张志三先生的生平

张志三,光谱学家。《光谱学与光谱分析》的副主编、顾问。早期致力于原子发射光谱应用的研究。建立较完善的分子光谱实验室,为我国光谱学的发展做出了贡献。热心进行激光光谱的应用研究,促进了我国激光物理,原子、分子物理的发展。张志三先生因病于2003年9月20日在北京逝世,享年83岁。张先生严以律己,宽厚待人,治学严谨的科学态度,深得科技界同行的爱戴和赞誉。得知张先生过世的消息,大家深为悲痛。张志三先生的生前好友于9月25日到医院向张先生作最后告别。     

多层光子晶体滤波器研究

从双层结构出发研究了一种由多块不同的单周期光子晶体组合而成的多层结构的滤波器，论述了这种滤波器的工作原理，研究表明这种结构适于制作带通、窄带通过、带阻、宽带带阻、高通以及其它各种性能的滤波器。实验和理论研究的结果相一致。     

Abnormal Modulation of Dielectric Band Transmittance of Polystyrene Opal

The abnormal transmittance in the dielectric band edge of a polystyrene opal is observed and analysed. The transmittance is periodically modulated and the period of modulation varies with the wavelength, which destroys the perfect structure of the photonic band gap. The transmittance modulation originates from the propagation of the low order whispering-gallery mode excited in polystyrene spheres. These results indicate that the whisperinggallery mode has a great influence on practical applications of polystyrene opal.     

Effect of the defect on the focusing in a two-dimensional photonic-crystal-based flat lens

We have investigated in detail the influence of defect on the focusing of electromagnetic waves in a two-dimensional photonic-crystal flat lens by using the finite-difference time-domain method. The result shows that many focusings can be observed at the symmetrical positions when a defect is introduced into the lens. Furthermore, the wave-guides in the lens can confine the transmission wave effectively and improve the quality of the focusing.     

用一种新光源的光谱学

引 言 科学的光谱学真正开始在瑞典的Uppsala,1853年A.Angstrom在那里获得了一个放电火花隙的某些谱线,它们分别来源于金属电极及电极之间的气体.J.Fraunhofer在此之前就记录了太阳光谱的暗线并测量了它们的波长.但是,Angstrom首先证认了其中一些谱线相应于火花隙中特殊物质所辐射的亮线.更重要的是,他得到了氢的红线,即Hα线.在以后的几年里,Angstrom在氢里又发现了几条可见区域的谱线并精确地测量了它们的波长.W.Huggins和H.W.Vogel在1880年成功地拍摄了恒星的光谱.他们发现这些可见区的谱线是一个扩展到紫外区域的更长的系列的一部…     

Negative Refraction and Near-Field Imaging of an Elliptical-Rod Photonic Crystal Slab in the Second Band

Negative refraction and imaging properties of the electromagnetic wave through a two-dimensional photonic crystal （PC） slab, which consists of a square lattice of elliptical dielectric rods immersed in the air background, is studied by the plane-wave expansion method and the finite-difference time-domain method. A point source placed in the vicinity of the PC slab can form a good-quality image spot through the PC slab for the incident frequencies within the second photonic band. The calculated result also shows that negative refraction occurs in this kind of PC slab.     

Transmission Properties of W3 Y-Branch Filters in Two-Dimensional Photonic Crystal Slabs

A highly efficient W3 Y-branch filter in a two-dimensional photonic crystal slab with triangular lattice of air holes is designed and fabricated, and its transmission properties are measured. By accurately adjusting the size of the resonant cavities, the minimum wavelength spacing of 7 nm between two channels is realized. The corresponding resonant wavelengths of the two cavities agree well with the calculated ones. This implies that this kind of fiIter may be promising in integrated wavelength division multiplexing system.     

Complete Band-Gap in Two-Dimensional Quasiperiod Photonic Crystals with Hollow Cylinders

The transmission properties of quasiperiodic photonic crystals (QPCs) based on the random square-triangle tiling system are investigated by the multiple scattering method. The hollow cylinders are introduced in our calculation. It is found that QPCs with hollow cylinders also possess a complete band gap common to s- and p-polarized waves when the inner radius of hollow cylinders is larger than a certain value. The QPCs possessing the complete band gap can be applied to the fields of light emitting, wave-guides, optical filters, high-Q resonators and antennas.     

Oscillatory disturbance in force calibration of optical tweezers

In the calibration of the optical trap stiffness, it is found that there appears an attenuating oscillation as an oscillatory disturbance added to the trapped bead movement, when the scanner is driven by a triangular wave input.An equivalent oscillator model is put forward to explain the mechanism of the oscillatory disturbance. Both the measurements and calculations show that the attenuating oscillation comes from the oscillation of the scanner and the triangular wave drive causes this additional oscillation of the scanner. Furthermore, the analysis indicates that the oscillatory disturbance will become stronger, when the stiffness of the trap increases or the natural frequency of the scanner decreases. We adopt another driving way, i.e. a sinusoidal wave input is used instead of the triangular wave input. Our experiment has verified that in this case the oscillatory disturbance is eliminated completely.     

用聚苯乙烯小球模拟生物组织中的光强分布

用水中周期排列的直径为3μm的单层聚苯乙烯小球以及单个聚苯乙烯小球模拟对光敏感的生物组织，如绿色植物叶肉细胞、动物皮肤的表皮细胞、苍蝇蜜蜂等的复眼以及一种海蛇尾背部的光敏器官的光强分布.通过观测聚苯乙烯小球在不同深度的光强分布，发现随着深度的改变其光强分布是截然不同的.在小球的横截面上，光强分布不很均匀而且呈有规律的花纹图案.在小球的外面，光强分布表现为独立的透镜成像分布.周期排列的小球与单个小球在其横截面上的光强分布也完全不同，前者的光强分布表现出球与球之间很大的相关性. 关键词： 生物组织 周期排列 光强分布