a r X i v :0806.1379v 1 [h e p -e x ] 9 J u n 2008
High-p T photon processes and the photon structure -results from HERA jet and prompt photon (photo)production
T.Sch¨o rner-Sadenius a ?
a
Hamburg University,Institute for Experimental Physics,Luruper Chaussee 149,22761Hamburg,Germany
Many important QCD tests with jets and prompt photons have been performed with the experiments H1and ZEUS at the HERA ep collider.This contribution focuses on results from jet and prompt photon photoproduction.In particular,the concept of resolved photon interactions and various jet cross sections and their sensitivity to the photon (and proton)PDFs will be discussed.In addition,recent results from prompt photon production will be shown.Finally results on multi-parton interactions and the underlying event will be presented.
1.INTRODUCTION
HERA,the world’s only ep collider,stopped operation in June 2007after 15years of success-ful operation.Until that day,the experiments H1and ZEUS had each accumulated about 0.5fb ?1of integrated luminosity.A major upgrade of ma-chine and detectors in the years 2001to 2003(be-tween the so-called HERA-I and HERA-II data taking periods)proved very fruitful and led to an increase in luminosity of almost a factor 5.In the ?nal years of data taking,the proton and elec-tron/positron beam energies were 920GeV and 27.5GeV,respectively.
In photoproduction at HERA,a quasi-real pho-ton emitted from the incoming electron collides with a parton from the incoming proton.In such events,hadronic jets and also prompt (meaning:radiated by one of the outgoing quarks)pho-tons can be produced.The photoproduction of hadronic jets can be classi?ed into two types of processes in leading-order (LO)QCD:In direct processes,the entire photon and its momentum participate in the hard scatter (left side of Fig.1).Resolved processes involve a photon acting as a source of quarks and gluons,with only a photon momentum fraction x γparticipating in the hard scatter (right side of Fig.1).It is due to resolved
2T.Sch¨o
rner-Sadenius
Figure1.Feynman diagrams of direct and re-solved dijet photoproduction at LO.
2.THE CONCEPT OF THE RESOL VED
PHOTON
Fig.
1shows Feynman diagrams for direct (left)and resolved(right)photoproduction of di-jets.Statistically,direct events are dominated
by quark propagators whereas resolved events are mostly characterized by gluon propagators.This di?erence should lead to a distinctly di?erent an-gular behaviour of the?nal-state jets:Whereas the quark propagator(quarks being spin-1/2par-ticles)should lead to a distribution in the co-sine of the CMS scattering angle,cosθ?,like (1?|cosθ?|)?1,in the gluon case a distribution like(1?|cosθ?|)?2is expected.In other words, the cross section of the resolved part is expected to rise more rapidly towards higher cosθ?than that of the direct part.Fig.2shows the experi-mental evidence[1]:Shown is the cross section as function of cosθ?for a direct-enriched(left)and a resolved-enriched data sample(right).It is obvi-ous that the above predictions are ful?lled,the re-solved distribution rising much more rapidly than the direct one.These distributions thus form an important test of the concept of the resolved pho-ton(similar results have been obtained by the ZEUS collaboration[2]).
In the above discussion,the distinction between direct and resolved data samples has been made. On the theoretical side,this distinction is mean-Figure2.Photoproduction dijet cross section as function of CMS scattering angle,cosθ?,for a direct-and a resolved-enriched sample[1]. ingful only at LO.On the experimental side,the distinguishing observable xγis not directly acces-sible but has to be reconstructed from the two ?nal-state jets in much the same way as the pro-ton’s momentum fraction x p entering the hard scattering,
xγ=
E T,1e?η1+E T,2e?η2
2E p
,
with the jet transverse energies and pseudorapidi-ties E T,i andηi,the inelasticity y(characterizing the energy loss of the scattered electron)and the electron and proton beam energies E e and E p. Typically,the resolved regime is de?ned to com-prise values of xγbetween0and0.75or0.8.
3
10
10d σ / d Q 2 (p b /G e V 2)
(D A T A -N L O ) / N L O
of Q ton tion a of The the It is tion by by Figure 4.Photoproduction dijet cross sections as functions of the mean transverse jet energy,
E T ,separately for a sample enhanced in
direct and a sample enhanced in resolved events.The data are compared to an NLO QCD predic-tion using two di?erent parametrizations of the photon PDFs.
