非球面大孔径固体—液体复合声透镜及其水下成象应用的研究

本文介绍一种水下聚焦声成象用的、孔径为３００毫米的非球面固体－液体二元声透镜的设计和结构工艺特点。给出了最佳面形方程和象差计算曲线。运用声学理论，推导了透镜效率的计算公式，算得１兆赫时效率为８％。另外，推导了使用声透镜的水下聚焦声成象系统的观察距离的计算公式，并给出了系统的观察距离的计算曲线。 在４米长的水池中进行的聚焦声成象系统的实验中，声透镜成功地获得了水下物体的满意的反射声象和透射声象。透镜的角分辨率达０．６°。实验表明，此种型式的声透镜可作为水下显示系统的空间处理器。     

旋转圆弧式声透镜及其超声诊断技能器横向分辨率

为了改善机械扇形扫描医用超声脉冲回声成像装置的横向分辨率，在提高换能器的全程横向分辨率方面，使用旋转圆弧式声透镜，把活塞源的近场平面波声场，变换成一个等效圆环源的远场指向性的声场，是一种行之有效的方法。     

柱面型声透镜设计及验证

介绍了声透镜波束形成的基本原理和分析方法,分析了柱面型声透镜的设计方法。用ZEMAX光学软件设计并用ABS塑料制作了一个组合声透镜,在水池中完成其多个参数的测量。在频率500kHz和20°的视场范围内该声透镜的角度分辨率为l°。实验结果表明,该声透镜系统的波束宽度、旁瓣高度和视场范围均达到了设计要求．并很好的验证了柱面型声透镜的聚焦性能。     

湿法制作连续微透镜列阵新方法

制作连续微透镜列阵中主要的问题就是浮雕的深度和浮雕面形的控制,已有的微透镜列阵制作方法不能很好地解决;本文提出了一种利用干法和湿法蚀刻结合在硅片上制作连续深浮雕微透镜列阵的新方法,得到了深度４０μｍ的微柱面和旋转抛物面微透镜列阵。     

高光谱分辨率近红外CO2成像光谱仪设计与模拟

为满足大气CO2吸收光谱测量的要求,基于成像光谱仪基本工作原理和光学设计理论,设计了一种近红外CO2吸收光谱高光谱分辨率成像光谱仪.它采用简单平面反射光栅光谱仪结构,由入缝、两片聚焦透镜、平面反射光栅及两片成像透镜组成.透镜材料为普通常用光学玻璃,为减化系统结构透镜采用了二次非球面设计.采用ZEMAX软件对近红外光谱仪的光学系统进行了优化设计与模拟分析.最终设计与模拟分析结果表明,该光学系统光谱范围为1 591～1 621 nm,分辨率＜0.08 nm,F数为1.8,满足设计要求.     

一种用于经纬仪的实时检焦系统

为了使经纬仪进行实时自动检调焦，提出了一种双分离透镜法检焦系统，该方法利用目标自身的反射光，经双分离透镜将通过镜头后的光路分割成两束，通过检测目标在CCD上成像光斑位置的偏移量进行调焦，对具有一定亮度的目标能理想的自动对焦，自身不需发射系统，耗能少，结构紧凑；利用相关法进行数据处理和拟合，提高了检焦系统的分辨率。实验结果表明，此方法的检焦分辨率在0．1～0．15mm范围之内，检焦精度基本满足经纬仪第一像面焦深范围之内的要求，并具有调整方便以及实时性等优点。     

液体透镜将引导一场光学镜头革命

2008年3月,法国Varioptic公司宣布从2008年第3季度起将量产液体透镜,月产量预计为50万套.所生产的液体透镜将用于分辨率达500万像素的小型相机模块.这标志着液体透镜技术在经过多年的研发之后,即将正式进入大批量生产阶段.     

