Dammann光栅在光互连中的应用

本文将Ｄａｍｍａｎｎ光栅［１，２］应用于光互连，提出了用Ｄａｍｍａｎｎ光栅实现完全混洗的方法．一个２×２的Ｄａｍｍａｎｎ光栅与一个成像透镜的组合，具有与四焦点透镜类似的成像作用．像面上，像的位置与Ｄａｍｍａｎｎ光栅的位置有关，适当选择光栅的位置可以实现不同元素数目及不同元素密度的完全混洗．本文给出了有关的理论推导及实验结果．     

一种二元光学元件阵列微芯模的工艺设计研究

提出一种二元光学元件微型芯模的工艺设计方法,该方法利用了数字调制器件（DMD芯片）的空间光调制特性。首先通过编程设计出二元光学器件的相关软件,以实现菲涅耳透镜、达曼光栅、龙基光栅等各种矢量图形,经过14倍精缩光学系统,将由DMD芯片生成的二元光学器件图像成像在涂有光刻胶的基板上。经显影、定影和坚膜后,再利用电化学蚀刻,得到一种二元光学阵列的微芯模。这种二元光学的芯模制作方法可以方便、高效、低成本地用于制作微光学器件。     

Influence of laser mode on splitting beam illumination effect of Dammann grating

The influences of various laser modes on the splitting beam effect of Dammann grating are studied in theory and by numerical simulation. The results show that fundamental mode laser resembles plane wave while high order mode laser differs from plane wave in the splitting beam effect by Dammann grating. Therefore, the fundamental mode laser is more suitable to be the light source to improve the energy efficiency in far-distance image detecting systems, such as laser image ladar, which use Dammann grating in the ilhlmination svstem.     

Contribution to analysis of the reflection grating method

The reflection grating method is a special case of the well-known reflection moiré principle. Whereas this moiré effect is suitable for measurement of the slope and curvature of deformed object surfaces by superposition of at least two grating images, the same results can be determined using only one reflected grating image without moiré lines.Some fundamental relationships between grating lines, optical setup and the desired deformation are developed and compared with the simplifications that are known from the moiré principle. The theory is tested using a circular plate, uniformly loaded and clamped at the circumference.     

二元微透镜的位相平衡设计及叠加积分衍射分析

本文用位相平衡设计法设计了优化的二元光学微透镜，这是对Ｄａｍｍａｎｎ阶梯波带片设计方法的一种改进。文中用叠加积分作了二元微透镜的衍射分析，并与Ｄａｍｍａｎｎ法作了比较，计算结果说明本方法的衍射效率及象质都优于Ｄａｍｍａｎｎ法。且能设计更大相对口径（Ｄ／ｆ）。具有任意物象距的二元微透镜。     

A method to obtain pulse contrast on a single shot

A novel method for obtaining a single shot multi-point high dynamic range pulse contrast measurement is presented. We use Dammann gratings to generate multiple beamlets by division of amplitude on ultrashort laser pulses. The analysis results show that this method can achieve high dynamic range in pulse contrast measurement on a single shot by using photomultiplier tube （PMT） detectors and the long working distances to minimize cross talk between channels. Some distortion of pulse shape is also analyzed detailedly with the Dammann grating and its compensation grating, which may degrade the pulse contrast measurement in some degree by pulse stretching and spectrum clipping.     

Low divergent diffractive optical element for remote detection

The low divergent Dammann grating is researched for the potential applications in aerospace. A laserbeam writing system is developed for writing the low divergent Dammann grating. The uniformity and efficiency of the Dammann grating are presented in this letter. The novelty of this letter is to demonstrate a low-cost and effective method to fabricate low divergent Dammann grating.     

高衍射效率亚波长结构Dammann光栅的设计

传统的Dammann光栅是基于标量衍射理论设计的二值相位等光强分束器件，其衍射效率的典型值为80%左右.基于严格耦合波分析理论和遗传算法，提出了一种设计亚波长结构Dammann光栅的新方法，且该新型二值相位光栅具有较高的衍射效率.同时利用自编的仿真程序包设计了多个光栅，并分析了制作误差对其衍射效率和光强均匀性的影响.仿真结果表明，用该方法所设计的Dammann光栅的衍射效率超过92%.     

