Photodichroic crystals for coherent optical data processing

The use of photodichroic alkali halide crystals as re-usable input, storage, and filter plane elements in a coherent optical computer are reviewed. Various recording methods and applications are presented with emphasis on the use of the M and M_A centres in NaF at room temperature.     

衍射光学元件检测及数据处理

衍射光学元件以其优异的光学性能,能够调制出理想的波面,较球面、非球面光学系统在校正色差方面具有较大优势。衍射光学元件的加工难点在于其加工精度不仅要求非球面基底的面形满足精度要求,还需要衍射结构的相位突变点及高度满足要求。由于其面形非连续性,存在相位突变点,传统的检测方式难于满足要求。对轮廓仪检测误差来源进行分析,结合检测数据分析加工误差数据,在此基础上进行数据处理,并将该方法获得的误差数据应用于零件加工,实现口径120 mm衍射面加工面形误差为0.539 μm。     

Some trends in microscope image processing

The present review tries to identify some trends among the multitude of ways followed by image processing developments in the field of microscopy. Nine topics were selected. They cover the fields of: signal processing, statistical analysis, artificial intelligence, three-dimensional microscopy, multidimensional microscopy, multimodality microscopy, theory, simulation and multidisciplinarity. A specific topic is dedicated to a trend towards semi-automation instead of full automation in image processing.     

Recent advances in optical bistability

In this paper, recent advances in optical bistability and gating of semiconductors will be reviewed. Nonlinear mechanisms responsible for switching will be described. The advantages of nonlinear etalons for massive parallelism and current problems in performing such operations will be mentioned.     

光学密码术最新进展

在总结基于耦合半导体激光器光学混沌的产生和同步原理的基础上,讨论了其在光学密码术中的应用,提出了基于混沌载波的数字加密基本方案和改进方案,包括混沌掩膜法（CM）和混沌键控法（CSK）。最后,给出了混沌加密传输技术的一些最新进展,如相位调制（PM）、自由空间光学链路（FSOL）、多激光器和多用户方案等。     

Solar optical processing

We will show that a white-light processor can be easily implemented with natural solar light for optical signal processing. The basic advantage of the solar optical processing is that the processing system does not require to carry an artificial light source, which is very suitable for spaceborne optical processing application. In addition to the simplicity, versatility, polychromaticity, and noise immunity of the white-light processing system, the solar processor is very durable and the operation is very cost effective. Several elementary experimental demonstrations obtained with the solar light processing are given.     

Non-coherent optical processing

The basic principles of non-coherent optical processing are first described. These include the diffuse source, redundancy, and parallel processing. The techniques of temporal and spatial modulation to overcome the inevitable dc bias are next described. A final section on applications gives a wide but not exhaustive range of examples.     

Photon echoes in molecular iodine vapors and nanofilms as a method of optical data processing

Properties and parameters of the photon echoes (PEs) used in optical data processing are analyzed. Physical methods for constructing functional processors and measuring devices on the basis of PE are proposed. Experiments on detecting femtosecond PEs in inorganic nanofilms at the room temperature are described.     

Recent progress in tissue optical clearing

Tissue optical clearing technique provides a prospective solution for the application of advanced optical methods in life sciences. This paper gives a review of recent developments in tissue optical clearing techniques. The physical, molecular and physiological mechanisms of tissue optical clearing are overviewed and discussed. Various methods for enhancing penetration of optical‐clearing agents into tissue, such as physical methods, chemical‐penetration enhancers and combination of physical and chemical methods are introduced. Combining the tissue optical clearing technique with advanced microscopy image or labeling technique, applications for 3D microstructure of whole tissues such as brain and central nervous system with unprecedented resolution are demonstrated. Moreover, the difference in diffusion and/or clearing ability of selected agents in healthy versus pathological tissues can provide a highly sensitive indicator of the tissue health/pathology condition. Finally, recent advances in optical clearing of soft or hard tissue for in vivo imaging and phototherapy are introduced.     

Recent trends in the local area network industry

Dual standards acceptance and industry consolidation through an increased number of mergers, acquisitions, and joint ventures are among the recent changes that have had an impact on the local area network (LAN) industry. The article highlights the industry changes that will affect both end-users and vendors of LANs.     

