scholarly journals Impact of the Polishing Suspension Concentration on Laser Damage of Classically Manufactured and Plasma Post-Processed Zinc Crown Glass Surfaces

2018 ◽  
Vol 8 (9) ◽  
pp. 1556 ◽  
Author(s):  
Christoph Gerhard ◽  
Marco Stappenbeck
Keyword(s):  
Damage Threshold ◽  
Surface Contamination ◽  
Laser Damage ◽  
Surface Finishing ◽  
Process Conditions ◽  
Post Processing ◽  
Suspension Concentration ◽  
Laser Induced Damage ◽  
Glass Surfaces ◽  
The Impact

The laser-induced damage threshold of optics is an issue of essential importance in high-power laser applications. However, the complex and partially interacting mechanisms as well as the underlying reasons for laser damage of glass surfaces are not yet fully understood. The aim of the present work is to contribute to a better understanding of such damage mechanisms by providing original results on the impact of classical glass surface machining on the laser-induced damage threshold. For this purpose, glass samples were prepared with well-defined process conditions in terms of the used lapping and polishing agents and suspensions. Further, the samples were post-processed by atmospheric pressure plasma for precision cleaning. The laser-induced damage threshold and surface contamination by residues from the manufacturing process were determined before and after plasma post-processing. It is shown that the polishing suspension concentration has a certain impact on the laser-induced damage threshold and surface contamination by residues from used working materials. The highest damage threshold of 15.2 J/cm² is found for the lowest surface contamination by carbon which occurs in the case of the highest polishing suspension concentration. After plasma treatment for merely 60 s, this value was increased to 20.3 J/cm² due to the removal of surface-adherent carbon. The results thus imply that the laser-induced damage threshold can notably be increased by first choosing appropriate process parameters during classical manufacturing and second plasma post-processing for surface finishing.

scholarly journals Increasing the Laser-Induced Damage Threshold of Optical Components by Atmospheric Pressure Plasma Surface Finishing

2019 ◽  
Vol 215 ◽  
pp. 01003
Author(s):  
Christoph Gerhard ◽  
Marco Stappenbeck ◽  
Daniel Tasche
Keyword(s):  
Atmospheric Pressure ◽  
Discharge Plasma ◽  
Atmospheric Pressure Plasma ◽  
Damage Threshold ◽  
Surface Cleaning ◽  
Surface Finishing ◽  
Dielectric Barrier Discharge Plasma ◽  
Optical Components ◽  
Barrier Discharge Plasma ◽  
Laser Induced Damage

In this contribution, a plasma-based approach for finishing optics surfaces is introduced. Experiments were performed on classically manufactured zinc crown glass and sapphire. It is shown that the use of direct dielectric barrier discharge plasma at atmospheric pressure allows the removal of surface-adherent carbonaceous contaminations that were induced by classical manufacturing. Moreover, the use of such plasma leads to a certain decrease in surface roughness. Both effects, surface cleaning and smoothing finally increase the laser-induced damage threshold of optical components.

Laser damage investigation in RbTiOPO 4 crystals: a study on the anisotropy of the laser induced damage threshold

2006 ◽  
Author(s):  
Anne Hildenbrand ◽  
Frank Wagner ◽  
Jean-Yves Natoli ◽  
Mireille Commandre ◽  
Hervé Albrecht ◽  
...  
Keyword(s):  
Damage Threshold ◽  
Laser Damage ◽  
Laser Induced Damage ◽  
Damage Investigation

Absorption and Laser Induced Damage Threshold of TiO2Single Films under Different Process Conditions

2012 ◽  
Vol 39 (4) ◽  
pp. 0407001 ◽  
Author(s):  
徐俊海 Xu Junhai ◽  
赵元安 Zhao Yuan′an ◽  
邵建达 Shao Jianda ◽  
范正修 Fan Zhengxiu
Keyword(s):  
Damage Threshold ◽  
Process Conditions ◽  
Laser Induced Damage

scholarly journals Study on the Absorption Characteristics and Laser Damage Properties of Fused Silica Optics under Flexible Polishing and Shallow DCE Process

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1226
Author(s):  
Wanli Zhang ◽  
Feng Shi ◽  
Ci Song ◽  
Ye Tian ◽  
Yongxiang Shen
Keyword(s):  
Chemical Etching ◽  
Ion Beam ◽  
Damage Threshold ◽  
Fused Silica ◽  
Laser Damage ◽  
Damage Resistance ◽  
Etching Depth ◽  
Treatment Processes ◽  
Laser Induced Damage ◽  
Combined Technique