Especially the data in the direct regime are very well described by the theory (on the level of 10%or better),as can be seen in the bottom left part of the ?gure which shows the ratio of data over NLO prediction.The uncertainties here are dominated by the theory uncertainty which is of the order of 15%.The situation in the resolved regime is slightly more complicated and will be
4
T.Sch¨o rner-Sadenius
Figure 5.Photoproduction dijet cross sections as functions of the momentum fraction x p for a direct-and a resolved enriched sample [1].
discussed in some more detail below.
Many more examples of photoproduction jet cross sections and their successful description by NLO QCD exist.Fig.5[1]shows the dijet cross section as a function of x p in di?erent regions of x γand of the jet pseudorapidities.Both the mo-mentum fractions and the pseudorapidity distri-butions of the jets are sensitive to the momentum distributions of partons inside the proton,making these measurements important tests of QCD.It can be seen that,again,the data are very well de-scribed by NLO QCD,on the level of 10%,which are well covered by the combined uncertainties.Only for large x p values with both jets going for-ward (η1,2>1)some deviations between data and theory occur (Fig.5,bottom right)which might be explained by the large uncertainties on the proton PDFs for large momentum fractions.Fig.6[4]shows,for the same data sample as in
Figure 6.Photoproduction dijet cross sections as
functions of the mean jet pseudorapidity,
η.The data are again shown
separately for a direct and a resolved sample and are compared to NLO QCD predictions using dif-ferent parametrizations of the photon PDFs.For the direct case,the description of the data by the theory is again excellent.
The demonstrated good performance of NLO QCD in describing photoproduction data (espe-cially in the direct regime)gives con?dence in the theory,thus rendering possible the extrac-tion of QCD parameters like the strong coupling constant αS or the proton and photon PDFs from the data.One example for the former is given in [5]where a value αS =0.1224±
0.0001(stat.)+0.0022?0.0019(exp.)±+0.0054
?0.0042(th.)was ex-tracted from an inclusive-jet measurement in pho-toproduction.The impact of jet cross sections on the PDFs is discussed in the next section.
High-p T photon results from HERA
5
Figure 7.Left:Theoretical uncertainties on pho-toproduction
dijet cross sections in a special kine-matic region [4].Right:Gluon-induced contribu-tions to photoproduction dijet cross sections in the same kinematic region.
4.JETS IN PHOTOPRODUCTION AND THE PDFs In [4]both the theoretical uncertainties on di-jet cross sections and their sensitivity to the gluon density in the photon and the proton have been investigated in great detail.As is highlighted in Fig.7(left)for a special choice of kinematics,there are regions in which the proton PDF uncer-tainty (indicated as the region between the two solid lines)is as large as or even larger than the combined uncertainty from the variation of the renormalization scale and the PDF uncertainties (indicated as the coloured area).Also the uncer-tainty due to the very imprecise knowledge of the photon PDF may be very large,reaching values of up to 60%,as is indicated by the dashed line in the ?gure which shows the di?erence in the cross section prediction between two di?erent photon PDF parametrizations.Dijet data therefore do have the potential to further constrain both quark and gluon densities in the photon and the pro-ton,as is indicated in Fig.7(right).The ?gure shows the fraction of gluon-induced events on the proton side (dark dashed line)and on the pho-
C r o s s s e c t i o n /t h e o r y
E T jet1
(GeV)
Figure 8.Ratio of data over NLO QCD predic-tions for photoproduction dijet events in the di-rect regime as function of jet transverse energy and pseudorapidity,E T and η[2].
ton side according to two di?erent photon PDF parametrizations (light dashed and solid lines).The amount of gluon-induced events can be as large as 60%,depending on the detailed kine-matics under consideration.
The large discrepancies between di?erent pho-ton PDF parametrizations is also visible in the comparison of NLO QCD predictions with dijet cross sections in the resolved regime like in Fig.4(right)or Fig.6(right).For example,in Fig.4,the resolved dijet cross section can be approx-imately described by the NLO prediction using the CJK photon PDF parametrization,but not by the AFG04parametrization which is o?by up to 40-50%.This di?erence highlights the poten-tial of the data to further constrain the photon PDFs.
6T.Sch¨o rner-Sadenius
Figure9.Improvement of gluon density by using jet data in NLO QCD?ts of the PDFs[6].
