Analysis and Determination of Refractive Index Profiles of O^2＋ Ion-Implanted LiNbO3 Planar Waveguide Using Etching and Ellipsometry Techniques

The refractive index profiles of 3 MeV O^2＋ ion-implanted planar waveguides in lithium niobate are reconstructed based on etching and ellipsometry techniques. SRIM2003 code is used to simulate the damage distribution in waveguide. It is demonstrated that the index profile of this kind of waveguide, extending to several micrometres in depth, can be determined by etching in combination with following ellipsometric measurements. A good agreement is found between the simulated damage distributions in waveguide and the index profiles based on experimental data, and the width of refractive index barrier is wider than the result of SRIM2003.     

解题多反思 方法更自然

2011年高考湖南卷理科第21题是一道构思精巧、耐人寻味的解析几何问题:     

一道填空题的多角度思考

笔者在给学生答疑时遇到了这样一道填空题:过抛物线y2=2px(p>0)的焦点F作一条斜率大于0的直线l,与抛物线交于A、B两点.若在准线上存在点P,使△PAB是等边三角形,则直线l的斜率等于______.虽然这只是一道填空题,却别有趣味.经深入研究之后,笔者发现了一个有关抛物线的性质,并将其推广到了一般的圆锥曲线