液晶光学器件中液晶分子的转动由施加在ITO薄膜电极间的电场来控制,ITO晶体结构中空穴和自由电子与强激光的相互作用,使ITO薄膜电极成为液晶光学器件结构中激光损伤的薄弱环节。为探索ITO薄膜电极的激光损伤机制,使用原子力显微镜(AFM)对厚度约为10nm的ITO薄膜的表面形貌进行了测量。采用多重分形理论,定量分析了薄膜表面粗糙度及微孔洞分布情况,对薄膜在脉冲宽度为10ns,能量分别为50mJ、100mJ、200mJ激光辐照下所获得薄膜的表面粗糙度分布情况进行比较分析,结果显示,随着激光功率的增加,多重分形谱的谱宽SymbolDA@SymbolaA@呈增大趋势,且△f为负值,表明ITO薄膜表面粗糙度增大并形成微孔洞缺陷。

The rotating of liquid crystal molecules is controlled by the electric field between the two surface of ITO film. Interacting of free electron and hole in the ITO crystal lattice with radiating laser make the ITO electrode of liquid crystal devices be most vulnerable part. AFM was used to investigate the mechanism of the laser damage on ITO. The surface patterns of ITO film with thickness of 10nm was measured and quantitative analysis with multi-fractal theory of roughness and distribution was introduced. Distribution of roughness of film radiated by 10ns pulsed laser at the energy of 50mJ、100mJ、200mJ was comparied.The result of analysis indicated that the width of spectrum SymbolDA@SymbolaA@ of multi-fractal exhibit tendency of increment with elevated power of laser and the △f is negative, that is, the roughness is increasing and micro-cavities has been formed.