Design and Characterization of Novel Comb Filters Based on Periodical Fiber Bragg Gratings

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Design Method for Optical Waveguide Filters Having Corrugation Structures by Corrugation Width Modulation

A method to design a corrugated optical waveguide filter by modulating the corrugation width profile is proposed. This method is based on combined applications of the Fourier transformation and the F-matrix formalism. The method achieves the spatial profile of the corrugation width required to design a filter with any specified spectral profile of the reflection coefficient. The idea of the technique is that the spatial variation of the effective refractive index can be transformed, with the help of the F-matrix formalism, to variation of the corrugation width while maintaining a constant amplitude of the refractive index variation. Two examples are given applying the technique to the design of optical waveguide filters with reflectivity profiles of two- and four-rejection bands.     

横向位移双曝光散斑图维纳谱的信息分布

讨论了横向位移双曝光散斑图维纳谱的信息分布，并由此导出杨氏纹图的一般表达式。讨论了条纹可见度与应变，面内转动，照明光束直径与条纹图图空间坐标的关系，指出了在条纹可见度影响下最大可见条纹数目。还讨论了散斑衬比与衍射晕的关系。     

Design and performance of millimeter-wave end-coupled bandpass filters

The design and performance of millimeter-wave microstrip/suspended-stripline end-coupled bandpass filters are presented. Filters in Ka-band (26.5 to 40 GHz) and W-band (75 to 110 GHz) using suspended-stripline and microstrip have been designed. Good agreement between the experimental results and those predicted theoretically was observed. Measured passband insertion losses of less than 1 and 0.5 dB have been achieved in W- and Ka-band, respectively. An extremely wideband waveguide-to-microstrip transition with an insertion loss of 0.25 dB over the full W-band is also presented.     

Optical-digital processors for morphological and rank order filtering

Non-linear rank order and morphological filtering can be achieved in optical-digital processors. In these processors, all convolutions are performed in inherently parallel optical correlators. Arithmetic and logic operations are made digitally. Due to the threshold decomposition concept, grey scale images are sequentially treated slice by slice. The optical-digital method of local histogram calculation within both binary and weighted neighbourhoods allows local non-linear operations. We derive rank order and morphological filters from optically calculated convolutions. Several configurations of optical convolvers are discussed. Further improvements in the technology of spatial light modulators and encoded light sources are needed before these processors' practical uses will appear.     

用于高数值孔径物镜的可调光瞳滤波器

根据矢量衍射理论,提出了一种用于提高高数值孔径显微物镜纵向分辨率的可调二元环形光瞳滤波器,通过改变滤波器的环半径获得不同的纵向分辨率,并利用共焦显微术点扩散函数的乘积性大大地降低了旁瓣相对主瓣的比值。模拟结果表明,这种新型滤波器不仅可以提高高数值孔径物镜的纵向分辨率,同时基本上不影响横向分辨率。     

Solc型双折射滤波器离轴消光比的研究

提出了一种Solc型双折射滤波器的离轴消光比的一般性计算方法，利用所得结果模拟出了Solc型双折射滤波器的锥光干涉图以及发散光积分消光比与波长和发散角的关系曲线，实验结果证实了理论推算的合理性，此外本方法也适用于计算各种类型双折射滤波器的离轴消光比。     

A study of the optical transfer function for annular binary filters

The annular binary pupil filters consist of two transparent annuli obstructed by an annular mask. The optical transfer functions for them are analytically derived under paraxial approximation, and three- and two- as well as one-dimensional numerical plots are presented. It is shown that by changing the parameters of transparent regions it is possible to improve the axial resolution whilst the transverse resolution remains unchanged, compared with an annular lens. Results indicate, as is well known, that this kind of filters can be applied to three-dimensional confocal microscopy.     

Some of my favorite results with Endre Csáki and Pál Révész - A survey

Summary Some topics of our twenty some years of joint work is discussed. Just to name a few; joint behavior of the maximum of the Wiener process and its location, global and local almost sure limit theorems, strong approximation of the planar local time difference, a general Strassen type theorem, maximal local time on subsets.