Circular Dammann grating

A circular Dammann grating that can produce circular equal intensities at various orders in the far field is described. A set of parameters such as order, circular number, uniformity, and diffraction efficiency has been defined to describe the novel diffractive phase elements. Numerical solutions of binary-phase (0, pi) circular Dammann gratings are given. The results of experiments with a four-order circular Dammann grating made by a lithographic technique are presented. This novel diffractive optical element should be highly interesting in a wide variety of practical applications.     

Multiple-image hiding in the Fresnel domain

To avoid additive cross-talk among multiple images, they are separated from each other and even from the host image in the hiding and the extraction process by locating them independently in the Fresnel domain with computer-generated double phase-only masks. Gray images and white-ground and black-ground binary images can be hidden in the system at the same time. The hiding capacity of the system as to these three types of multiple image has also been investigated using a cascaded iterative algorithm. The security and the multiplexing parameters of the system are analyzed as well.     

基于达曼光栅的动态光耦合器

提出了一种基于达曼光栅的动态光耦合器,通过控制装置中达曼光栅位移参量,可实现入射光束的分束或合束以及两者之间的动态转换。适当选择达曼光栅类型可实现任意N×M的动态光耦合。实验中以1550 nm光波长为例,对1×8达曼动态光耦合器进行测量,测得其实现光开关功能时插入损耗为0.43 dB,实现光分束功能时均匀性达到0.03,单路插入损耗均值为10.5 dB。该实验装置易于调节、体积小、能耗低,且关键元件达曼光栅制作工艺成熟,易于批量化生产。特别是在实现中大规模光交换阵列时,该方案就具有更明显的优越性,有实用意义。     

On-line beam diagnostics based on single-shot beam splitting phase retrieval

We propose a novel on-line beam diagnostic method based on single-shot beam splitting phase retrieval. The incident beam to be measured is diffracted into many replicas by a Dammann grating and then propagates through a weakly scattering phase plate with a known structure; the exiting beams propagate along their original direction and form an array of diffraction patterns on the detector plane. By applying the intensity of diffraction patterns into an iterative algorithm and calculating between the grating plane, weakly scattering plane, and detector plane, the complex field of the incident beam can be reconstructed rapidly; the feasibility of this method is verified experimentally with wavelengths of 1053 and 632.8 nm.     

Design of a circular Dammann grating

A novel circular Dammann grating is proposed to generate uniform-intensity impulse rings corresponding to different diffraction orders in the far field. The intensities of the rings are determined by the coefficients of the circular sine series decomposition of the grating function. The definition of diffraction efficiency and uniformity for this novel device are described. Numerical solutions of binary phase circular Dammann gratings are presented. A binary phase three-order circular Dammann grating of pi phase depth is fabricated by an e-beam direct writing technique and is experimentally demonstrated.     

误差扩散法设计用于惯性约束聚变驱动器的色分离光栅-光束采样光栅集成元件

针对多次曝光法制作集成衍射光学元件时存在的加工制作复杂,会引入较大的对位误差等问题,基于计算全息中的误差扩散编码原理及部分相干光成像理论,提出采用误差扩散编码方法来设计用于制作浮雕结构集成元件的编码掩模的新方法。给出了利用误差扩散法设计的色分离光栅-光束采样光栅(CSG-BSG)集成元件编码掩模,模拟计算了经部分相干成像系统后的空间像光强分布,并与理想的集成元件面形进行了比较。结果表明,校正后均方差为7.5%,体积偏差为10.2%。     

任意发光类型的多色光照明下光栅塔尔博特效应的研究

利用部分相干光理论对多色光源照明下光栅的菲涅耳衍射进行了理论分析,得到了适用于任意发光类型(脉冲或连续发光)的多色光源的衍射光强的一般公式,理论结果表明菲涅耳衍射区的平均衍射光强的形式只与光源的频谱分布有关,这对借助于连续发光光源来研究脉冲光源照明下光栅的塔尔博特效应以及用来确定脉冲光源的性能参量提供了有力的参考依据。此外,详细讨论了光源的频谱分布对光栅塔尔博特效应的影响并进行了相应的数值计算。实验中通过选用不同频率的激光分别照明光栅,拍摄到对应于不同频率的衍射光强分布图像,从而间接获得多色光同时照明光栅时总的衍射光强分布。实验结果表明,理论和实验符合较好。     

