Evaluation of nonlinear absorptivity in internal modification of bulk glass by ultrashort laser pulses
Evaluation of nonlinear absorptivity in internal modification of bulk glass by ultrashort laser pulses
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DOI：
10.1364/oe.19.010714
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发表时间：
2011-05-23
期刊：
影响因子：
3.8
通讯作者：
Schmidt, Michael
中科院分区：
文献类型：
--
作者：
Miyamoto, Isamu;Cvecek, Kristian;Schmidt, Michael
提出了热传导模型，模拟了大块玻璃内部改性过程中超短激光脉冲的非线性吸收率。模拟的非线性吸收率与硼硅酸盐玻璃中 10ps 脉冲持续时间的各种激光参数的最大不确定性为 +/- 3% 的实验值一致。非线性吸收率随着激光脉冲能量和重复频率的增加而增加，高达90%。平均吸收激光功率的增加伴随着激光吸收区域向激光源的扩展。三维热源的瞬态热传导模型表明，激光能量被雪崩电离吸收，雪崩电离由热激发自由电子在远离焦点的位置以高于 100kHz 的脉冲重复率产生。 (C) 2011 美国光学学会
Thermal conduction model is presented, by which nonlinear absorptivity of ultrashort laser pulses in internal modification of bulk glass is simulated. The simulated nonlinear absorptivity agrees with experimental values with maximum uncertainty of +/- 3% in a wide range of laser parameters at 10ps pulse duration in borosilicate glass. The nonlinear absorptivity increases with increasing energy and repetition rate of the laser pulse, reaching as high as 90%. The increase in the average absorbed laser power is accompanied by the extension of the laser-absorption region toward the laser source. Transient thermal conduction model for three-dimensional heat source shows that laser energy is absorbed by avalanche ionization seeded by thermally excited free-electrons at locations apart from the focus at pulse repetition rates higher than 100kHz. (C) 2011 Optical Society of America