Thermomechanical analysis of nodule damage in HfO2/SiO2 multilayer coatings

• 来源期刊: 中国光学快报（英文版）
• 年，卷（期）: 2011,（11）
• 页码范围: 82-85
• 页数: 4页
• 语种: 英文
• DOI: 10.3788/COL201109.103101

摘要

Samples with nodular defects grown from gold nanoparticles are prepared,and laser induced damage tests are conducted on them.Nodular defects,which are in critical state of damage,are cross-sectioned by focusing on the ion beam and by imaging using a field emission scanning electron microscope.The crosssectional profile shows that cracks are generated and propagated along the nodular boundaries and the HfO2/SiO2 interface,or are even melted.The thermomechanical process induced by the heated seed region is analyzed based on the calculations of temperature increase and thermal stress.The numerical results give the critical temperature of the seed region and the thermal stress for crack generation,irradiated with threshold fluence.The numerical results are in good agreement with the experimental ones.Nodular defect,a typical defect in multilayer coatings,largely limits the improvement of the laser-induced damage threshold (LIDT) in the nanosecond regime and thus has been widely investigated.Electric field enhancement in the nodule,induced by the microlens effect of the dome structure of nodular defects,is an important factor in reducing the LIDT[1-5].Recently,Liu et al.