-resolved microscopy systems. These microscope systems offer up to 1 micron spatial resolution when imaging static or dynamic effects, allowing for imaging of the entire process with adequate temporal and spatial resolution. These systems incorporate various pump-probe geometries designed to optimize the sensitivity for detecting individual aspects of the process such as the propagation of shock waves, near-surface material motion, the speed of ejecta, and material transformations. The experimental results indicate that the material response can be separated into distinct phases, some terminating within a few tens of nanoseconds but some extending up to about 100 microseconds. Overall the results demonstrate that the final characteristics of the modified region depend on the material response to the energy deposition and not on the laser parameters.
Book Synopsis Laser Induced Damage in Optical Materials by :
Download or read book Laser Induced Damage in Optical Materials written by and published by . This book was released on 1972 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Imaging System to Measure Kinetics of Material Cluster Ejection During Exit-Surface Damage Initiation and Growth in Fused Silica by :
Download or read book Imaging System to Measure Kinetics of Material Cluster Ejection During Exit-Surface Damage Initiation and Growth in Fused Silica written by and published by . This book was released on 2009 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-induced damage on the surface of optical components typically is manifested by the formation of microscopic craters that can ultimately degrade the optics performance characteristics. It is believed that the damage process is the result of the material exposure to high temperatures and pressures within a volume on the order of several cubic microns located just below the surface. The response of the material following initial localized energy deposition by the laser pulse, including the timeline of events and the individual processes involved during this timeline, is still largely unknown. In this work we introduce a time-resolved microscope system designed to enable a detailed investigation of the sequence of dynamic events involved during surface damage. To best capture individual aspects of the damage timeline, this system is employed in multiple imaging configurations (such as multi-view image acquisition at a single time point and multi-image acquisition at different time points of the same event) and offers sensitivity to phenomena at very early delay times. The capabilities of this system are demonstrated with preliminary results from the study of exit-surface damage in fused silica. The time-resolved images provide information on the material response immediately following laser energy deposition, the processes later involved during crater formation or growth, the material ejecta kinetics, and overall material motion and transformation. Such results offer insight into the mechanisms governing damage initiation and growth in the optical components of ICF class laser systems.
Book Synopsis Laser Induced Damage in Optical Materials, 1975 by : Alexander J. Glass
Download or read book Laser Induced Damage in Optical Materials, 1975 written by Alexander J. Glass and published by . This book was released on 1976 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Laser Induced Bulk Damage in SiO2 at 1.064, 0.532 and 0.355 ?m by : M. Bass
Download or read book Laser Induced Bulk Damage in SiO2 at 1.064, 0.532 and 0.355 ?m written by M. Bass and published by . This book was released on 1985 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper we present bulk damage measurements of crystalline quartz and fused silica under single and multiple pulse irradiation where the wavelength was extended to 0.355 ?m. In previous work under irradiation at 1.06 and 0.532 ?m, it was shown that whereas the single pulse damage varies little with material or wavelength, the multiple pulse damage depended strongly on both. Also, in the case of multiple pulse damage the distribution of the number of pulses needed to produce damage as a function of intensity is indicative of an accumulation process.
Book Synopsis Advanced Material Science And Engineering - Proceedings Of The 2016 International Conference (Amse2016) by : Dahai Ren
Download or read book Advanced Material Science And Engineering - Proceedings Of The 2016 International Conference (Amse2016) written by Dahai Ren and published by World Scientific. This book was released on 2016-05-24 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book provides a comprehensive overview of the authors' works which include significant discoveries and pioneering contributions on Materials Process Engineering, Materials Physics and Chemistry, Emerging Areas of Materials Science, and so on. AMSE2016 is an influential international conference for its strong organization team, dependable reputation and a wide range of sponsors from all over the world.
