圆环孔阵列超材料对热释电太赫兹探测器性能影响关系研究

本文提出了新的基于圆环孔阵列超材料的钽酸锂热释电太赫兹探测器,以提高0.1—1 THz频段太赫兹波探测性能.仿真分析了内外径、周期、厚度等特征参数对圆环孔阵列超材料太赫兹波透射带宽及透射率的定量影响关系,阐明了圆环孔阵列超材料与热释电探测器的不同结合方式对探测器的带宽及噪声等效功率的作用机理;制备了两种圆环孔阵列超材料钽酸锂热释电太赫兹探测器;测试了圆环孔阵列超材料的透射特性和两类热释电探测器的噪声等效功率.结果表明,所制备的圆环孔阵列超材料在0.25—0.65 THz频段透射率大于40%,实现了带通滤波.当圆孔阵列超材料与热释电探测器保持足够间距时,在0.315 THz点频其噪声等效功率为11.29μW/Hz^0.5,是带通波段外0.1 THz噪声等效功率的6.3%,实现了带通探测;当圆环孔阵列超材料与热释电探测器贴合时,在0.315 THz点频其噪声等效功率为4.64μW/Hz^0.5,是无圆环孔阵列超材料探测器噪声等效功率的29.4%,实现了窄带探测.上述结论可用于生物成像、大分子探测等领域中特定太赫兹波段的带通与窄带探测.     

基于液晶调制器调制的实时测温系统

分析了一种基于基尔霍夫定律的钽酸锂(LiTaO3)热释电探测器作为接收元件的实时测温系统中,机械式调制盘对测量精度影响,提出了改变机械式调制盘对测量精度的影响的方法;介绍了液晶调制器的结构、对辐射调制的原理以及在使用过程中的优点。设计了利用液晶调制器替代机械调制器的钽酸锂热释电实时测温系统。结果表明,利用液晶调制器改进后的测温系统在给定的温度范围中,测量精度均有明显的改善,符合测量要求。     

一种高精度光纤测温系统工作波长的优化设计

基于基尔霍夫定律 ,利用钽酸锂热释电探测器设计了一种实用化的双波长、高精度光纤测温系统。依照测温系统中单个探测器的温度分辨力、R(T)～T曲线的线性度、R(T)～T曲线的温度灵敏度及其相对温度灵敏度与各主要技术参量之间的关系 ,对采用钽酸锂热释电探测器作光电转换器件实现的实用化实时测温系统的工作波长进行了优化设计。实验表明 ,在测温范围 4 0 0～ 130 0℃内 ,当系统工作在λ1=2 .1μm、λ2 =2 .3μm时 ,其温度灵敏度高于 1.0× 10 -4℃ -1,相对温度灵敏度不低于 0 9,测温精度不低于 0 15 %。均符合设计要求     

利用红外光谱吸收原理的CO浓度测量装置研究

介绍了一种基于红外光谱吸收原理 ,利用钽酸锂热释电探测器实现一氧化碳浓度测量的装置。该装置主要由探测器系统、信号放大与处理系统及显示报警系统三部分组成。介绍了该装置的工作原理、基本结构及主要技术指标。讨论了其中的技术难点及其相应的解决方法。     

超薄LiTaO3晶片的键合减薄技术

在制造红外热释电探测器阵列过程中，需要利用超薄钽酸锂(LiTaO₃)晶片作为红外热释电探测器件的敏感层。通常LiTaO₃晶片的厚度远厚于红外热释电探测器件要求的厚度，所以需要采用键合减薄技术对LiTaO₃晶片进行加工处理。键合减薄技术主要包括：苯并环丁烯（BCB）键合、铣磨、抛光、加热剥离、刻蚀BCB。加工后得到面积为10mm×10mm、厚度为25μm的超薄单晶LiTaO₃薄膜，晶片厚度、表面粗糙度和面形精度比较理想。测得了LT晶片减薄后的热释电系数为1.6×10^-4Cm^-2K^-1。得到的单晶LiTaO₃薄膜满足红外热释电探测器敏感层的要求。     

KAT,KLT系列热释电探测器

利用热释电材料的热释电效应做成的光电接收器件称作热释电探测器.目前广泛用于制作热释电探测器的热释电单晶主要有两种:一种是硫酸三甘肽晶体(TGS)及其同类晶体(LATGS和 DLATGS等);另一种是袒酸锂晶体(LiTaO3).相应地,我们单位研制的热释电探测器有两个系列:KAT系列(由DLATGS     

