Pulse compression by filamentation in argon with an acoustic optical programmable dispersive filter for predispersion compensation

We have experimentally demonstrated pulses 0.4 mJ in duration smaller than 12 fs; with an excellent spatial beam profile by self-guided propagation in argon. The original 52 fs pulses from the chirped pulsed amplification laser system are first precompressed to 32 fs by inserting an acoustic optical programmable dispersive filter instrument into the laser system for spectrum reshaping and dispersion compensation, and the pulse spectrum is subsequently broadened by filamentation in an argon cell. By using chirped mirrors for post-dispersion compensation, the pulses are successfully compressed to smaller than 12 fs.

A low-cost CMOS programmable temperature

A novel uncalibrated CMOS programmable temperature switch with high temperature accuracy is presented. Its threshold temperature T-th can be programmed by adjusting the ratios of width and length of the transistors. The operating principles of the temperature switch circuit is theoretically explained. A floating gate neural MOS circuit is designed to compensate automatically the threshold temperature T-th variation that results form the process tolerance. The switch circuit is implemented in a standard 0.35 mu m CMOS process. The temperature switch can be programmed to perform the switch operation at 16 different threshold temperature T(th)s from 45-120 degrees C with a 5 degrees C increment. The measurement shows a good consistency in the threshold temperatures. The chip core area is 0.04 mm(2) and power consumption is 3.1 mu A at 3.3V power supply. The advantages of the temperature switch are low power consumption, the programmable threshold temperature and the controllable hysteresis.

A programmable SIMD vision chip for real-time vision applications

A programmable vision chip for real-time vision applications is presented. The chip architecture is a combination of a SIMD processing element array and row-parallel processors, which can perform pixel-parallel and row-parallel operations at high speed. It implements the mathematical morphology method to carry out low-level and mid-level image processing and sends out image features for high-level image processing without I/O bottleneck. The chip can perform many algorithms through software control. The simulated maximum frequency of the vision chip is 300 MHz with 16 x 16 pixels resolution. It achieves the rate of 1000 frames per second in real-time vision. A prototype chip with a 16 x 16 PE array is fabricated by the 0.18 mu m standard CMOS process. It has a pixel size of 30 mu m x 40 mu m and 8.72 mW power consumption with a 1.8 V power supply. Experiments including the mathematical morphology method and target tracking application demonstrated that the chip is fully functional and can be applied in real-time vision applications.

A 1,000 Frames/s Programmable Vision Chip with Variable Resolution and Row-Pixel-Mixed Parallel Image Processors

A programmable vision chip with variable resolution and row-pixel-mixed parallel image processors is presented. The chip consists of a CMOS sensor array, with row-parallel 6-bit Algorithmic ADCs, row-parallel gray-scale image processors, pixel-parallel SIMD Processing Element (PE) array, and instruction controller. The resolution of the image in the chip is variable: high resolution for a focused area and low resolution for general view. It implements gray-scale and binary mathematical morphology algorithms in series to carry out low-level and mid-level image processing and sends out features of the image for various applications. It can perform image processing at over 1,000 frames/s (fps). A prototype chip with 64 x 64 pixels resolution and 6-bit gray-scale image is fabricated in 0.18 mu m Standard CMOS process. The area size of chip is 1.5 mm x 3.5 mm. Each pixel size is 9.5 mu m x 9.5 mu m and each processing element size is 23 mu m x 29 mu m. The experiment results demonstrate that the chip can perform low-level and mid-level image processing and it can be applied in the real-time vision applications, such as high speed target tracking.

Pulse Compression by Filamentation in Argon with an Acoustic Optical Programmable Dispersive Filter for Predispersion Compensation

We have experimentally demonstrated pulses 0.4 mJ in duration smaller than 12 fs with an excellent spatial beam profile by self-guided propagation in argon. The original 52 fs pulses from the chirped pulsed amplification laser system are first precompressed to 32 fs by inserting an acoustic optical programmable dispersive filter instrument into the laser system for spectrum reshaping and dispersion compensation, and the pulse spectrum is subsequently broadened by filamentation in an argon cell. By using chirped mirrors for post-dispersion compensation, the pulses are successfully compressed to smaller than 12 fs.

