scholarly journals Performance of rapid-grown KDP crystals with continuous filtration

2015 ◽  
Vol 3 ◽  
Author(s):  
Guohang Hu ◽  
Yueliang Wang ◽  
Junxiu Chang ◽  
Xiaoyi Xie ◽  
Yuanan Zhao ◽  
...  
Keyword(s):  
Near Infrared ◽  
Laser Damage ◽  
Damage Resistance ◽  
Damage Initiation ◽  
Micron Size ◽  
Continuous Filtration ◽  
Laser Induced Damage ◽  
Almost All ◽  
Lower Correlation ◽  
Kdp Crystals

Rapid growth processing of KDP crystals was improved by employing continuous filtration to eliminate bulk defects. The performances of the KDP crystals, including scattering defects, laser damage resistance and transmittance, were measured and analyzed. Compared with rapid-grown KDP without continuous filtration, the transmittance in the near-infrared was increased by at least 2%, almost all of ‘micron size’ defects were eliminated and ‘sub-micron size’ defects were decreased by approximately 90%. Laser damage testing revealed that the laser-induced damage thresholds (LIDTs), as well as the consistency of the LIDTs from sample to sample, were improved greatly. Moreover, it identified that ‘micron size’ defects were the precursors which initiated laser damage at relative lower laser fluence (4–6 J cm−2), and there was a lower correlation between smaller size scattering defects and laser damage initiation. The improved consistency in the LIDTs, attributed to elimination of ‘micron size’ defects, and LIDT enhancement originated from the decreased absorption of the KDP crystals.

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.

Laser Damage Resistance of Photo-Thermo-Refractive Glass Bragg Gratings

2004 ◽  
Author(s):  
Leonid B. Glebov ◽  
Larissa N. Glebova ◽  
Vadim I. Smirnov ◽  
Mark Dubinskii ◽  
Larry D. Merkle ◽  
...  
Keyword(s):  
Bragg Gratings ◽  
Laser Damage ◽  
Damage Resistance

Laser damage resistance of ion-beam sputtered Sc2O3/SiO2 mixture optical coatings

2013 ◽  
Vol 52 (7) ◽  
pp. 1368 ◽  
Author(s):  
Mathias Mende ◽  
Stefan Schrameyer ◽  
Henrik Ehlers ◽  
Detlev Ristau ◽  
Laurent Gallais
Keyword(s):  
Ion Beam ◽  
Laser Damage ◽  
Optical Coatings ◽  
Damage Resistance

Optimization of laser-damage resistance of evaporated hafnia films at 351nm

2008 ◽  
Author(s):  
J. B. Oliver ◽  
S. Papernov ◽  
A. W. Schmid ◽  
J. C. Lambropoulos
Keyword(s):  
Laser Damage ◽  
Damage Resistance

Bulk laser damage of large-size KDP crystals obtained at various crystal growth conditions

1994 ◽  
Author(s):  
Marina I. Kolybayeva ◽  
Igor M. Pritula ◽  
Viacheslav M. Puzikov ◽  
Vitaly I. Salo ◽  
Serge V. Garnov ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Growth Conditions ◽  
Laser Damage ◽  
Large Size ◽  
Kdp Crystals

Damage Characterization in Glass/Epoxy Composite Laminates under Normal and Oblique Planes of Cyclic Indentation Loading with AE Monitoring

2021 ◽  
Vol 79 (1) ◽  
pp. 61-77
Author(s):  
A Jayababu ◽  
V Arumugam ◽  
B Rajesh ◽  
C Suresh Kumar
Keyword(s):  
Compressive Strength ◽  
Acoustic Emission ◽  
Cyclic Loading ◽  
Composite Laminates ◽  
Epoxy Composite ◽  
Damage Resistance ◽  
Damage Initiation ◽  
Residual Compressive Strength ◽  
Cyclic Indentation ◽  
Indentation Damage

This work focuses on the experimental investigation of indentation damage resistance in different stacking sequences of glass/epoxy composite laminates under cyclic loading on normal (0°) and oblique (20°) planes. The stacking sequence, such as unidirectional [0]12, angle ply [±45]6S, and cross ply [0/90]6S, were subjected to cyclic indentation loading and monitoring by acoustic emission testing (AE). The laminates were loaded at the center using a hemispherical steel indenter with a 12.7 mm diameter. The cyclic indentation loading was performed at displacements from 0.5 to 3 mm with an increment of 0.5 mm in each cycle. Subsequently, the residual compressive strength of the post-indented laminates was estimated by testing them under in-plane loading, once again with AE monitoring. Mechanical responses such as peak load, absorbed energy, stiffness, residual dent, and damage area were used for the quantification of the indentation-induced damage. The normalized AE cumulative counts, AE energy, and Felicity ratio were used for monitoring the damage initiation and propagation. Moreover, the discrete wavelet analysis of acoustic emission signals and fast Fourier transform enabled the calculation of the peak frequency content of each damage mechanism. The results showed that the cross-ply laminates had superior indentation damage resistance over angle ply and unidirectional (UD) laminates under normal and oblique planes of cyclic loading. However, the conclusion from the results was that UD laminates showed a better reduction in residual compressive strength than the other laminate configurations.

Relation of optical properties and femtosecond laser damage resistance for Al2O3/AlF3 and Al2O3/SiO2 composite coatings

2014 ◽  
Vol 53 (4) ◽  
pp. A383 ◽  
Author(s):  
Mathias Mende ◽  
Istvan Balasa ◽  
Henrik Ehlers ◽  
Detlev Ristau ◽  
Dam-be Douti ◽  
...  
Keyword(s):  
Optical Properties ◽  
Femtosecond Laser ◽  
Composite Coatings ◽  
Laser Damage ◽  
Damage Resistance
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