高分辨率钼/硅纳米多层膜TOF-SIMS和Pulsed-RF-GDOES深度谱的定量分析

飞行时间二次离子质谱（TOF-SIMS）和脉冲射频辉光放电发射光谱（Pulsed-RF-GDOES）是两种重要的深度剖析技术，前者广泛应用于半导体工业的质量控制，后者主要应用于工业涂层及表面氧（氮）化层的分析。Mo/Si纳米多层膜由于其出色的反射特性被广泛应用于纳米光刻、极紫外显微镜等领域。本文利用原子混合-粗糙度-信息深度（MRI）模型分辨率函数，通过卷积及反卷积方法分别对Mo(3.5nm)/Si(3.5nm)多层膜的TOF-SIMS和Pulsed-RF-GDOES深度谱数据进行了定量分析，获得了相应的膜层结构、膜层间界面粗糙度及深度分辨率等信息。结果表明：GDOES深度剖析产生了较大的溅射诱导粗糙度，SIMS的深度分辨率优于GDOES。     

飞秒激光双光子微细并行加工方法

飞秒激光三维微细加工技术具有真三维的制作能力和亚微米的加工分辨率等特点，因此获得越来越多的关注，但其串行工艺加工效率低是其技术难点．为了提高加工效率，搭建了一套飞秒激光并行加工平台，利用微透镜阵列实现飞秒激光分束聚焦，初步实现了双光子微细并行加工，在光敏树脂和玻璃上分别并行加工出多个二维结构，加工单点分辨率达到1．25μm．针对实验结果，对实验的加工一致性和分辨率进行分析，提出了进一步提高加工效率和加工一致性的方法．     

新型高亮度、高分辨率双束电子光学系统

由三基色显示管投影来实现大屏幕显示仍是首选方案，为了提高投影质量，缓解亮度与分辨率间的矛盾，采取了三项主要措施：1、采用双束扫描荧光屏；2、在发射系统采用层流枪的优点；3、采用电阻螺旋线形成的多极透镜与外磁透镜相配合作为主聚焦结构。     

Three-dimensional sensing based on a dynamically focused laser optical feedback imaging technique

A new method analogous to three-dimensional confocally based sensing is proposed. This method uses the technique of laser optical feedback imaging, which takes advantage of the resonant sensitivity of a short-cavity laser to frequency-shifted optical feedback for highly sensitive detection, making it ideal for surface and volume measurements of noncooperative targets. Rapid depth scanning is made possible by use of an electrically controlled variable-focus lens. The system is able to detect height discontinuities, and because detection occurs along the axis of projection the system does not have problems of shadow. Preliminary results for a depth range of 15 mm and a resolution of 100 mum are presented.     

Distributed Brillouin sensor system based on offset locking of two distributed feedback lasers

An offset locking technique, which uses an external optical delay line to tune the distributed feedback (DFB) laser frequency and a proportional-integral-derivative (PID) controller to lock the tuned frequency, is proposed for the first time, to the best of our knowledge, in the distributed Brillouin sensor system. This method provides large tuning range (greater than 1 GHz), high tuning speed (less than 100 mus per frequency step), and frequency tuning is independent of the laser frequency and power. The two DFB lasers are phase locked at the Brillouin frequency using a hardware PID controller. Using this offset locking with optical delay line, we demonstrated a high signal-to-noise ratio of 32 dB, which allows 1 m spatial resolution and better than 0.6 MHz frequency measurement accuracy (equivalent to 0.5 degrees C temperature resolution or 8 microepsilon strain resolution) over kilometers sensing length. The bias of the electro-optic modulator is controlled by a lock-in amplifier to provide high temperature or strain measurement accuracy.     

采用DBR LD的正弦相位调制激光干涉仪

分析影响正弦相位调制半导体激光干涉仪测量精度和系统分辨力的因素,提出了用分布布拉格反射半导体激光器DBR LD实现高分辨力亚纳米精度测量的方案。理论计算表明,DBR LD的波长连续调制深度比F-P腔LD高一个量级。指出邮于DBR LD的特殊结构可通过简单的反馈回路稳定输出光功率,有效地避免了光强波动对测量精度提高的限制。     

WDM与OTDR结合的弱光栅分布式温度传感网络

提出一种基于弱反射布拉格光栅的新型分布式温度传感网络,将WDM与OTDR相结合,采用WDM技术提高光栅的复用容量,利用OTDR对各个弱光栅进行实时检测,以实现光栅的密集串行复用,并提高空间分辨率。使用可调谐脉冲激光为光源,多组不同中心波长弱光栅等间距刻制在一根光纤上。利用一根光纤刻制的三组反射率为3%,中心波长分别为1544.660nm、1545.802nm和1546.900nm的9个FBG进行了温度实验。实验结果表明,在5～80℃的温度范围内,FBG的中心波长随温度变化呈良好的线性,线性度达到99.6%以上,温度测量的分辨率最高达到0.11℃,空间分辨率可达2m。     