基于Nios-Ⅱ用于加速器监控系统的通用型可重配置嵌入式微控制器

FPGA and dedicated micro-controller chips are widely used in HIRFL-CSR monitor and control systems.This paper discusses the characteristics of HIRFL-CSR s dedicated micro-controllers and it s requirement for micro-controllers. Using programmable technology and Nios-Ⅱ processor,we have designed and implemented a reconfigurable embedded micro(controller in altera cycloneⅡ2c35f484 FPGA. The micro-controller which has low hardware cost and 185 MHz maximum operating frequency can replace the dedicated micro-cont...中文文摘：讨论并参考了冷却储存环目前使用的专用微控制器的特点和其对微控制器的需求,采用可编程技术和Nios-Ⅱ处理器,在altera-cycloneII2c35f484芯片内实现可重构微控制器。该微控制器硬件资源消耗少,最大工作频率可达185MHz,可代替目前在监控系统中大量使用的专用微控制器芯片,减小硬件设计复杂度、节约成本。

Dendrimers as "controllers" for modulation of electrodeposited silver nanostructures

Electrodeposition of silver nanostructures on a polyamidoamine (PAMAM) dendrimers-modified surface has been reported. The assembled PAMAM monolayer film was used as a substrate for electrodeposition. We found that the PAMAM dendrimers obviously affected nucleation growth and silver nanostructures (spherical, dendritic and "fish bone" shapes) were obtained, which were different from those deposited on unmodified surfaces. It was attributed to the unique structures and properties of PAMAM dendrimers compared with linear polymers.

可重构机器人体系结构及模块化控制系统的实现

本文提出了一种适用于新型可重构星球机器人的模块化控制系统,根据机构和运动特性,基于CAN总线和分布式控制器技术,将系统结构和功能分解成不同模块由各自的控制器独立执行,建立具有任务层和运动层的分层次控制结构,实现了组合式规划、分布式控制的混合式控制方法。本文设计了两种不同的控制器,并采用PPG脉冲宽度调节方法实现了对在机器人上使用的R/C电机的标定和控制。通过在子机器人原理样机上进行实验,验证了这套控制系统和控制体系结构的可行性。

Active phase control and frequency chirp effects on supercontinuum generation in high birefringence photonic crystal fiber

An acoustic-optics programmable dispersive filter (AOPDF) was first employed to actively control the linearly polarized femtosecond pump pulse frequency chirp for supercontinuum (SC) generation in a high birefringence photonic crystal fiber (PCF). By accurately controlling the second order phase distortion and polarization direction of incident pulses, the output SC spectrum can be tuned to various spectral energy distributions and bandwidths. The pump pulse energy and bandwidth are preserved in our experiment. It is found that SC with broader bandwidth can be generated with positive chirped pump pulses except when the chirp value is larger than the optimal value, and the same optimal value exists for the pump pulses polarized along the two principal axes. With optimal positive chirp, more than 78% of the pump energy can be transferred to below 750 nm. Otherwise, negative chirp will weaken the blue-shift broadening and the SC bandwidth. (C) 2007 Elsevier B.V. All rights reserved.

Generation of 17-TW 23-fs pulses with a two-stage Ti : Sapphire amplifier at repetition rate 10 Hz

We have developed a two-stage Ti:sapphire amplifier system which can produce 17-TW/23-fs pulses at a repetition rate 10 MHz. A birefringent plate is used in the regenerative amplifier to alleviate gain narrowing, while an all-reflective cylindrical-mirror-based pulse stretcher and an acousto-optic programmable dispersive filter (AOPDF) are used to compensate for the higher order dispersion of the system.

Parasitic lasing suppression in high gain femtosecond petawatt Ti: sapphire amplifier

New parasitic lasing suppression techniques are developed and high gain amplification is demonstrated in a petawatt level Ti:sapphire amplifier based on the chirped pulse amplification (CPA) scheme. Cladding the large aperture Ti: sapphire with refractive-index matched liquid doped with absorber suppresses the transverse lasing. The acousto-optic programmable dispersive filter (AOPDF) is used to realize side-lobe suppression in the temporal profile of the compressed pulse. The 800 nm laser output with peak power of 0.89 PW and pulse width of 29.0 fs is demonstrated. (c) 2007 Optical Society of America.

适合于小飞机防撞系统的机载小型激光测距仪

报道了一种重量轻、功耗低、适合于小飞机防撞系统应用的小型激光测距仪。系统基于脉冲激光测距原理，采用905nm半导体脉冲激光器、电感升压式偏置高压电源和可编程逻辑器件（PLD），研制出重量不大于100g，功耗不大于625mW，测量范围100m，盲区3．0m，分辨率±1m的机载小型激光测距仪。实验测试结果表明，其各项技术性能指标符合无人驾驶小飞机防撞系统的应用要求。

星载激光测距仪的高精度时间间隔测量单元

高精度时间间隔测量单元(TIU)是星载激光测距仪的关键部件。基于现场可编程门阵列(FPGA)研制出了满足星载要求的高精度、高集成度时间间隔测量单元。该单元采用数字计数法结合数字延迟线插入法的技术,在0.5～10 km的测量距离范围内,时间分辨率为500 ps。通过地面检测,在全程范围内保持了良好的线性度,标准偏差小于270 ps。该单元同时具备测量脉冲回波宽度的能力,可以获取目标的脉冲展宽信息。由于单元选用的元器件都具有航天产品性能,因此其设计和技术指标可满足星载激光测距仪的应用。