热释电双波长光纤测温仪的精度分析

在介绍一种利用钽酸锂热释电探测器实现的实用化双波长光纤测温仪的基础上,着重讨论了反射辐射、探测器周围环境的热辐射、仪器工作波长的带宽,以及光路中选择性吸收气体的光谱吸收等多种因素对仪器测温精度的影响,并提出了相应的抑制措施。实验表明,采取相应的抗干扰措施后,在系统要求的测温范围400—1360℃内,其测温精度符合设计要求。     

热释电效应的几种应用

晶体的32种对称类型中有21种没有对称中心,而在具有压电性的20种无对称中心的点群中,有10种点群的晶体具有热释电效应.这类晶体存在固有的自发极化,当晶体的温度变化时,自发极化强度也随之改变,与极化强度方向垂直的晶体表面产生过剩的热释电电荷.最早观察到热释电现象的矿石是电气石.十九世纪初发现罗息盐(酒石酸钾钠)的热释电性,以后又陆续发现很多晶体具有热释电性能.目前常用的红外探测器材料有硫酸三甘肽(TGS)、钽酸锂、铌酸锶钡以及钛酸铅陶瓷等.实用的热释电材料都是铁电体,它们的极化强度能随外加电场而反转.二十世纪三十年代有人…     

一种实用化实时测温系统工作波长优化设计的进一步分析

基于Kirchhoff定律,依照测温系统的各主要技术参数与各主要技术指标(温度分辨力、测温灵敏度、相对测温灵敏度及测温准确度)之间的关系,对利用激光并采用钽酸锂热释电探测器作光电转换器件的实用化实时测温系统的工作波长进行了进一步的优化设计.实验表明,在测温范围400~1200 ℃内,系统的测温误差符合设计要求.     

用热释电探测器实现比色测温

用钽酸锂热释电探测器实现的火焰温度实时测量系统 ,主要由光学接收系统、信号放大与处理系统及显示系统三部分组成。其中 ,光学接收系统主要包括光学接收镜头、调制盘、截止滤光片、窄带干涉滤光片、聚焦透镜及光电转换系统等 ;信号放大与处理系统主要包括前置放大电路、选频放大电路、采样保持电路、模数转换电路及 80 3 1单片机等 ;显示系统主要包括数字显示器、打印机及接口电路等。介绍了该系统的工作原理与基本结构 ,讨论了其中的技术难点及相应的解决方法 ,分析了各量的测量精度对温度测量精度的影响。     

Planarization of CMOS ROIC dies for uncooled detectors

This paper presents a planarization procedure to achieve a flat CMOS surface of Readout Integrated Circuit (ROIC) for the integration between uncooled infrared detector arrays and ROIC. The CMOS fabrication process produces about 2 μm surface roughness on the silicon wafer, so the CMOS dies must be first planarized before integration with the detector arrays. To acquire a satisfying surface roughness in the small CMOS die, three commercially available polymers including bisbenzocyclobutene (BCB) and two types of polyimides are evaluated in our experiments. BCB shows the best results for our applications. A single layer of BCB coating successfully reduce the surface topology from 2 μm to less than 1500 Å and two layers of BCB coating reduce the surface topology to about 600 Å.     

混成式热释电非制冷红外焦平面探测器技术

介绍了混成式热释电焦平面探测器的基本结构和主要制备工艺流程以及国内外研究现状。混成式热释电焦平面探测器的关键制备技术主要包括热释电材料的优选与减薄技术,铟柱倒装焊混成技术、热隔离技术和读出集成电路技术等。指出了混成式热释电焦平面探测器的发展趋势。     

微型红外线传感技术的最新发展

综述了红外传感器技术的最新发展，由于应用了薄膜型红外探测器，衍射光学聚光镜和共振压电斩波器，红外传感器实现了微型化，在许多领域中获得了广泛的应用。     

New method for determining the thermal diffusion coefficient of thin films using ferroelectric crystals

A new method for determining the thermal diffusion coefficient of thin dielectric films deposited on a ferroelectric crystal detector is presented. The surface of the specimen was periodically heated by a rectangular modulated heat flow. The impact of the ratio of the film thickness to the detector thickness, as well as the film thermal diffusion coefficient on the shape of the system’s pyroelectric response is analyzed. Optimal conditions for the measurements are offered. Approbation of the method was carried out on an unannealed lead zirconate titanate (PZT) film deposited on a lithium tantalate crystal. The thermal diffusion coefficient of the specimen was α = 1.5 × 10⁻⁷ m²/s, which correlates with an independent estimation of this magnitude for polarized films.     

