高Tc超导探测器的进展与应用前景

描述了高Ｔｃ超导体检测红外辐射的机理和高Ｔｃ超导红外探测器的技术水平,介绍了亚微米结构器件、４×４元面阵以及ＨＢＣＣＯ超导体的研究结果,最后简要讨论了这一技术的应用前景     

微透镜列阵提高红外探测器探测能力的方法研究

研究用微光学方法提高红外探测器探测能力的机理,通过实验将锗微透镜列阵耦合到180元HgCdTe焦平面红外探测器上,使耦合组件探测率提高到原来的2．8倍,提出的光学耦合效应概念为客观评价微光学聚能元件综合质量及耦合机构性能提供了一种新的方法。还对微透镜列阵的冷屏效应进行了讨论。     

高Tc超导薄膜红外探测器领结型天线

为了提高超导薄膜红外探测器的工作带宽、响应速度和灵敏度,并便于进行集成平面工艺,我们设计了微桥型红外敏感元及与其耦合的领结型平面天线(bow-tie antenna),其检测波长范围可从中红外到毫米波段,理论估算其NEP(噪音等效功率)值可达1.2×10^-12WHz^1/2,响应时间τ<10^-6s.     

高Tc超导薄膜及电子器件

在 198 7年初,发现液氮温区超导体几星期之内,研究高温超导薄膜及其器件的工作在各国也随之广泛地展开.由于它在电子学方面的实际应用前景诱人,这些研究工作以前所未有的步伐发展着.这些应用包括单层型器件(如简单互连线、红外探测器和许多微波无源器件)和多层型器件[如复杂的互连线、超导量子干涉器件(SQUID)和约瑟夫森(Josephson)集成电路].在实验室范围内人们已经实现了上述单层型器件的应用,多层型器件也正在发展之中. 超导薄膜的制备是第一个目标.钇钡铜氧(YBa2Cu3O7-x)是首先发现的也是研究得最多的材料.各种物理气相淀积、化学气…     

用于雪崩光电探测器响应度增强的超透镜设计与仿真

超透镜除了可以实现传统透镜的聚焦和成像功能之外,还可通过对超构单元的设计实现对光场偏振、波长和振幅等的多维度操控,由于体积薄、重量轻、成本低、易集成,其在光电子器件领域中开始崭露头角,已经成为当前的研究热点和重要方向。本文采用时域有限差分算法(Finite-difference time-domain,FDTD)设计并优化了基于InGaAs雪崩探测器原位集成的超透镜,同时估算了超透镜的聚焦效率和透射率。仿真结果表明,超透镜将入射光会聚至探测器的光敏区中,透射率达到82.8%,并且在目标焦距150μm、超透镜半径50μm时聚焦效率达到84.89%。为进一步提高透射率,在超透镜表面增加抗反射层(AR Layer)。结果表明,300nm的SiO₂层透射率达到最大值86.6%,250 nm的SiN层透射率达到最大值87.6%,透射率比未增加AR层时分别增加了3.8%和4.8%。最后计算得出集成超透镜的探测器吸收区光场能量比未集成超透镜的探测器吸收区光场能量提升了250.96倍,将极大提升探测器的响应度。本文提出了单片集成超透镜的雪崩探测器设计方案,将雪崩探测器光敏区之外的...     

一种浸没透镜结构HgCdTe红外探测器组件环境适应性研究

探测器采用浸没透镜结构的单元光伏芯片,工作波段为2.5~3.2μm。采用储能焊TO9管壳封装,将二级热电致冷器、热敏电阻、透镜结构的HgCdTe红外探测器封装为一红外探测器组件,组件可在室温至-50℃下工作,经过老炼、力学和热学环境适应性试验后,结果表明,HgCdTe红外探测器的零偏电阻(R_0)变化率、探测器峰值电流响应率(R_(λ_p,I))变化率和热电致冷器(TEC)的交流阻抗(R)的变化率均小于5%,探测器暗电流I_d@-0.1V≤9×10^(-7)A,探测器的漏率优于1×10^(-7)Torr·l/s,组件的密封性达到了航天要求。     

用于红外探测器的高红外吸收率结构研究进展

高红外吸收是实现高灵敏度红外探测器的一个重要途径。探测器的响应率与热吸收率紧密相关。高红外吸收将提升红外探测器的探测性能。鉴于高吸收率的重要性,对国内外研究中典型的高红外吸收结构的研究进展进行介绍。目前典型新型高吸收结构有基于新型材料(如超材料)的高吸收结构和基于金属光栅高吸收结构。研究表明这些结构在某些波段可实现近100%的完美吸收,是发展高灵敏探测器的新途径。     

