不同干涉激光偏振态对偶氮分子玻璃表面起伏光栅形成的影响  

Effect of Polarization of Ar^+ Laser Beams on Surface-Relief-Grating Formation Behavior of Molecular Azo Glass

作　　者：郭妙才[1] 徐则达[2] 王晓工[1] 

机构地区：[1]清华大学化工系高分子研究所教育部先进材料重点实验室,北京100084 [2]北京航空航天大学物理系,北京100083

出　　处：《光学学报》2009年第3期767-771,共5页Acta Optica Sinica

基　　金：国家863计划(2007AA03Z409)资助课题。

摘　　要：研究了在不同偏振态干涉Ar^+激光作用下,一种偶氮无定形分子玻璃膜表面形成起伏光栅的特性。实验采用p+p,p+s,RCP+LCP三种干涉激光偏振态,利用实时光栅衍射效率测定和原子力显微镜观察等方法,考察了偶氮无定形分子玻璃(IAC-4)膜表面起伏光栅的形成速率和起伏深度。实验发现,当IAC-4形成表面起伏光栅时,其衍射效率增加速度和表面起伏光栅的深度为RCP+LCP>p+s>p+p。在RCP+LCP干涉激光照射下,IAC-4能够极快地形成表面起伏光栅;而用p+p干涉激光照射,则效率最低。在单束激光强度为58 mW/cm^2的RCP+LCP偏振态干涉激光照射下,经过80 s～2 min,一级衍射效率即可达62%并接近饱和,光栅起伏深度达到734 nm。而在同样强度的p+p,p+s偏振态干涉激光照射下,一级衍射效率和光栅起伏深度分别为3.1%,23 nm和9.3%,120 nm。采用p+s偏振干涉激光时,得到的光栅周期为干涉光场周期的一半。上述实验结果表明,偶氮无定形分子玻璃(IAC-4)材料可很好地用于表面起伏光栅制备,但刻写效果则取决于干涉激光的偏振态。Formation of surface-relief-gratings （SRGs） on amorphous azo glass films （IAC-4） was studied by using two interfering Ar^＋ laser beams with p ＋ p, p ＋ s and RCP ＋ LCP polarizations to inscribe the gratings. The diffraction efficiencies and the surface modulation of SRGs are measured by real time grating diffraction efficiency detection method and atomic force microscope, which strongly depend on the polarizations of the writing beams and show an order of RCP＋ LCP〉p＋ s〉p＋ p. SRGs. can be rapidly inscribed on IAC-4 films with large surface modulations and high diffraction efficiencies when irradiated with RCP＋ LCP interfering beams. But the inscription was quite inefficient using p＋p interfering beams. When irradiated with p＋s polarization beams, formation of halfperiod gratings was observed. After irradiated with p＋ p, p＋ s or RCP＋ LCP interfering beams （58 mW/cm^2 per beam） for 80 s-2 min, the diffraction efficiencies and modulated depths of the photo-induced SRGs are 3.1% and 23 nm, 9.3% and 120 nm, 62% and 734 nm respectively. The results indicate that IAC-4 can be used as a competitive material for SRG applications, but the fabrication heavily relies on the light polarization conditions.

关 键 词：功能材料 偶氮分子玻璃 光诱导 表面起伏光栅 偏振态 偶氮化合物 

分 类 号：O64[理学—物理化学]