A?rst example of the bene?t of jet photo-production data on determinations of the proton PDFs is given in Figs.8and9.Fig.8shows, for an older measurement of photoproduction di-jet cross sections,the ratio of the measured cross sections over the NLO prediction.An overall good description is found,with data and theory in agreement almost everywhere within the com-bined theoretical and experimental uncertainties. These data(together with data from DIS jet anal-yses)have been used as additional inputs(be-sides the usual inclusive F2data)to an NLO QCD PDF?t.The success of this?t is demon-strated in Fig.9which shows the fractional gluon density uncertainty as a function of the proton momentum fraction x in di?erent regions of Q2. The uncertainty without the use of jet data is given by the dark shaded area,and the result including jet data is given by the light shaded area.An improvement in the uncertainty of up to35%is clearly visible especially in the region of medium/high x values.
The aim is to further improve the proton PDFs (and here especially the gluon density at high values of x as this is especially important for LHC physics)by using more precise or di?er-ent cross sections from both photoproduction and DIS.Constraining the photon PDFs will be tech-nically even more demanding,partly because of lack of a consistent PDF error treatment for the photon PDF,partly because of the increased ex-perimental and theoretical uncertainties for the resolved regime.
5.PROMPT PHOTON PRODUCTION The production of prompt photons from the hadronic?nal state o?ers an alternative access to the QCD dynamics in ep scatterings,with di?er-ent systematic uncertainties and reduced e?ects from hadronisation.Prompt photon production has been measured by ZEUS and H1in both DIS and photoproduction;in addition to inclu-sive measurements of prompt photons,often also photon+jet cross sections are measured for which there are also NLO QCD predictions available. Fig.10[7]shows the inclusive photon cross section(left)and the photon+jet cross section (right)in DIS as a function of the photon trans-verse energy,EγT.It can be seen that all LO pre-dictions are not able to describe the data.In contrast to that,the NLO theory curve in the photon+jet sample is compatible with the data. Similar results are obtained for the photopro-duction case[8],[9].Again,NLO calculations are needed to describe the data,and the additional requirement of a jet in addition to a prompt pho-ton brings data and theory closer together.
In summary,prompt photons might serve as a valuable place for QCD tests.Currently,however, the predictions are not yet in a state as to allow (for example)the use of prompt photon data in NLO QCD?ts of the PDFs or forαS extractions.
High-p T photon results from HERA7
Figure
10.Prompt photon production in DIS
events[7].Shown are the cross sections as func-
tions of photon transverse energy,Eγ
T ,for an in-
clusive photon and a photon+jets sample.
6.THE UNDERLYING EVENT AND
MULTI-PARTON INTERACTIONS As has been pointed out in the introduction, resolved photon-proton interactions may,in some respects,be regarded as hadron-hadron collisions, with all the additional features with respect to di-rect interactions.In particular,in hadron-hadron collisions it is possible to have multiple interac-tions of pairs of partons(‘multi-parton interac-tions’,MPI)which may populate the hadronic ?nal state with additional soft or hard jets or additional energy?ow throughout the detector. This e?ect may alter the?nal state signi?cantly, making it necessary to model it adequately in the Monte Carlo programs used in the analy-ses.There exist various MPI model implemen-tations in the standard generators HERWIG and PYTHIA which can be tested against data or whose parameters can be adjusted to describe the Figure11.Mean number of minijets as function of the leading jet p T[10].
data.Here,two recent examples of MPI studies at HERA will be brie?y discussed.
Fig.11[10]shows the the mean number of ‘minijets’(i.e.soft jets with transverse energies above a very low cut of3GeV)in events with at least one hard jet.The data are shown as a function of this leading jet’s transverse mo-mentum,p?T,lj,in di?erent regions of Q2and di?erent azimuthal-angle regions with respect to the leading jet’s azimuth.The‘Towards’and ’Away’regions are supposed to be mostly pop-ulated by the results of the?rst and hardest parton-parton scattering in the event,the dijet system coming from this scattering supposed to be separated by aboutπin azimuth.The‘High’and especially the‘Low’regions,in contrast,are supposedly particularly sensitive to MPI e?ects which in these regions are not masked out by the harder energy depositions from the leading
8T.Sch¨o rner-Sadenius jet pair(‘High’and‘Low’refer to the amount
of deposited energy in the two regions).It can
be observed that the PYTHIA model with MPI
e?ects switched on(‘PYTHIA MI’)is in rather
good agreement with the data in almost all re-
gions.In contrast PYTHIA without MPI model-
ing(‘PYTHIA’)fails to describe the data in the
low Q2‘High’and‘Low’regions,consistent with
the hypothesis of dominating MPI e?ects in these
regions of phase space.The data thus clearly in-
dicate the necessity of MPI e?ects in the models.
