PEG含量对多孔膜光学带隙及激光损伤特性的影响  

Influence of PEG content on optical band gap and laser damage characteristics of porous films

作　　者：孙少斌 徐均琪[1] 苏俊宏[1] 李阳[1] 王通 刘政[2] SUN Shaobin;XU Junqi;SU Junhong;LI Yang;WANG Tong;LIU Zheng(Shaanxi Province Thin Film Technology and Optical Test Open Key Laboratory,Xi'an Technological University,Xi'an 710021,China;Advanced Optical Manufacturing Technology Joint Laboratory,Xi'an Institute of Optics and Precision Mechanics of CAS,Xi'an 710119,China)

机构地区：[1]西安工业大学陕西省薄膜技术与光学检测重点实验室,陕西西安710021 [2]中国科学院西安光学精密机械研究所先进光学制造技术联合实验室,陕西西安710119

出　　处：《应用光学》2024年第4期841-848,共8页Journal of Applied Optics

基　　金：国家自然科学基金项目(62205263)。

摘　　要：采用溶胶凝胶技术结合旋涂法,在石英基底及Si基底上分别制备了孔隙率不同的TiO_(2)和SiO_(2)薄膜,并对两者的光学及激光损伤特性进行了研究。根据透射光谱曲线计算出薄膜的光学带隙,发现光学带隙随着孔隙率的增大而增大,TiO_(2)薄膜的光学带隙大小为3.75 eV~3.97 eV,SiO_(2)薄膜的光学带隙大小为3.52 eV~3.78 eV。椭偏测量结果表明,当聚乙二醇(polyethylene glycol,PEG)质量分数从0、0.8%、4.0%提高至8.0%时,在波长1064 nm处,TiO_(2)薄膜的孔隙率从11.5%、14.1%、30.9%增大至38.7%,折射率从2.0635、2.0165、1.7481降低至1.6409;SiO_(2)薄膜的孔隙率从4.04%、4.6%、5.7%提升至13.9%,折射率从1.4386、1.4358、1.4204降低至1.3879。除PEG质量分数为0.8%的TiO_(2)薄膜外,所有TiO_(2)和SiO_(2)薄膜样品的消光系数均优于10-3,说明薄膜的吸收较小。薄膜的激光损伤阈值(laser induced damage threshold,LIDT)受孔隙率的影响较大,孔隙率越大,TiO_(2)薄膜的激光损伤阈值越高,其值最高可达16.7 J/cm~2;而SiO_(2)薄膜的激光损伤阈值较未添加PEG的激光损伤阈值并未提高,当PEG质量分数从0.8%增加到8.0%时,SiO_(2)薄膜的激光损伤阈值提高了1.9 J/cm~2。总而言之,提高孔隙率有助于提高薄膜的抗激光损伤性能。TiO_(2)and SiO_(2)films with different porosity were prepared on quartz substrate and Si substrate respectively by sol-gel technique combined with spin coating method,and the optical and laser damage characteristics of both films were investigated.The optical band gap of the films was calculated based on the transmission spectral curves.It was found that the optical band gap increased with the increase of porosity,the optical band gap size of TiO_(2)films ranged from 3.75 eV to 3.97 eV,and that of SiO_(2)films ranged from 3.52 eV to 3.78 eV.The ellipsometry measurement results show that when the mass fraction of polyethylene glycol(PEG)was increased from 0,0.8%,4%to 8%at a wavelength of 1064 nm,the porosity of TiO_(2)films increased from 11.5%,14.1%,30.9%to 38.7%,and the refractive index decreased from 2.0635,2.0165,1.7481 to 1.6409;the porosity of SiO_(2)films increased from 4.04%,4.6%,5.7%to 13.9%,and the refractive index decreased from 1.4386,1.4358,1.4204 to 1.3879.The extinction coefficients of all TiO_(2)and SiO_(2)film samples are better than 10-3 except for the TiO_(2)film with PEG mass fraction of 0.8%,which indicates that the absorption of the films is smaller.The laser induced damage threshold(LIDT)of the films is greatly influenced by the porosity,and the larger the porosity,the higher the LIDT of TiO_(2)films,with a value up to 16.7 J/cm2.However,the LIDT of SiO_(2)film is not improved compared with that without PEG,and when the PEG mass fraction increased from 0.8%to 8%,the LIDT of SiO_(2)film increased by 1.9 J/cm2.In summary,improving the porosity helps to improve the laser damage resistance of the film.

关 键 词：溶胶凝胶法 TiO_(2) SiO_(2) 聚乙二醇 光学带隙 激光损伤阈值 

分 类 号：O484.4[理学—固体物理]