Role of cleaning methods on bond quality of Ti coated glass/imidex system

Thin film materials are widely used in the fabrication of semiconductor microelectronic devices. In thin film deposition, cleanliness of substrate surface have become critically important as over 50% of yield losses in integrated circuit fabrication are caused by microcontamination [1]. There are many wafer cleaning techniques. The most successful approach for silicon wafer cleaning technique is RCA clean [2]. But for glass substrate it is still not known which procedure of cleaning is the best. This paper provides an understanding of the right way of glass wafer cleaning method, with a focus towards identifying good bond strength. Two wafer cleaning techniques have been used for cleaning glass substrates in the context of laser micro-joining of dissimilar substrates. First cleaning procedure involves two steps, first cleaning in acetone solution and then in DI water solution. After each step dried with N₂. Second cleaning procedure involves four steps, first cleaning with 1% Alconox solution, second in DI water, third in acetone solution and finally in a methanol solution and dried with N₂ after each step. Deposition of Ti thin film on top of these two types of substrate using DC magnetron sputtering method also showed better adhesion of Ti film on glass for the second type of cleaning method. Scanning electron microscopy (SEM) analyses of the lap shear tested failed surfaces for these two kinds of samples revealed strong bond for samples prepared by second cleaning method compared to first cleaning method. Characterization of these two sets of samples using X-ray photoelectron spectroscopy (XPS) has shown excellent contamination removal for the second cleaning method. This modification is believed to be due to reduction of carbon contamination.     

一种微波光子探测器组件的封装设计与实现

为实现微波光子系统的高集成度、高可靠性，进行了一种微波光子探测器组件的封装设计与实现。介绍了定制化封装设计思路，选择可伐合金作为壳体材料，采用的卧式贴装方案中选用斜面透镜光纤，给出了封装工艺流程和关键工艺点，最终封装的组件光电耦合效率在68%～79%之间，满足总体指标需求。该组件通过混合集成封装方法，实现了微波芯片与光子芯片在同一封装内的阵列化集成及气密性封装。该组件的封装设计与实现方法，可用于其他微波光子产品，有助于提升光载射频传输系统的集成度与可靠性。     

热释电红外探测器在安全防护系统中的应用研究

利用人体发出的红外线,通过热释电红外传感器的接收和放大,形成具有一定电压幅度的控制信号,用这一控制信号去触发语音录放电路工作,就可制成具有自动控制功能的热释电红外探测语音录放系统。电路采用最新热释电红外探测模块与语音录放模块设计,当有人出现在热释电红外探测模块的探测范围时,热释电红外传感器首先将接收到的红外辐射能转换成电能信号,再经内部电路放大、比较处理后输出控制信号,触发语音录放模块工作,播放事先录制好的语音内容,提醒人们注意。该系统电路简洁、成本低、抗干扰能力强、耐低温、免调试、工作稳定和使用方便。适宜于安装在变电所、高压开关柜和电力变压器等危及人身安全的处所使用。     

On the heating modulation frequency dependence of the photopyroelectric signal in experiments for liquid thermal characterization

A pyroelectric sensor can be seen as a layered system consisted on a pyroelectric material sandwiched between two thin metal layers acting as electrical contacts for measurements of the voltage drop that can be induced by heating. This kind of sensor can be used as a detector of electromagnetic radiation but also for thermal characterization of materials using the photopyroelectric technique. In this work we perform a theoretical analysis based in the so-called thermal wave approach to show that, when this sensor is heated periodically by the absorption of intensity modulated light by one of the metalized surfaces, while the other metal surface is in contact with a liquid sample, the resulting pyroelectric voltage signal amplitude enhances respecting the one resulting from the bare sensor, for certain values of the modulation frequency. This contradicts the intuitively expectation based in the assumption that the sample provides a new channel for heat conduction, thereby decreasing the pyroelectric temperature. We will show that the back and forth propagation and the superposition of thermal waves through the metal coatings must be taken into account in order to explain the observed behavior. The proposed model was experimentally tested for water and glycerin samples, and using a polyvinylidene difluoride (PVDF) polymer film, with Ni–Cu metal electrodes, as a pyroelectric sensor.     

Large format two-color CMOS ROIC for SLS detectors

The ISC0905 is a 640 × 512, large format, two-color CMOS readout integrated circuit (ROIC) designed for strained-layer superlattice (SLS) detectors. The detector interface is supported through one input pad in each 30 μm pixel. One bit in the serial control word programs the chip to automatically adjust all biases and timing to allow for the integration of either electrons or holes. This feature allows users to easily operate this ROIC with a wide variety of p-on-n or n-on-p detectors. The ROIC has been specifically designed to allow for both polarities of detectors to be placed back-to-back and to connect to the ROIC through a single input pad to obtain a two-color image. The two-color image is achieved by switching the ROIC mode between the two colors on a per frame basis. This paper will describe the interface, design and features of the ISC0905 ROIC as well as a summary of the characterization test results.