【摘要】 实验研究了ns激光脉冲聚焦到BK7玻璃表面发生电离时玻璃的损伤形貌,并基于激光等离子体的特性对损伤特征进行了分析。研究发现:激光击穿产生的激光等离子体具有高温高压的特性以及较宽的光谱分布,这些特性对脆性BK7玻璃的损伤特性有决定性的影响。激光等离子体发射光谱的波长分布远远小于入射激光的波长,其电离效应大大增强,使玻璃材料更易发生击穿;等离子体的高温特性会对脆性玻璃进行熔蚀;冲击波作用使损伤中心处发生充分断裂,并绕中心产生环状的破坏;发生环形断裂的同时,张力作用会使得玻璃产生沿着径向的裂纹,其间折射率发生明显的变化。更多还原

【Abstract】 In the experiment,topography damage was investigated during ionization when ns laser pulse focused on the surface of BK7 glass,and the properties of damage was analyzed based on the characteristics of laser plasmas.Study shows that laser plasma caused by laser breakdown has a property of high temperature and high pressure as well as a relatively wide spectral distribution which play a dominant role in the damage to brittle BK7 glass: wavelength distribution of laser plasma emission spectrum is far less than laser wavelength of incidence,so that its ionization effects are greatly strengthened and it produces breakdown of vitreous material more easily;high temperature property of laser plasma causes corrosion to brittle glass;shock wave makes full fracture occur in the center of the damage,and causes circular destruction around the center;in the meantime,tension brings radial cracks to the glass,and its refractive index changes a lot.更多还原