红外AOTF调谐关系及其衍射光波长特性研究

对红外AOTF的分光原理和两级衍射光波长特性进行了理论与实验分析.结果表明:AOTF的驱动频率与衍射光波数基本成线性关系;入射角小于57.6°时,两级衍射光波长不等,波长差随驱动频率的增加而减小.分析了影响AOTF分辨率的主要因素,提出了改进方法.     

红外可调声光滤光器的设计和特性分析

根据声光互作用原理，以TeO2晶体为互作用介质，选取互作用长度为28mm，设计制成近红外声光可调滤光器（AOTF），其衍射波长与超声频率存在对应关系。测试结果表明，该器件的工作波长范围为0.9-2.6μm，驱动频率为40－120MHz，光谱分辨力为7.268nm，6.957nm（对应波长分别为1.5μm，2.4μm）。     

一种以AOTF为核心的农药荧光检测系统

提出了一种将 AOTF 技术用于农药含量检测的荧光光谱系统。该系统分别采用以α-Quartz,TeO2 晶体作为声光介质的激发和发射色散元件 AOTF,以高压短弧氙灯为激发光源,利用光纤探测并传输荧光,由数据采集卡进行数据接收和 A/D 转换。该系统通过声光调制产生单色光,由超声射频的变化实现光谱扫描,没有机械调谐部件,故波长切换快、结构简单。西维因农药的荧光特性测量结果表明,系统的荧光波长范围为 500-750nm, 光谱分辨率为 10nm。当激发光波长为320nm,荧光波长为 647nm,西维因溶液浓度为 0.0-120.0μg/L 时,系统具有较好的线性关系,线性相关系数 r 为 0.9991。它可用于对粮食作物中的农药残留的检测和荧光光谱分析。     

中红外AOTF前置光谱相机折/衍射混合变焦光学系统

设计了基于AOTF器件的中波红外光谱相机前置变焦系统,针对AOTF器件和探测器的特性,系统采用折/衍射混合设计,用6片透镜即实现了25~300 mm连续12×变焦,并用ZEMAX软件对则汇集结果进行优化和像质评价。结果表明,该光学系统各个波段上在空间频率14 lp/mm处调制传递函数(MTF)值接近衍射极限,能量集中度大于90%。可用于大多情况下中红外光谱成像分析以及中红外的目标探测及识别。     

基于AOTF的高光谱偏振成像系统设计

为获得目标和场景的偏振信息,提高目标识别和地物探测的准确度,设计了基于液晶相位可变延迟器(LCVR)和声光可调滤波器(AOTF)的高光谱偏振成像探测系统。首先介绍了偏振成像探测的原理,然后给出了探测系统的结构,并对其光学系统的各元件进行了合理的参数分配,最后利用编制的信息处理软件对系统采集的高光谱偏振图像进行了处理,处理结果能够反映出目标的光谱特性和偏振特性,对于复杂背景下的目标探测与识别具有重要的应用价值。     

一种新型农药浓度荧光测量系统的研究

根据声光可调滤波器（Acousto-Optic Tunable Filters，AOTF）的分光原理研制了一种新型的农药浓度荧光俭测系统，系统以高压短弧氙灯为激发光源，以AOTF为分光元件，利用光纤探测传输荧光，采用数据采集卡实现数据接收和A／D转换，由微机进行数据存储和显示，并且利用该系统实现了对西维因农药浓度的荧光持性的测量。结果表明：系统测量光谱范围为230nm～750nm，光谱分辨率为10nm，在激发波K319nm、荧光波长650nm、西维因溶液浓度为0．0～120．0μg／L时系统具有较好的线性关系，线性相关系数r为0．9991，该系统达到了荧光检测的指标。     

