一种抑制二倍频半波孔现象的短波通设计方法  

A New Approach to Eliminate Half-Wave Holes in Short-Wave Pass Filters with Layer Inhomogeneity

作　　者：鲍刚华[1,2] 焦宏飞[1,2] 程鑫彬[1,2] 刘华松[3] 王占山[1,2] 

机构地区：[1]先进微结构材料教育部重点实验室,上海200092 [2]同济大学精密光学工程技术研究所,上海200092 [3]天津市薄膜光学重点实验室天津津航技术物理研究所,天津300192

出　　处：《光学学报》2014年第8期327-332,共6页Acta Optica Sinica

基　　金：国家自然科学基金(61108036;61235011);中央高校基本科研业务费专项资金(1370219171);国家863计划

摘　　要：短波通滤色片是光学系统,尤其是激光系统中普遍使用的一种薄膜,它的基本结构为(0.5LH0.5L)N。但薄膜的非均质性会产生半波孔现象,从而影响滤色片的光学特性。利用导纳技术分析了折射率非均质性产生半波孔现象的原因:非均质性使常规膜系基本周期内导纳轨迹的终点偏离起点;这种偏离越大,半波孔现象就越严重。优化了常规膜系的基本周期结构,通过在高低折射率膜层之间引入导纳匹配层,使得改良后的基本周期导纳轨迹的终点与起点偏差大大减小,提高了半波处的透射率,从而提出了一种可以抑制由非均质性引起的半波孔现象的短波通设计方法,并依据实际制备工艺进行了误差分析。最终成功制备出了具有超宽透射带的短波通滤色片,实验和理论曲线具有很好的一致性。Short-wave pass filter is an important optical component in high power laser systems which has the repetitive structure of （0.5LH0.5L）N. But its optical property is significantly influenced by the half-wave hole due to layer inhomogeneity. Analysis by admittance theory shows the key reason for the presence of half-wave hole： the end point of the admittance locus of the periodic structure based on the quarter-wave stack doesn＇t return to the initial point again. The greater the deviation, the worse the half-wave hole. By inserting matching layers between high and low index materials, a new method is presented to eliminate half-wave hole. The new short-pass film is designed and successfully fabricated, which has a super wide and smooth region with low reflectance at around second harmonic. The experimental results consistent well with the theoretical performance.

关 键 词：薄膜 短波通滤色片 半波孔 导纳匹配 非均质性 

分 类 号：O436[机械工程—光学工程]