中红外宽带消色差超透镜的设计

中红外热成像系统是通过探测物体本身的辐射进行成像,不需要外部光源。而传统的中红外热成像系统体积大,不利于小型化。本文基于传输相位理论,采用时域有限差分（FDTD）法,使用FDTD软件计算仿真,探究了不同的单元半径、纳米柱高度及单元周期对相位延迟及透过率的影响,并且针对不同的纳米柱半径,利用传输相位调控实现中红外（3～5μm）波长下全介质硅材料的宽带消色差超透镜设计。其数值孔径为0.24,仿真焦距值为147.3μm,半峰全宽（FWHM）为8.11μm,透镜透过率达到70%。设计的超透镜不仅体积小、质量轻、全波长聚焦效率可达到54%,而且为平面透镜,因此易于光学系统集成,在红外成像、红外夜视仪、红外遥感等技术中展现出广阔的应用前景。     

激光蒸发淀积高Tc超导薄膜

本文简要介绍激光蒸发淀积高Ｔｃ超导薄膜技术的基本原理．主要工艺特点，各种激光器在制备高Ｔｃ超导薄膜中的应用及所取得的重要成果．     

Spin split-off transition based IR detectors operating at high temperatures

GaAs/AlGaAs based Heterojunction Interfacial Workfunction Internal Photoemission (HEIWIP) detectors were used to demonstrate experimental split-off response that is based on hole transitions between light/heavy hole bands and the split-off band (spin-orbit). Preliminary results indicate that, this detection mechanism is more efficient than free carrier mechanism for NIR operation. An unoptimized, GaAs/AlGaAs detector with a free carrier threshold wavelength of 20 μm showed a maximum operating temperature of 130 K for split-off response in the range 1.5–5 μm with a peak D^* of 1.0 × 10⁸ Jones. By adjusting the free carrier threshold to match the split-off threshold, it should be feasible to further increase the operating temperature. Analysis indicates that practical devices with properly optimized parameters are capable of achieving room temperature operation with higher specific detectivity. The possible ways to tailor the threshold, for the split-off response to different wavelength rangers using different materials such as phosphides and nitrites are also discussed.     

溶胶-凝胶法制备高折射率TiO2薄膜

采用溶胶- 凝胶法制备了TiO2纳米晶溶胶,并以旋涂法（spin-coating）镀制了高折射率光学薄膜。借助光散射技术和透射电镜研究了溶胶的微结构。采用原子力显微镜、场发射扫描电镜、紫外-可见-近红外光谱仪、椭偏仪、漫反射吸收光谱及强激光辐照实验,对膜层的结构、光学性能及抗激光损伤性能进行了系统的表征。结果显示:纳米晶薄膜的折射率达到了1.9,而传统的溶胶-凝胶薄膜折射率只有1.6;同时纳米晶薄膜的抗激光损伤阈值与传统的溶胶-凝胶薄膜相差不大,在1 064 nm处分别为16.3 J/cm2(3 ns脉冲) 和16.6 J/cm2(3 ns脉冲);纳米晶溶胶薄膜可以在保持较高抗激光损伤阈值情况下,大幅度提高薄膜折射率。     

High-performance IR detectors at SCD present and future

For over 27 years, SCD has been manufacturing and developing a wide range of high performance infrared detectors, designed to operate in either the mid-wave (MWIR) or the long-wave (LWIR) atmospheric windows. These detectors have been integrated successfully into many different types of system including missile seekers, time delay integration scanning systems, hand-held cameras, missile warning systems and many others. SCD’s technology for the MWIR wavelength range is based on its well established 2D arrays of InSb photodiodes. The arrays are flip-chip bonded to SCD’s analogue or digital signal processors, all of which have been designed in-house. The 2D focal plane array (FPA) detectors have a format of 320×256 elements for a 30-μm pitch and 480×384 or 640×512 elements for a 20-μm pitch. Typical operating temperatures are around 77–85 K. Five years ago SCD began to develop a new generation of MWIR detectors based on the epitaxial growth of antimonide based compound semiconductors (ABCS). This ABCS technology allows band-gap engineering of the detection material which enables higher operating temperatures and multi-spectral detection. This year SCD presented its first prototype FPA from this program, an InAlSb based detector operating at a temperature of 100 K. By the end of this year SCD will introduce the first prototype MWIR detector with a 640×512 element format and a pitch of 15 μm. For the LWIR wavelength range SCD manufactures both linear Hg_1−xCd_xTe (MCT) detectors with a line of 250 elements and time delay and integration (TDI) detectors with formats of 288×4 and 480×6. Recently, SCD has demonstrated its first prototype uncooled detector which is based on VO_x technology and which has a format of 384×288 elements, a pitch of 25 μm, and a typical NETD of 50 mK at F/1. In this paper, we describe the present technologies and products of SCD and the future evolution of our detectors for the MWIR and LWIR detection. The paper presented there appears in Infrared Photoelectronics, edited by Antoni Rogalski, Eustace L. Dereniak, Fiodor F. Sizov, Proc. SPIE Vol. 5957, 59570S (2005).     

