Zero-mode waveguides have become important tools for the detection of single molecules. There are still, however, serious challenges because large molecules need to be packed into nano-holes. To circumvent this problem, we investigate and numerically simulate a novel planar sub-wavelength 3-dimension (3D) structure, which is named as near-field spot. It enables the detection of a single molecule in highly concentrated solutions. The near-field spot can produce evanescent waves at the dielectric/water interface, which exponentially decay as they travel away from the dielectric/water interface. These evanescent waves are keys for the detection of fluorescently tagged single molecules. A numerical simulation of the proposed device shows that the performance is comparable with a zero-mode waveguide. Additional degrees-of-freedom, however, can potentially supersede its performance.

采用离子源辅助电子束蒸发的方法，制备了以Si为基底，以TiO2为缓冲层的ZnO薄膜。通过进一步保温处理，在不同温度条件下进行退火处理得到了不同的样品薄膜，用于表面形貌分析和光散射特性实验研究。结果表明，退火温度对样品表面粗糙度、晶粒大小、分形维数等参数具有显著的影响，通过表面形貌分析有助于更好地理解薄膜晶粒生长机制和改进薄膜制备工艺；不同薄膜样品的反射光强度和偏振度对不同偏振光具有不同的角度响应特征，且与薄膜表面统计特性具有一定的关联性，薄膜的光散射特性研究对研究弱散射随机粗糙表面的退偏作用具有一定的参考价值。

A concave two-dimensional (2D) photonic crystal waveguide (PCW) with corrugated surface is theoretically used as a focusing structure. To design this structure, a genetic algorithm is combined with the finite-difference time-domain method. For PCWs with different degrees of concaveness, the power reaches about 80% at different focusing points when the morphology of the concave surface is optimized. More importantly, the focusing location is easily controlled by changing the location of the detector placed in the output field.

利用二维光子晶体的自准直和定向耦合效应设计了一种由一个自准直区域、耦合区和两个周期性介质波导组成分束器, 利用平面波展开法从理论上研究了耦合区的色散关系, 计算得到了耦合长度, 同时使用时域有限差分方法模拟了电磁波在其中的传输特性, 得到了稳态的电场分布, 讨论了光波从自准直区域到光子晶体波导高效耦合的技术。结果表明：在相位匹配条件下, 从自准直区域传播到耦合区域的的电磁波可以有效的分束到两个周期性介质波导中, 同时能够弯曲任意角度, 而且透射率保持在90%以上。最后, 在设计的分束器基础上提出了一种增大点源和像点之间距离的方法。

采用了结构为(B′A′)N(A′B′)N (B′′A′′)N(A′′B′′)N的光子晶体异质结来设计一维全方向滤波器。利用传输矩阵法对该结构的透射性能进行了分析, 并结合遗传算法对该光子晶体异质内各组元厚度比和组元的周期数进行了优化, 最终得到一个相对较优的一维光子晶体滤波器。该滤波器具有较宽的滤波频带, 并且具有很好的方向选择特性, 是一种高精度的一维全方向光子晶体滤波器, 可广泛应用于滤波器、光开关等光通讯领域。

The depolarization behavior of backscattered linearly polarized light from ZnO thin film was investigated experimentally. The results show that the characteristics are related to both the polarization orientation and wavelength of linearly polarized incident light. When the incident light is s-polarized, the depolarization behaviors are different for different wavelengths. When the incident light is p-polarized, the depolarization behaviors, on the contrary, are similar for different wavelengths. In addition, there is an optimal incident angle for depolarization of linearly polarized light with different wavelengths, which is equal to their effective Brewster angles, respectively.