离子注入对聚对苯乙炔衍生物三阶非线性光学极化率的影响

Effects of ion implantation on third-order nonlinear optical susceptibilities of poly （p-phenylene vinylene） derivative

利用能量为25keV，剂量为3．8×10^15-9．6×10^16ions／cm^2的氮正离子（N^＋）对聚（2，5-二己氧基）对苯乙炔（PDHOPV）薄膜进行注入改性研究。紫外-可见吸收光谱显示，注入离子在PDHOPV薄膜内部引入杂质能级，破坏分子的共轭结构，随着注入剂量增加，吸收边逐渐向长波方向移动，且分子激发态和基态间的光学禁带宽度由2．07eV减小至1．65eV。采用简并四波混频（DFWM）技术研究了离子注入对PDHOPV薄膜三阶非线性光学极化率的性能。结果表明，未注入薄膜的三阶非线性光学极化率（X^（3））为9．61×10^-10esu，随着注入剂量增加，X^（3）逐渐增大，当注入剂量达到3．8×10^16ions／cm^2。时，X^（3）值增加到最大值为8.44×10^-9esu。

In this paper, poly （2,5-dihexyloxy）-p-phenylene vinylene （PDHOPV） films were implanted by nitrogen ion（N^＋） with the dose ranging from 3.8×10^15 to 9.6×10^16 ions/cm^2 at an energy of 25 keV. UV-Vis spectra exhibited that the optical absorption in visible region was improved by ion implantation followed by a red shift of optical absorption threshold and the optical bandgap （Eg） between excited state and base state was reduced from 2.07 eV to 1.65 eV with the increase of ion dose. The third-order nonlinear optical susceptibilities （X^（3）） were measured by degenerate four-wave mixing （DFWM） technique. The results demonstrated that the X^（3） value of pristine PDHOPV film was 9.61 ×10^-10 esu and became larger with the ion dose increasing and reached to the maximum value of 8.44×10^-9 esu at an ion dose of 3.8×10^16 ions/cm^2.