对不同辐照条件下近红外飞秒激光在K9玻璃内部诱导产生的暗化现象和永久性折射率改变进行了实验研究。通过辐照前后的显微镜图片、吸收光谱、电子自旋共振谱(ESR)以及激光衍射实验,分析了K9玻璃中暗化现象产生的微观过程,发现暗化是由诱导产生的空穴型色心引起的。暗化程度和折射率改变随激光强度、扫描速度、扫描行间距变化而变化。光致色心的形成与非线性电离有关。对折射率永久性改变进行了简单说明,其机理仍在探索中。

Femtosecond laser induced darkening and permanent refractive index changes in K9 glass under different radiation conditions were experimentally studied. The micro-process of darkening generation in K9 glass was analyzed depending on the results of microscope photograph, absorption spectra, electron spin resonance spectra (ESR) and laser diffraction. It was found that hole-trapped color centers give rise to the darkening generation. Darkening and refractive index change varied with laser intensity, scan speed and line interval. Nonlinear ionization enhanced color center formation. Permanent refractive index changes were explained simply. The mechanism was still under discussion.