适用于微机电系统的自适应红外探测器的可调谐滤光器设计与开发

微机电系统与高品质红外探测技术联合运用为国防、商业、通信、生物医学检测及环境监测等许多应用领域面临的一系列具有挑战性的问题提供了唯一可行的解决方案．可调谐法布里．玻罗滤光片是适用于微机电系统的红外探测器的核心部件．滤光片的结构设计和关键结构件的材料对于滤光片的性能和整个装置的完善性有重要影响．阐述了利用有限元建模进行法布里-玻罗滤光片机械设计和分析的方法．报告了滤光片的结构材料——用低温等离子增强化学沉积法制造的氮化硅的结构表征和机械性能测定方法和结果．最后展示了一些所制作的滤光片阵列．     

基于可调谐二极管激光吸收光谱技术的炉内燃烧场参数在线监测系统设计

基于可调谐二极管激光吸收光谱(tunable diode laser absorption spectroscopy,TDLAS)技术,设计了炉内多燃烧场参数(温度,CO、CO₂和NO浓度等)同时在线监测技术方案,包括一维燃烧参数监测系统和多维燃烧参数监测系统。在一维燃烧参数监测系统中,引入光开关技术实现多个燃烧参数的同时测量。在二维燃烧参数监测系统中,引入分光器技术和代数迭代算法(algebraic reconstruction technique,ART)实现平面内二维燃烧参数的反演和测量。在此基础上,设计了三维燃烧参数监测系统,三维燃烧参数测量步骤为：先将炉内燃烧区域划分为多层二维切片;再基于ART法重建二维燃烧参数;最后基于多层二维燃烧参数数据重构三维燃烧参数。本文所设计的炉内燃烧场参数监测系统有利于未来锅炉精细化调整。     

Acousto-optic tunable filter chromatic aberration analysis and reduction with auto-focus system

An acousto-optic tunable filter (AOTF) displays optical band broadening and sidelobes as a result of the coupling between the acoustic wave and optical waves of different wavelengths. These features were analysed by wave-vector phase matching between the optical and acoustic waves. A crossed-line test board was imaged by an AOTF multi-spectral imaging system, showing image blurring in the direction of diffraction and image sharpness in the orthogonal direction produced by the greater bandwidth and sidelobes in the former direction. Applying the secondary-imaging principle and considering the wavelength-dependent refractive index, focal length varies over the broad wavelength range. An automatic focusing method is therefore proposed for use in AOTF multi-spectral imaging systems. A new method for image-sharpness evaluation, based on improved Structure Similarity Index Measurement (SSIM), is also proposed, based on the characteristics of the AOTF imaging system. Compared with the traditional gradient operator, as same as it, the new evaluation function realized the evaluation between different image quality, thus could achieve the automatic focusing for different multispectral images.     

Multiwavelength thermal lens spectrophotometer based on an acousto-optic tunable filter.

The instrumentation development of a novel, all solid-state, nonmoving parts, fast-scanning and wide-tuning range multiwavelength thermal lens spectrophotometer based on the acousto-optic tunable filter (AOTF) is described. Initially, the essential electronic driver was developed to facilitate the systematic characterization of the paratellurite (TeO2) AOTF and to demonstrate that this filter can be successfully and uniquely used as an all solid-state, nonmoving parts dispersive device to rapidly diffract white incident light into a selected color beam, to amplitude modulate the diffracted monochromatic light, and to keep its intensity constant. The multiwavelength thermal lens instrument was subsequently constructed using this AOTF, and preliminary results on advantages of this spectrophotometer such as its ability to characterize trace chemicals and to analyze multicomponent samples are delineated.     

Focal shift and extended focal depth with tunable pupil filter

Extended focal depth and focal shift are very important in microscopy, imaging and optical storage systems, and have attracted much attention in recent years. In order to obtain the extended focal depth and focal shift, a new kind of tunable pupil filter is proposed in this article. It consists of one half-wave plate between two quarter-wave plates, and the half-wave plate is made up of two zones that can rotate with respect to each other. By analyzing the intensity distribution in the focal region of the optical system with such a device, it reveals that focal shift can be realized by rotating any zone of the half-wave plate. When the phase difference of the two zones is π, the extended focal depth and transverse superresolution can be obtained at the same time. Therefore, it may be feasible to use such a tunable pupil filter in optical systems that need focal shift and extended focal depth.     