Determination of thin film refractive index and thickness by means of film phase thickness

A new approach for determination of refractive index dispersion n(λ) (the real part of the complex refractive index) and thickness d of thin films of negligible absorption and weak dispersion is proposed. The calculation procedure is based on determination of the phase thickness of the film in the spectral region of measured transmittance data. All points of measured spectra are included in the calculations. Barium titanate thin films are investigated in the spectral region 0.38–0.78 μm and their n(λ) and d are calculated. The approach is validated using Swanepoel’s method and it is found to be applicable for relatively thin films when measured transmittance spectra have one minimum and one maximum only.      

轻量化超宽温度折/衍混合红外热像仪光学系统设计

设计一个用于红外热像仪的轻量化超宽温中波折/衍混合红外热像仪光学系统。光学系统参数:工作波段为3.7 m～4.8 m,相对孔径为1/2,焦距为120 mm,全视场角为5.18,满足100 %冷光栏效率。采用三片式结构,使用硅和锗两种常用的红外材料,以及一个非球面和一个衍射面,系统实现了轻量化和超宽温度下工作。系统在-60℃～160℃温度范围内成像质量接近衍射极限,可供像元尺寸为30 m、像元数256256的凝视型中波红外探测器使用,可探测到2.3 km远的坦克目标。     

周期结构薄膜在折射率色散下反射区特性研究

周期性结构是光学薄膜设计的基本物理模型,给出了反射区中心波长的一般性条件,研究了在膜层材料存在折射率色散情况下,等厚周期结构和非等厚周期结构的薄膜反射区中心波长与带宽特性.研究结果表明:在等厚和非等厚周期结构中,考虑膜层材料折射率色散与忽略色散情况相比,中心波长向长波方向移动,反射级次与相对波数的线性关系偏离;在薄膜光学厚度一定的非等厚周期结构中,高折射率层光学厚度大于低折射率层时,反射级次与相对波数的线性关系偏离度高;非等厚周期结构薄膜的带宽在低反射级次上小于等厚周期结构,同时膜层的色散对反射带宽影响不大.     

高温超导体和巨磁阻薄膜激光感生热电电压的最佳膜厚研究

根据高温超导体(HTSC)和巨磁阻（CMR）薄膜中激光感生电压信号的时间关系公式，进一步导出产生最大激光感生电压所需的薄膜最佳厚度的方程式.结果表明，感生电压不是简单地与厚度的倒数成正比，而是存在一个最佳厚度 .该方程给出了影响器件响应设计的主要因素，讨论了决定最佳厚度的薄膜参数，并与实验结果进行比较. 关键词： 激光感生电压 最佳厚度 HTSC CMR 探测器     

三光窗杜瓦红外探测器抗干扰设计

文中就斯特林制冷机应用在三光窗杜瓦红外探测器组件中对红外探测器的信号产生的干扰问题进行了多方面探讨、测试及分析研究。从制冷机驱动电源入手 ,研制出了一种低干扰制冷机驱动电源 ,并对整个系统的安装调试进行了抗干扰设计 ,有效地控制了系统对探测器芯片信号产生的干扰 ,使其达到用户要求     

紫外衍射微透镜阵列的设计与制备

为了提高紫外焦平面阵列的填充因子,可以通过微透镜阵列与紫外焦平面阵列的集成,以改善紫外焦平面阵列的探测性能。根据标量衍射理论设计了用于日盲型紫外焦平面阵列的128×128衍射微透镜阵列,其工作中心波长为350nm,单元透镜F数为F/3.56。采用组合多层镀膜与剥离的工艺方法制备了128×128衍射微透镜阵列,对具体的工艺流程和制备误差进行了分析,测量了衍射微透镜阵列的光学性能。实验结果表明:衍射微透镜阵列的衍射效率为88%,与理论值95%有偏差,制备误差主要来自对准误差和线宽误差。紫外衍射微透镜阵列具有均匀的焦斑分布,与紫外焦平面阵列单片集成能较好地改善器件的整体性能。     

Design and fabrication of a negative microlens array

An operation model of a negative microlens array is demonstrated. The array consists of two kinds of materials with different refractive indices. First of all, a positive microlens array with 256×256 elements serving as a pattern is fabricated by argon ion beam etching on the quartz. The diameter and average corona height of the element are 28 and 0.638 μm, respectively. The spacing between two neighboring elements is 2 μm. In the second phase, after being coated by epoxy, the positive microlens array pattern is spun and baked, leading to a complex negative microlens array. Surface stylus measurement shows that the surface of the positive quartz microlens array is smooth and uniform. Focal length measurement of the negative microlens array indicates that the focal length region with −731±3 μm is in good agreement with the theoretical calculation value of −729 μm.