Rear-surface light intensification caused by a Hertzian-conical crack in 355-nm silica optics  

作　　者：章春来 袁晓东 向霞 王治国 刘春明 李莉 贺少勃 祖小涛 

机构地区：[1]School of Physical Electronics,University of Electronic Science and Technology of China [2]Research Center of Laser Fusion,China Academy of Engineering Physics

出　　处：《Chinese Physics B》2012年第9期321-327,共7页中国物理B（英文版）

基　　金：Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No.10904008);the Joint Fund of the National Natural Science Foundation of China and the China Academy of Engineering Physics (GrantNo. 11076008);the Scientific Research Foundation for the Central Universities of China (Grant Nos.ZYGX2009X007,ZYGX2010J045, and ZYGX2011J043)

摘　　要：Theoretical studies show that a Hertzian-conical crack can be considered to be composed of double cone faces for simplicity. In the present study, the three-dimensional finite-difference time-domain method is employed to quantify the electric-field distribution within the subsurface in the presence of such a defect under normal incidence irradiation. Both impurities （inside the crack） and the chemical etching have been investigated. The results show that the maximum electric field amplitude │E│max is 9.57374 V/m when the relative dielectric constant of transparent impurity equals 8.5. And the near-field modulation will be improved if the crack is filled with the remainder polishing powders or water vapor/drops. Meanwhile, the laser-induced initial damage moves to the glass-air surface. In the etched section, the magnitude of intensification is strongly dependent on the inclination angle θ. There will be a highest modulation when θ is around π/6, and the maximum value of IEImax is 18.57314 V/m. When θ ranges from π/θ to π/4, the light intensity enhancement factor can easily be larger than 100, and the modulation follows a decreasing trend. On the other hand, the modulation curves become smooth when θ〉π/4 or θ 〈 π/8.Theoretical studies show that a Hertzian-conical crack can be considered to be composed of double cone faces for simplicity. In the present study, the three-dimensional finite-difference time-domain method is employed to quantify the electric-field distribution within the subsurface in the presence of such a defect under normal incidence irradiation. Both impurities （inside the crack） and the chemical etching have been investigated. The results show that the maximum electric field amplitude │E│max is 9.57374 V/m when the relative dielectric constant of transparent impurity equals 8.5. And the near-field modulation will be improved if the crack is filled with the remainder polishing powders or water vapor/drops. Meanwhile, the laser-induced initial damage moves to the glass-air surface. In the etched section, the magnitude of intensification is strongly dependent on the inclination angle θ. There will be a highest modulation when θ is around π/6, and the maximum value of IEImax is 18.57314 V/m. When θ ranges from π/θ to π/4, the light intensity enhancement factor can easily be larger than 100, and the modulation follows a decreasing trend. On the other hand, the modulation curves become smooth when θ〉π/4 or θ 〈 π/8.

关 键 词：fused silica wet etching Hertzian-conical crack finite-difference time-domain method 

分 类 号：TN36[电子电信—物理电子学]