A module for shaping control signals of the T0 detector of the ALICE experiment

An algorithm for synchronizing operation of the T0 start detector (ALICE experiment on the Large Hadron Collider) with an accelerator, a data reading system, and a laser detector testing system is described. The main functions and arrangement of the GRPG electronic module inserted additionally into the electronic support structure of the detector for shaping control signals are considered in detail.     

Multichannel control system for an acousto-optical modulator of laser radiation based on direct digital synthesis of frequencies

A module of control of an acousto-optical modulator of laser radiation in a multifrequency mode on the basis of a multichannel synthesizer with direct digital synthesis of frequencies is described. Specific features of system operation during multichannel laser recording with controlled amplitude, phase, and frequency of the channels with automatic calibration of intensity in each channel are considered. Application of the system in a photoplotter for producing photomasks of printed circuit boards makes it possible to increase the resolution of the device and to improve stability and reproducibility of recording.     

Evaluating sharpness functions for automated scanning electron microscopy

Fast and reliable autofocus techniques are an important topic for automated scanning electron microscopy. In this paper, different autofocus techniques are discussed and applied to a variety of experimental through-focus series of scanning electron microscopy images with different geometries. The procedure of quality evaluation is described, and for a variety of scanning electron microscope samples it is demonstrated that techniques based on image derivatives and Fourier transforms are in general better than statistical, intensity and histogram-based techniques. Further, it is shown that varying of an extra parameter can dramatically increase quality of an autofocus technique.     

光栅尺动态测量仪数据处理系统

主要介绍了光栅尺动态测量仪的数据采集和数据处理系统部分。该系统采用了软硬件相结合的方法,因而体积小、造价低、功能强、操作简便,且又在软件上注意了对激光波长的修正、被测光栅尺的修正及测试数据的平均处理,从而保证了仪器的总体精度。     

Suppression of side lobes in the fiber Bragg grating reflection spectrum

A revision of works on the methods of writing and apodization of fiber Bragg gratings (FBG) is presented. The possibilities of apodizing FBGs recorded by holographic methods with phase masks and Lloyd interferometer using laser radiation with a Gaussian intensity profile are considered. FBG reflection spectra are numerically simulated for different parameters of the writing beam and configurations of the experimental setup. Side-lobe suppression and FBG spectrum smoothing are experimentally demonstrated. It is shown that this effect is due to equalization of the average value of the induced refractive index in the FBGs. FBG applications, in particular, as frequency selectors in fiber lasers (tunable, narrow-band, and multiwavelength) are described.     

Alignment of the writing beam with the diffractive structure rotation axis in synthesis of diffractive optical elements in a polar coordinate system

A method is developed to ensure precise alignment of the origin of a polar coordinate system in which the laser beam position is defined in writing diffractive optical elements with the optical workpiece rotation axis. This method is used to improve the accuracy of a circular laser writing system in writing large-scale diffractive optical elements in a polar coordinate system. Results of studying new algorithms of detection and correction of positioning errors of the circular laser writing system in the course of writing are reported.     

Region sampling for robust and rapid autofocus in microscope

This paper proposes a region sampling based autofocus method for rapid and robust autofocus in microscope. Image content and region size are considered in region sampling criteria. An intelligent search algorithm which employs quartering hill climbing search and golden section search is developed, in which rule‐based evaluation of sampled focusing regions is applied. Experimental results demonstrate that the proposed method can significantly improve the performance of image‐based autofocus. Microsc. Res. Tech. 78:382–390, 2015. © 2015 Wiley Periodicals, Inc.     

Dynamic correction of the laser beam coordinate in fabrication of large-sized diffractive elements for testing aspherical mirrors

This paper presents a method of improving the accuracy of a circular laser system in fabrication of large-diameter diffractive optical elements by means of a polar coordinate system and the results of their use. An algorithm for correcting positioning errors of a circular laser writing system developed at the Institute of Automation and Electrometry, SB RAS, is proposed and tested. Highprecision synthesized holograms fabricated by this method and the results of using these elements for testing the 6.5 m diameter aspheric mirror of the James Webb space telescope (JWST) are described..     

变频泵控马达调速系统单神经元自适应PID控制

针对大惯性负截变频泵控马达调速系统动态性能差的特点，提出了采用不必基于模型的单神经元自适应PID控制。介绍了单神经元自适应PID控制器的结构和算法。仿真结果表明，单神经元自适应PID控制器较常规PID控制器具有更快的响应特性和良好的动态特性，对模型失配和负载扰动表现出更强的适应性和鲁棒性，而且不论是在加速段、等速段还是减速段，都具有较好的跟踪效果。     

Laser output power stabilization for direct laser writing system by using an acousto-optic modulator

We present experimental results on the output power stabilization of an Ar(+) laser for a direct laser writing system (LWS). Instability of the laser output power in the LWS cause resolution fluctuations of being fabricated diffractive optical elements or computer-generated holograms. For the purpose of reducing the power fluctuations, we have constituted a feedback loop with an acousto-optic modulator, a photodetector, and a servo controller. In this system, we have achieved the stability of +/-0.20% for 12 min and the relative intensity noise level of 2.1 x 10(-7) Hz(-12) at 100 Hz. In addition, we applied our system to a 2 mW internal mirror He-Ne laser. As a consequence, we achieved the output power stability of +/-0.12% for 25 min.     