New theoretical and experimental results in fresnel optics with applications to matter-wave and X-ray interferometry

We present new methods and formulae for calculating the image amplitude and image spatial power spectral density produced by monochromatic point-source illumination of a finite (and/or infinite) periodic complex transmission grating. At specific finite-width resonances the image amplitude is seen to display periodic complex amplitude self-imaging of the grating, with interlaced alias images. The finite width grating resonances (as a function of spatial frequency) are broadened (from zero width) and displaced in frequency relative to those produced by an infinite grating, although the finite resonance width relative to illumination wavelength variation persists with infinite gratings. In the Fresnel domain the self images are generalizations of the Talbot and von Lau effects, while in the Fraunhofer to Fresnel transition domain, our formulae demonstrate the formation of these structures from Fraunhofer diffraction order side-lobes. Using these results, design criteria are provided for constructing lens-free three-grating interferometers with spatially diffuse illumination and detection. Such interferometers have a wide variety of applications for both X-rays and matter-waves, including a phase sensitive imaging device and/or narrow-band interference filter. For wavelengths in the Ångstrom to sub-Ångstrom range they feature high throughput and ease of fabrication. Experimental results using light with such an interferometer are presented. Our results conclusively demonstrate interference and image aliasing in such a device with spatially diffuse illumination and detection. The experiment is readily reproducible in any undergraduate physics laboratory.Work supported by ONR Grant N00014-90-J-1475, by the firm J. F. Clauser & Assoc., and (MWR) by a U.S. Dept. of Education Fellowship     

Incoherent holographic imaging through thin turbulent media

We introduce and experimentally demonstrate a new method of computing Fresnel holograms of a real-existing, three-dimensional (3-D) scene hidden behind a thin turbulent medium, and illuminated by incoherent white light. From each perspective point of view, we acquire multiple noisy speckled images through the medium vibrated mechanically. These images are fused together to yield a smoothed perspective projection of the hidden 3-D scene. All smoothed projections are processed to yield a Fresnel hologram of the hidden scene. The 3-D image reconstructed from the hologram is further improved by digital blind deconvolution of each of the 3-D image slices with its own estimated impulse response.     

光学元件阵列的衍射理论分析

从菲涅耳衍射理论出发,分析了光学元件阵列的衍射成像性质,求得了其点扩散函数。进一步分析了光学元件阵列的综合成像性质,得到了阵列能够成综合像的条件。由相同光学单元组成的阵列在按一定的规律排列时可以成综合像,但一般只在一对固定的共轭面上有理想的综合像,而并非对于任意位置的物均有相应的综合像。 关键词：     

Extending the detection range of optical vortices by Dammann vortex gratings

We report a 2D static binary phase Dammann vortex grating that combines the features of a conventional vortex grating and a Dammann grating. This grating uniformly distributes energies among the diffraction orders, so the low-efficiency problem at higher diffraction orders of conventional vortex gratings is resolved and the detection range of the optical vortices (OVs) is greatly increased. Experimental results of OV detection using a fabricated 5×5 Dammann vortex grating are given, and the topological charge detection range from -12 to +12 is achieved. The potential applications of such gratings include transmitting, receiving, and multiplexing OV beams in optical communication systems.     

快速边界识别算法用于达曼光栅掩模数据生成的研究

针对达曼光栅的数据写入问题,提出了一种快速边界识别算法（FBIA）用于复杂二元光学图形掩模的CIF格式数据的生成。该算法首先识别出达曼光栅图形的边界点,然后按照左手原则对边界点进行排序并构成闭合曲线。针对闭合曲线中可能出现的“孤岛”,该算法可自动识别并依据其数量对图形重新分割取点。结果表明FBIA算法具有搜索快、效率高等优点,可广泛应用于各种二元位相型元件CIF格式掩模板数据的生成。