Book Synopsis Effects of Radiation Induced Defects on Laser-Induced Breakdown in SiO2 by : E. Canto
Download or read book Effects of Radiation Induced Defects on Laser-Induced Breakdown in SiO2 written by E. Canto and published by . This book was released on 1988 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of radiation damage on bulk laser-induced breakdown in SiO2 were investigated. Samples studied included Spectrasil A, B, and WF (water free). Measurements of laser-induced breakdown were conducted with 532 and 1064 nm laser pulses of approximately 20 nsec duration. Reductions of up to 40% in the laser-induced breakdown threshold were observed at 532 nm for samples exposed to 108 rads of ?-radiation. The decrease in breakdown threshold for irradiated SiO2 samples at 532 nm was found to be proportional to the linear absorption of the specimen at 266 nm. These results are in good agreement with a proposed model which suggests that two-photon absorption initiated avalanche process is responsible for laser-induced breakdown for these materials.
Book Synopsis 1.06 ?m Laser-Induced Breakdown of CO2-Laser-Polished Fused SiO2 by : PA. Temple
Download or read book 1.06 ?m Laser-Induced Breakdown of CO2-Laser-Polished Fused SiO2 written by PA. Temple and published by . This book was released on 1981 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fused silica surfaces have been treated with continuous wave CO2-laser radiation in an improved raster technique. Laser damage data for 1.06-?m, 9-nsec, small-spot irradiation are presented. It is shown that a reasonably sharp transition from laser damage prone to laser damage resistant surfaces takes place over a small CO2-laser power range. The transition to high damage resistance takes place at a silica surface temperature where material flow begins to take place, as evidenced by the onset of residual strain in the CO2-processed part. These data are taken as evidence that microcrack healing is an important mechanism in increased damage resistance in CO2-polished parts. Also presented are data which show that CO2-treated surfaces have a small-spot damage threshold at least as high as the bulk damage threshold of SiO2. In addition, these treated parts show no obvious change in surface appearance, as seen in total internal reflection microscopy. They also show little change in transmissive figure. It is suggested that uniform preheating be used to eliminate the strain presently seen in CO2-treated parts.
Book Synopsis Laser induced damage in optical materials: 1982 by :
Download or read book Laser induced damage in optical materials: 1982 written by and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Investigate Laser Induced Damage in Optical Coatings Using Time Resolved Raman Spectroscopy by : G. J. Exarhos
Download or read book Investigate Laser Induced Damage in Optical Coatings Using Time Resolved Raman Spectroscopy written by G. J. Exarhos and published by . This book was released on 1985 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: Raman spectroscopy is shown to be a viable and rapid technique for characterization of laser induced damage in thin dielectric coatings of fused silica substrates. Unequivocal identification of crystalline and amorphous phases can be discerned from measured vibrational spectra. A two laser (damage-probe) technique has been developed for in situ analysis of laser coatings. Raman measurements made at long times following pulsed laser damage serve to characterize the equilibrium damage state and can be used to spatially profile the damage zone. Time resolved measurements acquired within nanoseconds following laser induced damage to optical coatings are studied by these and related Raman experiments from which mechanistic information can also be inferred. The primary mechanism of failure in titanium dioxide (TiO2) coatings results from crystalline phase changes induced thermally or by multiphoton excitation processes. A similiar failure mode is predicted for other oxidic coatings such as zirconium dioxide (ZrO2) which can exist in different room temperature stable phases. Keywords: Laser Damage Mechanisms; Time Resolved Raman Spectroscopy; Molecular Vibrational Studies; Laser Heating; Phase Transformations; Titanium Dioxide Optical Coatings.