基于F-P标准具和Music算法的FBG动态应变传感系统

提出了基于可调光纤环形激光器结构,并采用F-P标准具解调的光纤布拉格光栅(FBG)动态应变传感系统,具有高达60 dB的光学信噪比.F-P标准具用来作为一个边缘滤波器探测FBG波长的漂移,这样的解调方式具有稳定性高的优点.为了提高动态应变测量系统的分辨率,采用了Music算法进行频谱分析.实验结果显示,在700Hz时的动态应变分辨率达到了0.1με/Hz~(1/2),是传统FFT算法的10倍.     

CO2 laser-grooved long period fiber grating temperature sensor system based on intensity modulation

A long period fiber grating (LPFG) temperature sensor system based on intensity modulation is developed. The LPFG employed is fabricated by the use of a focused CO2 laser beam to carve periodic grooves on the fiber. The temperature measurement resolution of up to 0.1 degrees C has been obtained within the temperature range between 20 degrees C and 100 degrees C. The system uses a simple intensity measurement method and exhibits the advantages of convenient intensity measurement, double temperature sensitivity, high resolution, simple configuration, and low cost.     

太阳光下可调谐激光脉冲的波长和入射方向的实时测试和系统研究

提出了在恶劣环境条件下,应用衍射光栅测量宽波长范围可调谐脉冲激光波长和入射方向的实时测试方法,并设计了实验系统,在该实验系统中,光电传感器采用了ATMEL公司的50 MHz线阵探测器,由高速度数字信号处理器TMS320VC5509处理该传感器获得的信号,获得入射激光的波长和入射方向,实验结果表明,该系统能达到10ns的波长分辩率和1(°)的角度分辩率;该测试方法可用在相干探测激光告警接收机中.     

Three-dimensional laser microvision

A three-dimensional (3-D) optical imaging system offering high resolution in all three dimensions, requiring minimum manipulation and capable of real-time operation, is presented. The system derives its capabilities from use of the superstructure grating laser source in the implementation of a laser step frequency radar for depth information acquisition. A synthetic aperture radar technique was also used to further enhance its lateral resolution as well as extend the depth of focus. High-speed operation was made possible by a dual computer system consisting of a host and a remote microcomputer supported by a dual-channel Small Computer System Interface parallel data transfer system. The system is capable of operating near real time. The 3-D display of a tunneling diode, a microwave integrated circuit, and a see-through image taken by the system operating near real time are included. The depth resolution is 40 mum; lateral resolution with a synthetic aperture approach is a fraction of a micrometer and that without it is approximately 10 mum.     

Gated viewing laser imaging with compressive sensing

We present a prototype of gated viewing laser imaging with compressive sensing (GVLICS). By a new framework named compressive sensing, it is possible for us to perform laser imaging using a single-pixel detector where the transverse spatial resolution is obtained. Moreover, combining compressive sensing with gated viewing, the three-dimensional (3D) scene can be reconstructed by the time-slicing technique. The simulations are accomplished to evaluate the characteristics of the proposed GVLICS prototype. Qualitative analysis of Lissajous-type eye-pattern figures indicates that the range accuracy of the reconstructed 3D images is affected by the sampling rate, the image's noise, and the complexity of the scenes.     

Telecentric three-dimensional sensor with a liquid mirror for large-object inspection

We describe a device that applies the advantages of the space invariance of telecentric triangulation with the measurement of large objects (1 m(3)). Because the scan motion of the laser beam is decoupled from the physical transport of the sensor head, the fast scanning of large volumes becomes feasible. The device consists of a triangulation laser telemeter head that uses a large liquid primary mirror and an aspheric secondary mirror to realize the telecentric f-theta objective. We propose using liquid-mirror technology to make low-cost large objectives that have low f numbers, a diffraction-limited performance, and low scattering in the visible. This new optical system is useful for 3-D measurement. We discuss the optical configuration of the system and the performance of a laboratory prototype. The prototype has a standoff distance of 1.5 m, a telecentric scan as long as 1 m, a depth of view of 1 m, and a relative depth resolution of 0.5-1 mm.