An irrecoverable change in the refractive index of plasma self-channeled silica fibers caused by femtosecond optical pulses
An irrecoverable change in the refractive index of plasma self-channeled silica fibers caused by femtosecond optical pulses
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飞秒光脉冲引起的等离子体自通道石英光纤折射率的不可恢复的变化
DOI：
10.1063/1.1593835
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发表时间：
2003
影响因子：
4
通讯作者：
K. Midorikawa
中科院分区：
文献类型：
--
作者：
I. Park;H. Ju;A. Avilov;S. Choh;E. Koh;Sung;H. Kumagai;K. Midorikawa
本文研究了110 fs钛蓝宝石激光在790和395 nm处自聚焦至5 μm的改性光纤的物理性质。光纤芯中的光学修饰区折射率大于未损坏区的折射率。损伤区电子衍射结果表明，非晶态SiO2晶化成方石晶石结构是导致指数从1.457提高到1.480的主要原因。在光学损伤期间，硅和氧等离子体最好重新结合以产生负责结晶的新键。一些残余的硅等离子体导致众所周知的E '中心缺陷，其密度随输入光强呈抛物线增长。
We have investigated the physical properties of modified optical fibers through which 110 fs Ti:sapphire laser beam is self-focused down to 5 μm at 790 and 395 nm. The optically modified region in the fiber core exhibits the refractive index greater than that in the undamaged region. Electron diffraction measurements for the damaged region reveal that the enhancement of index from 1.457 to 1.480 is induced by the crystallization of amorphous SiO2 into a cristobalite structure. During the optical damaging, silicon and oxygen plasma preferably recombine to result in new bonds responsible for the crystallization. Some of the remnant silicon plasma lead to defects of the well-known E′-center, whose density increased parabolically with the input light intensity.