The enhancement of laser damage resistance of fused silica optics was a hotspot in scientific research. At present, a variety of modern processes have been produced to improve the laser induced damage threshold (LIDT) of fused silica optics. They included pre-treatment processes represented by flexible computer controlled optical surfacing (CCOS), magnetorheological finishing (MRF), ion beam finishing (IBF), and post-treatment processes represented by dynamic chemical etching (DCE). These have achieved remarkable results. However, there are still some problems that need to be solved urgently, such as excessive material removal, surface accuracy fluctuation in the DCE process, and the pollution in MRF process, etc. In view of above problems, an MRF, CCOS, IBF and shallow DCE combined technique was used to process fused silica optics. The surface morphology could be greatly controlled and chemical etching depth was reduced, while the LIDT increased steadily. After processing by this combined technique, the LIDT increased to 12.1 J/cm2 and the laser damage resistance properties of fused silica were significantly enhanced. In general, the MRF, IBF, CCOS and shallow DCE combined technique brought much help to the enhancement of laser damage resistance of fused silica, and could be used as a process route in the manufacturing process of fused silica.

scholarly journals Effects of Ion Beam Etching on the Nanoscale Damage Precursor Evolution of Fused Silica

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1294
Author(s):  
Yaoyu Zhong ◽  
Yifan Dai ◽  
Feng Shi ◽  
Ci Song ◽  
Ye Tian ◽  
...  
Keyword(s):  
Silica Surface ◽  
Ion Beam ◽  
Damage Threshold ◽  
Fused Silica ◽  
Structural Defects ◽  
Laser Damage ◽  
Material Structure ◽  
Ion Beam Etching ◽  
Damage Resistance ◽  
Laser Induced Damage

Nanoscale laser damage precursors generated from fabrication have emerged as a new bottleneck that limits the laser damage resistance improvement of fused silica optics. In this paper, ion beam etching (IBE) technology is performed to investigate the evolutions of some nanoscale damage precursors (such as contamination and chemical structural defects) in different ion beam etched depths. Surface material structure analyses and laser damage resistance measurements are conducted. The results reveal that IBE has an evident cleaning effect on surfaces. Impurity contamination beneath the polishing redeposition layer can be mitigated through IBE. Chemical structural defects can be significantly reduced, and surface densification is weakened after IBE without damaging the precision of the fused silica surface. The photothermal absorption on the fused silica surface can be decreased by 41.2%, and the laser-induced damage threshold can be raised by 15.2% after IBE at 250 nm. This work serves as an important reference for characterizing nanoscale damage precursors and using IBE technology to increase the laser damage resistance of fused silica optics.

scholarly journals Substrate Cleaning Processes and Their Influence on the Laser Resistance of Anti-Reflective Coatings

2020 ◽  
Vol 10 (23) ◽  
pp. 8496
Author(s):  
Thomas Gischkat ◽  
Daniel Schachtler ◽  
Igor Stevanovic ◽  
Zoltan Balogh-Michels ◽  
Roelene Botha ◽  
...  
Keyword(s):  
Particle Density ◽  
Ion Beam ◽  
Damage Threshold ◽  
Fused Silica ◽  
Limiting Factors ◽  
Laser Damage ◽  
Angle Of Incidence ◽  
Laser Induced Damage ◽  
Reflective Coatings ◽  
Substrate Cleaning

Substrate cleaning prior to coating has a strong influence on the performance of the optical component. Exemplary, none or inadequate cleaning reduces the resistance against laser irradiation drastically. Especially in laser components coated with anti-reflective layers, the interface between substrate and coating is one of the most limiting factors. This study investigates different precision cleaning processes and their influence on the laser resistance of ion-beam sputtered anti-reflective coatings. Therefore, a SiO2/Ta2O5 multilayer anti-reflective coating for a wavelength of 1064 nm and a normal angle of incidence was deposited onto high-quality fused silica substrates. Prior to deposition, the substrates were cleaned with various cleaning processes using different solutions and ultrasonic frequencies. To characterize the cleaned surface quality, the surfaces were analyzed with respect to root-mean-square (RMS) roughness and particle density. Laser damage was measured using a 1064 nm ns-pulsed laser test bench. It was found that an alcoholic pre-clean is recommendable to prevent laser damage caused by organic films remaining from the polishing process. The applied ultrasonic frequencies strongly influenced the particle density down to the sub-micrometer range and in consequence, the laser-induced damage threshold (LIDT). Ultrasonic cleaning at excessive power levels can reduce laser resistance.