High pressures: Recent trends in materials science

Abstract

Pressure was developed during the 20th century. The most important illustration of the use of high pressure in Materials Science was the synthesis of diamond at the beginning of the fifties.

This contribution will describe the main scientific research axis developed these last years and based on high pressure (synthesis of new materials, stabilization of specific structures, crystal-growth, preparation of finely divided materials…).

In parallel some industrial developments will be analyzed.

In conclusion, the potential of high pressure will be sketched for the near future.     

Quantum information processing in optical images

Optical images can be used to transport, store and process information in a parallel way. We discuss different results obtained in the domain of ‘quantum imaging’, aiming at exploiting at the same time the quantum properties of optical images and their intrinsic parallelism. We define the notion of standard quantum limit (SQL) in optical resolution, set by the quantum noise of usual coherent light, and show that it can be much lower than the diffraction limit. We also prove that this limit can be circumvented by especially designed nonclassical and multimode light. We present an experiment showing that OPOs oscillating inside an exactly confocal cavity actually produce such transverse multimode nonclassical light. We finally describe another experiment which has surpassed the SQL in the case of beam positioning, both in the 1D and 2D cases.     

High-speed optical signal processing using semiconductor optical amplifiers

The authors report on all-optical switching devices based on semiconductor optical amplifiers (SOA) in applications for optical time division multiplexing (OTDM) transmission technology. The report includes a discussion on the basic properties of an SOA, on the nonlinear processes of cross-phase modulation and four-wave mixing in the SOA used for all-optical switching, and on the application of the SOA as demultiplexer, add-drop multiplexer, clock recovery and wavelength converter. The devices considered here operate at data rates in excess of \Gb80, where electrical signal processing is not available today.     

Recent advances in black phosphorus-based optical sensors

Abstract

Black phosphorus (BP), one of new ultrathin two-dimensional (2D) materials, has drawn considerable attention in various applications such as in gas sensing, photoelectric devices, cancer therapy, drug deliver and so on. Owing to its unique structure, excellent optical and electronic properties and good biocompatibility, BP in the field of optical sensors is a rising star and has been intensively investigated in the recent years. In this mini-review, we aim to describe recent development of BP-based optical sensors including colorimetric, fluorescent, electrogenerated chemiluminescent and chemiluminescent sensors.

     

近场光镊技术研究新进展

光镊技术,又称光学捕获技术,它是利用光的辐射压力来捕获和操纵包括电介质颗粒、生物细胞及生物大分子在内的微小粒子的。近场光镊技术利用近场光学倏逝场随距离急剧衰减的特征,可显著地降低捕获粒子的尺寸,实现纳米捕获。追踪了近场光镊技术的最新进展,包括全内反射相干倏逝场、近场光学镀膜光纤探针尖、激光照明金属探针尖和聚焦倏逝场用于近场光学捕获,并对其进行了比较,分析了它们存在的主要问题和未来发展方向。     

Review of coherent optical processing

The use of laser light to perform linear and nonlinear computational operations is reviewed. On linear operations, we discuss schemes involving gratings, computer holograms and optical feedback for addition, subtraction, differentiation, generalized orthogonal transformations and feedback operations. The important methods for implementing the spatial filters and for real-time processing are then briefly described. On nonlinear operations, we discuss technique involving ϕ-modulation, half-tone-screen processes, and nonlinear optical elements with and without coherent feedback for logarithm and thresholding operations. The state-of-the-art of optical processing research and its application areas are then considered at the end. The research was supported by the National Aeronautic and Space Administration and the National Science Foundation. A portion of this paper was presented at the Third Conference on the Laser, April 22–25, 1975, in New York. The Conference was sponsored by the New York Academy of Sciences.     

Planar holographic optical processing devices

Time-domain optical processing implemented through linear spectral filtering offers unique potential for future high-bandwidth communications systems. One key to realization of this potential is the development of robust, cost-effective, fully integrated filtering devices. A new spectral filtering device concept, derived from the unique properties of index holograms stamped or otherwise written in thin planar waveguide slabs, is described. The holograms that are described provide for high-resolution spectral filtering while at the same time mapping general input spatial waveforms to desired output waveforms.