scholarly journals Investigation of surface damage precursor evolutions and laser-induced damage threshold improvement mechanism during Ion beam etching of fused silica

2016 ◽  
Vol 24 (18) ◽  
pp. 20842 ◽  
Author(s):  
Feng Shi ◽  
Yaoyu Zhong ◽  
Yifan Dai ◽  
Xiaoqiang Peng ◽  
Mingjin Xu ◽  
...  
Keyword(s):  
Ion Beam ◽  
Damage Threshold ◽  
Surface Damage ◽  
Fused Silica ◽  
Ion Beam Etching ◽  
Damage Precursor ◽  
Laser Induced Damage

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 Investigation of laser-induced damage threshold improvement mechanism during ion beam sputtering of fused silica

2017 ◽  
Vol 25 (23) ◽  
pp. 29260 ◽  
Author(s):  
Mingjin Xu ◽  
Feng Shi ◽  
Lin Zhou ◽  
Yifan Dai ◽  
Xiaoqiang Peng ◽  
...  
Keyword(s):  
Ion Beam ◽  
Damage Threshold ◽  
Fused Silica ◽  
Ion Beam Sputtering ◽  
Beam Sputtering ◽  
Laser Induced Damage

scholarly journals Detailed near-surface nanoscale damage precursor measurement and characterization of fused silica optics assisted by ion beam etching

2019 ◽  
Vol 27 (8) ◽  
pp. 10826 ◽  
Author(s):  
Yaoyu Zhong ◽  
Feng Shi ◽  
Ye Tian ◽  
Yifan Dai ◽  
Ci Song ◽  
...  
Keyword(s):  
Ion Beam ◽  
Fused Silica ◽  
Ion Beam Etching ◽  
Near Surface ◽  
Damage Precursor

scholarly journals SSD detection on LIDT tested coated Fused Silica samples

2021 ◽  
Vol 255 ◽  
pp. 03009
Author(s):  
Heidi Cattaneo ◽  
Daniel Schachtler ◽  
Roelene Botha ◽  
Oliver Fähnle
Keyword(s):  
Laser Energy ◽  
Substrate Surface ◽  
Single Layer ◽  
Damage Threshold ◽  
Surface Damage ◽  
Laser Pulses ◽  
Fused Silica ◽  
Small Surface ◽  
Additional Information ◽  
Laser Induced Damage

Material changes and Sub-Surface Damage (SSD) under Laser Induced Damage Threshold (LIDT) testing sites were investigated on 3 diverse single layer coated transparent fused silica samples to obtain additional information on damage precursors on these samples. As a detection method, photothermal deflection technique utilizing a resonant UV laser beam was used. The local variations in UV absorption and probe beam transmittance due to previous exposure to high fluence laser pulses were strongly dependent on the coating itself and on the laser energy used during the LIDT testing. Also the obtained LIDT values differ from coating to coating. Detected effects on the coatings and substrate surface beneath ranged from small surface dislocations to complete coating damage with material transformations. Additional absorbing damage precursors were found close to the damaged sites.

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.

Anisotropic ion beam etching of fused silica to mitigate subsurface damage

2020 ◽  
Vol 34 (08) ◽  
pp. 2050060 ◽  
Author(s):  
Bo Li ◽  
Xia Xiang ◽  
Chengxiang Tian ◽  
Chunyuan Hou ◽  
Wei Liao ◽  
...  
Keyword(s):  
Surface Quality ◽  
Surface Defects ◽  
Silica Surface ◽  
Incident Angle ◽  
Ion Beam ◽  
Damage Threshold ◽  
Fused Silica ◽  
Laser Damage Threshold ◽  
Laser Damage ◽  
Ion Beam Etching

The laser damage resistance of fused silica optics depends significantly on the surface quality. In this work, anisotropic etching with inert ion beams at various ion incident angles was performed to investigate the evolution of the fused silica surface. The results show that the surface is smoothed when the incident angle is below [Formula: see text]. However, the fused silica surface starts to become coarse owing to the formation of nanostructures on the surface when the incident angle exceeds [Formula: see text]. Further, ion beam etching at a large incident angle of [Formula: see text] removes subsurface defects and less induces nanostructures, resulting in reduction of the surface roughness. The concentrations of impurities and defects are both significantly reduced after ion beam etching. The surface quality, subsurface and surface defects, and surface impurities determine the variation in the laser damage threshold of fused silica with the ion incident angle. The results demonstrate successful application of ion beam etching to improve the laser damage resistant characteristics of fused silica optics. Ion beam etching is a very versatile tool that provides physical erosion to anisotropically mitigate surface damage of fused silica.

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.

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