脉冲激光眼科治疗仪控制器设计

文章介绍了医用眼科激光治疗仪控制器的设计。采用半导体泵浦Nd:YAG激光器,激光器有脉冲、连续两种工作方式。工作于脉冲方式时,单片机定时器产生脉冲控制激光器的工作频率;控制器使用数模转换器产生电压信号,驱动功率控制模块来控制激光器的功率;使用彩色触控液晶模组设计人机界面,通过触控屏来选择工作方式和设置工作参数;对关键电路进行了分析说明,给出了程序设计流程图。     

Bilateral prediction and intersection calculation autofocus method for automated microscopy

In this paper, a bilateral prediction and intersection calculation autofocus method for automated microscopy, which obtains the in‐focus position by calculating the intersection of the predicted left and right focus measure curves located respectively in the left and right sides of the peak position of the focus measure curve, is proposed and performed. According to the autofocus method, the area including the peak position of the focus measure curve and its left and right neighbourhoods should be determined firstly, and the left and right neighbourhoods are considered as the left and right sampling areas. The left and right focus measure curves are predicted by appropriate predicting models according to the two sample sequences, which comprise the focus values by evaluating the sampled images in the left sampling area and right sampling area, respectively and their corresponding sampling positions. The intersection of the predicted left and right focus measure curves is calculated and can be considered as the in‐focus position. The autofocus can be realized by moving the focus plane of the microscope to the intersection of the predicted left and right focus measure curves. The proposed bilateral prediction and intersection calculation autofocus method is experimentally verified in an automated light microscopy for implementing microassembly and micromanipulation. The theoretical analyses have shown that the proposed bilateral prediction and intersection calculation autofocus method can not only effectively avoid the principle error caused by assuming the symmetrical focus measure curve in the autofocus methods based on curve fitting, but also eliminate the possible waver search near the peak position in the modified fast climbing servo method. The experimental results have shown that the proposed bilateral prediction and intersection calculation autofocus method possesses the merits as follows: (1) the focusing accuracy is high and slightly affected by the sampling step size and (2) the focusing speed is higher than those of the 7‐point hill‐climbing search method and the quadratic curve fitting method with a determinate focusing accuracy.     

光学显微镜自动聚焦的技术研究

在对普通光学显微镜进行一定改装的基础之上 ,设计了一套显微镜自动聚焦系统 ,并且给出了图像的灰度差分绝对值之和算子 ,解决了自动聚焦过程中是否正确聚焦的判断问题。最后还给出了一套基于启发式搜索算法的聚焦搜索策略 ,以加快焦平面的搜索。     

Binary Laser Direct Writing System and Its Applications

A new laser direct writing system is introduced and the potential application of the diffractive optical elements (DOE‘ s) fabricated by applying laser direct writing system are presented. The fabrication techniques by applying the laser direct writing are developed. Experimental results have been obtained by applying laser direct writing machine with line width of 5μm and 10μm.     

Diffractive focusing fan-out element for the parallel DNA sequencer

Various issues of creation of diffractive optical elements transforming one laser beam with small divergence to a matrix of converging beams with a diffraction size of focused spots in the plane of object illumination and their application for problems of DNA sequencing and microscopy are considered. The parameters of diffractive elements are calculated and optimized in the approximation of the Fresnel–Kirchhoff diffraction theory. Diffractive elements are fabricated by the method of direct laser writing on a photoresist by using a circular laser writing system. Experimental characteristics of a diffractive element creating a matrix consisting of 33 × 33 beams, which are focused in one plane at a distance of 210 mm, are presented. The degree of nonuniformity of beam intensities determined by the ratio of beam intensities in the central region to intensities of peripheral beams is 1/2.5, which is potentially sufficient to be used in DNA sequencing problems. The maximum distortions of spot positions in the entire focusing field is <0.15%.     

Laser Technologies in Micro-Optics. Part 2. Fabrication of Elements with a Three-Dimensional Profile

Recent research in the field of formation of a 3D profile of optical elements with the use of direct laser writing at various wavelengths and photolithographic technologies on the basis of photomasks fabricated by means of laser writing is reviewed. Typical characteristics of the relief, as well as advantages and drawbacks of the above-mentioned methods are considered.     

直角坐标激光直写的动态曝光模型

在兼顾胶层的光吸收特性、直写光束的高斯分布特征以及直写光束与胶层相对运动的情况下,建立了直角坐标激光直写的动态曝光模型以有效预测线条的线宽和侧壁角.仿真实验表明:以恒值高斯光强曝光时,该模型与等效仿真条件下的Dill曝光模型仿真结果完全一致.进一步证明了该模型的有效性和正确性,解决了目前在激光直写中存在的只能预测线宽或在忽略光刻胶吸收作用的情况下粗略估计直写线条轮廓的问题.同时,基于该模型分别分析了直写光功率和直写速度对线条轮廓的影响机理,为优化激光直写工艺的加工参量提供了一种有效的分析途径.     

激光直写系统焦斑整形的研究

针对激光直写光刻系统设计整形衍射光学元件(DOE),对写入焦斑的整形进行了研究。提出对不同焦距写入物镜下的焦斑,利用同一个DOE加以整形的方法。模拟表明:整形后焦斑的面形和边缘显著改善,衍射效率高于实用指标,提供一种改善系统分辨能力的有效途径。     

热连轧机优化剪切系统介绍

对国内某钢厂热连轧机飞剪进行技术改进,实现剪切的最优化。该优化剪切系统集成测宽仪、激光测速仪、扫描式热金属探测器及优化剪切控制装置,实现对带钢中间坯剪切的最优化控制,确保精轧机组的良好穿带并实现热轧过程中的剪切最少化。     

城市路灯智能监控管理系统研究

针对目前城市中路灯数量众多、布置分散、运行管理困难和没有通信功能的特点,研制一种用无线通信和电力线载波通信相结合的城市路灯智能监控管理系统。中央控制室和路段控制器之间采用无线通信,路段控制器与单灯控制器之间采用电力线载波通信。介绍了系统的主要功能、结构原理,并且给出了控制器的详细软硬件设计,采用模块化设计思想,结构简单、功能实用、可靠性高,符合现代路灯监控自动化的需要。