Laser Induced Damage Threshold Measurements at the Microscopic Level

1992 ◽  
Vol 285 ◽  
Author(s):  
Allen D. Zwan ◽  
David R. Miller
Keyword(s):  
Single Crystal Silicon ◽  
Damage Threshold ◽  
Damage Mechanism ◽  
Laser Damage Threshold ◽  
Laser Damage ◽  
Plasma Damage ◽  
Crystal Silicon ◽  
Thermally Induced ◽  
Laser Induced Damage

ABSTRACTWe have (tudied the laser damage threshold to silver films (500Å - 1000Å) grown on single crystal silicon <100>, in a newly developed laser damage UHV system at pressures of 10−1 torr. A 1.06μm Nd:Glass laser is used to damage the mirror surfaces in 1-on-1 pulse studies. In-situ damage characterization includes Auger, reflectivity of the primary beam, diffuse scattering of a helium-neon laser, and mass spectrometry detection of desorbed surface species. External characterization includes optical microscopy and SEM. All in-situ damage probes are well correlated and baseline damage occurs at fluences near 3.4 MW/cm2. Time-of-flight to the mass spectrometer shows ejected particles with energies in the 5 to 10 eV range indicating a plasma damage mechanism. Prior to typical thermally induced damage the external microscopy shows well defined precursor morphology changes which appear as feather-like microstructure at the submicron level.

scholarly journals Diagnosing laser-induced damage to optical thin films using peak sound pressure of shock waves

2017 ◽  
Vol 35 (2) ◽  
pp. 259-264 ◽  
Author(s):  
G. Jinman ◽  
S. Junhong ◽  
W. Shenjiang ◽  
X. Junqi ◽  
C. Lei ◽  
...  
Keyword(s):  
Thin Films ◽  
Service Life ◽  
Shock Waves ◽  
Sound Pressure ◽  
Damage Threshold ◽  
Propagation Distance ◽  
Optical Systems ◽  
Laser Damage ◽  
Laser Induced Damage ◽  
The Relationship

AbstractLaser-induced damage threshold (LIDT) is an important parameter used to describe the resistance of optical thin films to laser damage. The service life and cost of optical systems depend on the LIDT of the film. Thus, the precision with which the film's LIDT can be measured impacts how well the service life and cost of the system can be predicted. Therefore, it is important to find a precise approach to diagnose a film's laser-induced damage. In this paper, characteristics of the peak sound pressure of laser-induced plasma shock waves from thin films have been systematically investigated experimentally. We found that the peak sound pressure decays rapidly with propagation distance during air transmission. Based on a theoretical analysis of the relationship between the peak sound pressure and the laser damage to a film, we propose a method for diagnosing laser damage using the peak sound pressure of a thin film's shock wave. Our results show that this method can simplify implementation, which will provide a new method with which to diagnose laser damage to thin films.

Dose-dependent optical properties and laser damage of helium-implanted sapphire

2015 ◽  
Vol 93 (7) ◽  
pp. 776-783
Author(s):  
Mian Zhong ◽  
Liang Yang ◽  
Guixia Yang ◽  
Zhonghua Yan ◽  
Zhijie Li ◽  
...  
Keyword(s):  
Optical Properties ◽  
Damage Threshold ◽  
Laser Damage ◽  
Photoluminescence Band ◽  
Infrared Band ◽  
Absorption Bands ◽  
Microscopic Images ◽  
Laser Induced Damage ◽  
Surface Morphologies ◽  
Implantation Fluence

A series of single crystalline Al2O3 samples are implanted with He+ ions at different nominal fluences up to 1 × 1018 ions/cm2 at room temperature. The microstructure evolution and optical properties as well as laser-induced damage threshold are investigated. Optical microscopic images show that the density and amount of defects increase with increasing implantation fluence. In addition, atomic force microscopic images indicate that the surface morphologies have changed distinctly when the fluence reaches 5 × 1017 ions/cm2 and above. After helium implantation, broad purple and green–yellow absorption bands as well as an obvious photoluminescence band at 330 nm are observed, respectively. With the increase of implantation fluence, the intensities of absorption bands increase greatly, whereas the intensity of the photoluminescence band decreases and tends to saturation. The original strong infrared band shifts and broadens with increasing implantation fluence. The mechanism for the shift and broadening of the infrared band is discussed. After laser irradiation, it is found that the implantation fluence has great effect on the laser-induced damage threshold, which decreases significantly from 5.43 J/cm2 to 4.62, 3.71, 2.64, and 1.80 J/cm2 with increasing implantation fluence. A mechanism for the degradation of laser damage resistance is presented.

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