The accuracy of real-time computer spectrum analyzer calculations

A practical estimate of the accuracy of calculations of a software-hardware system consisting of an audio-frequency generator and a combined spectrum analyzer is presented. It is shown, using the example of a number of model measurements, that the frequency, amplitude, and phase errors of the calculations are very close to the theoretical limits. __________ Translated from Izmeritel’naya Tekhnika, No. 2, pp. 62–65, February, 2007.     

基于非线性介电薄膜的电调滤波器优化设计

采用脉冲激光沉积(PLD)法在(001)MgO基片上制备出高质量的SrTiO3(STO)薄膜,构建了Au/STO/MgO结构的叉指电容.在77K、10KHz条件下,对叉指电容的特性进行了测试,结果表明:在40kV/cm的直流电场作用下,电容值从1.75 pF减小为1.25 pF,电容值的相对变化率为28.5%.在此基础上,根据多层介质叉指电容保角变换模型.定量计算和仿真了STO薄膜的介电常数和微波频率下叉指电容的性能参数,并由此设计了一个三阶带通滤波器,该滤波器可实现13.50%的中心频率移动.     

内调制多色比色测温系统

发射率表征待测体与黑体的辐射强度之比,它与材料的性质、表面状态密切相关,随时间变化而变,并显著影响测温精度。为此提出了一种新的多色比色测温方法,该方法可以对待测体的发射率进行实时修正,具有自适应的特点,使测温仪可以快速、准确地测量温度。采用这种测温方法研制出新型的内调制多色比色测温系统,测温仪用内调制光电探测器作为探测单元,探测器能将恒定的光信号转变为交流电信号输出,便于信号放大和消噪,有效地提高了系统的信噪比。在1050～1650℃范围,测温最大误差为6．2‰。     

Wide wavelength range tunable guided-mode resonance filter based on incident angle rotation

A wide wavelength range tunable guided-mode resonance filter (GMRF) with high peak efficiencies, narrow linewidths, and low sidebands is experimentally demonstrated. The resonance wavelength can be tuned under TM polarized light illumination by rotating the angle of incidence. The GMRF composed of a one-dimensional grating layer and two waveguide layers on a glass substrate is designed with rigorous coupled-wave analysis. The grating structure of the GMRF is patterned by interference lithography with two ultraviolet laser beams. The reflection colours of fabricated GMRF can be shifted from blue to red by rotating the angle of incidence. The measured full width at half-maximums of the reflection peaks located at 450.6, 500.9, 551.0, 601.1, and 651.3?nm are 3.1, 3.9, 4.3, 3.8, and 4.1?nm, respectively. The corresponding sidebands of measured spectra are below 0.2. Compared with previous experimental studies on tunable structures, the narrow linewidths and low sidebands of the proposed GMRF are remarkably improved.     

基于单片机的拉力检测系统下位机的设计

详细阐述了以单片机为核心的拉力检测系统下位机的工作原理和硬软件设计方法 ,该系统可以记录、储存和设定瘫肢患者病人的肢力训练情况 ,使病人的康复诊疗过程精确量化和科学化 ,此检测系统可用于医院临床和家庭康复治疗     

基于互补式多波段带通滤光片的3D投影显示系统

本文提出一个基于互补式多波段带通滤光片的3D投影显示系统,该系统可以使观看者通过特制眼镜获得3D视觉体验。不同于时分复用和空分复用的3D显示系统,该系统借助成对的互补式滤光片实现谱分复用。通过设计可以实现两块滤光片的三对互补通带恰好分别覆盖RGB三色光谱范围,且每对互补通带相互交错几乎不重叠。在本文中,将两台普通的2D投影仪改造成3D投影系统,并测量了该系统的光谱、亮度、串扰等参数,其平均串扰3%,满足3D显示串扰小于10%的基本要求。