Book Synopsis Imaging the Early Material Response Associated with Exit Surface Damage in Fused Silica by :
Download or read book Imaging the Early Material Response Associated with Exit Surface Damage in Fused Silica written by and published by . This book was released on 2010 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The processes involved at the onset of damage initiation on the surface of fused silica have been a topic of extensive discussion and thought for more than four decades. Limited experimental results have helped develop models covering specific aspects of the process. In this work we present the results of an experimental study aiming at imaging the material response from the onset of the observation of material modification during exposure to the laser pulse through the time point at which material ejection begins. The system involves damage initiation using a 355 nm pulse, 7.8 ns FWHM in duration and imaging of the affected material volume with spatial resolution on the order of 1 [mu]m using as strobe light a 150 ps laser pulse that is appropriately timed with respect to the pump pulse. The observations reveal that the onset of material modification is associated with regions of increased absorption, i.e., formation of an electronic excitation, leading to a reduction in the probe transmission to only a few percent within a time interval of about 1 ns. This area is subsequently rapidly expanding with a speed of about 1.2 [mu]m/ns and is accompanied by the formation and propagation of radial cracks. These cracks appear to initiate about 2 ns after the start of the expansion of the modified region. The damage sites continue to grow for about 25 ns but the mechanism of expansion after the termination of the laser pulse is via formation and propagation of lateral cracks. During this time, the affected area of the surface appears to expand forming a bulge of about 40 [mu]m in height. The first clear observation of material cluster ejection is noted at about 50 ns delay.
Book Synopsis Using Shaped Pulses to Probe Energy Deposition During Laser-induced Damage of SiO2 Surfaces by :
Download or read book Using Shaped Pulses to Probe Energy Deposition During Laser-induced Damage of SiO2 Surfaces written by and published by . This book was released on 2008 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Laser-induced damage initiation in silica has been shown to follow a power-law behavior with respect to pulse-length. Models based on thermal diffusion physics can successfully predict this scaling and the effect of pulse shape for pulses between about 3ns and 10ns. In this work we use sophisticated new measurement techniques and novel pulse shape experiments to test the limits of this scaling. We show that simple pulse length scaling fails for pulses below about 3ns. Furthermore, double pulse initiation experiments suggest that energy absorbed by the first pulse is lost on time scales much shorter than would be predicted for thermal diffusion. This time scale for energy loss can be strongly modulated by maintaining a small but non-zero intensity between the pulses. By producing damage with various pulse shapes and pulse trains it is demonstrated that the properties of any hypothetical thermal absorber become highly constrained.
Book Synopsis Time-resolved Imaging of Laser-induced Phase Transitions in Free Silver Nanoclusters by : Simon Dold
Download or read book Time-resolved Imaging of Laser-induced Phase Transitions in Free Silver Nanoclusters written by Simon Dold and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Growth of Laser-induced Damage During Repetitive Illumination of HfO2-SiO2 Multilayer Mirror and Polarizer Coatings by :
Download or read book Growth of Laser-induced Damage During Repetitive Illumination of HfO2-SiO2 Multilayer Mirror and Polarizer Coatings written by and published by . This book was released on 1997 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: As peak fluence of high power lasers is increased, it becomes necessary to tolerate damage on mirrors, polarizers. To study how different types of damage morphologies initiate and grow during repetitive illumination, hafnia-silica multilayer mirror and polarizer coatings were laser damage tested. The coatings were prepared by e-beam evaporation and irradiated with a 3-ns pulse at 1064 nm. The damage morphology was recorded after each shot to determine the types of damage that cause massive unstable failure and lower the optic's functional damage threshold. Results were summarized on damage stability maps plotting the average damage size vs number of shots for fluences ranging from 10 to 40 J/cm2. The maps indicate that the commonly observed damage morphologies (pits, flat bottom pits, scalds, outer layer delamination) have distinct growth behaviors and influence the value of the functional damage threshold differently. While pits are stable up to fluences as high as 40 J/cm2, flat bottom pits can grow during repetitive illumination above a critical fluence of about 35 J/cm2. Scalds are formed in the first shot and never grow at fluences below 40 J/cm2. Finally, delaminates are highly unstable and have the potential for damaging the coating catastrophically above 15 J/cm2. Results show that delaminate damage should be prevented; this knowledge has allowed coatings development efforts to focus on eliminating the origin of such damage morphology.
Download or read book Optics Letters written by and published by . This book was released on 1999 with total page 738 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Time-resolved Laser Induced Breakdown Spectroscopy of Al-Mg Alloys by : M. Sabsabi
Download or read book Time-resolved Laser Induced Breakdown Spectroscopy of Al-Mg Alloys written by M. Sabsabi and published by . This book was released on 1993 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