A similar statement is derived from a recent
measurement of three-and fourjet photoproduc-
tion[11].Fig.12shows the fourjet photoproduc-
tion cross section as a function of xγand com-
pares it to PYTHIA and HERWIG predictions
with and without the inclusion of MPI model-ing.It becomes clear that only the two pre-dictions including MPI e?ects(‘HERWIG+MPI’and‘PYTHIA+MPI’)can reproduce the data, whereas the models without MPI grossly under-estimate the data in the resolved regime(for xγ<0.8).The e?ect is particularly drastic for low energy scales and low invariant multijet masses,as in Fig.12where the fourjet mass was between25and50GeV.Again,the need for MPI contributions in the models is evident. However,the HERA data so far do not have the power to specify more precisely the mecha-nism underlying MPI e?ects or to shed light on the energy evolution of MPI e?ects when going (for example)from TEVATRON to LHC centre-of-mass energies.The models in use so far are rather crude and will have to be replaced by more realistic models and calculations which take cor-rectly into account features like multi-parton ex-changes between photon and proton,correlations between these exchanges,etc.
7.CONCLUSIONS
Several aspects of jet and prompt photon pro-duction(mainly)in photoproduction at HERA have been discussed.The power of NLO QCD in describing jet cross sections(and also prompt photon data)has been shown,and the potential of the data for further constraining the proton (and photon)PDFs has been pointed out.In ad-Figure12.Photoproduction fourjet cross section as function of xγ[11].
dition,some e?ects of MPI on HERA data have been discussed.
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采光窗种类、特性及使用范围 二、采光窗种类、特性及使用范围 (一)侧窗：侧窗构造简单，布置方便，造价低，光线的方向性好，有利于形成阴影，适于观看立体感强的物体，并可通过窗看到室外景观，扩大视野，在大量的民用建筑和工业建筑中得到广泛的应用。侧窗的主要缺点是照度分布不均匀，近窗处照度高，往里走，水平照度下降速度很快，到内墙处，照度很低，离内墙lm处照度最低。侧窗采光房间进深不要超过窗口上沿高度的2倍，否则需要人工照明补充。 侧窗分单侧窗、双侧窗和高侧窗三种，高侧窗主要用于仓库和博览建筑。 (二)天窗：随着建筑物室内面积的增大，只用侧窗不能达到采光要求，需要设计天窗。天窗分为以下几种类型： 1.矩形天窗：这种天窗的突出特点是采光比侧窗均匀，即工作面照度比较均匀，天窗位置较高，不易形成眩光，在大量的工业建筑，如需要通风的热加工车间和机加工车间应用普遍。为了避免直射阳光射入室内，天窗的玻璃最好朝向南北，这样阳光射人的时间少，也易于遮挡。天窗宽度一般为跨度的一半左右，天窗下沿至工作面的高度为跨度的0.35-0.7倍。 2.横向天窗(横向矩形天窗)：这种天窗比避风天窗采光系数高，均匀性好，省去天窗架，造价低，能降低建筑高度。设计时，车间长轴应为南北向，即天窗玻璃朝向南北。 3.锯齿形天窗：这种天窗有倾斜的顶棚作反射面，增加了反射光分量，采光效率比矩形天窗高，窗口一般朝北，以防止直射阳光进入室内，而不影响室内温度和湿度的调节，光线均匀，方向性强，在纺织厂大量使用这种天窗，轻工业厂房、超级市场、体育馆也常采用这种天窗。 4.平天窗：这种天窗的特点是采光效率高，是矩形天窗的2-3倍。从照度和亮度之间的关系式召E=L.Ω.cosa看出，对计算点处于相同位置的矩形天窗和平天窗，如果面积相等，平天窗对计算点形成的立体角大，所以其照度值就高。另外乎天窗采光均匀性好，布置灵活，不需要天窗架，能降低建筑高度，在大面积车间和中庭常使用平天窗。设计时应注意采取防止污染、防直射阳光影响和防止结露措施。 5.井式天窗：采光系数较小，这种窗主要用于通风兼采光，适用于热处理车间。 设计时，可用以上某一种采光窗，也可同时使用几种窗，即混合采光方式。 天然采光基本知识 二、采光窗种类、特性及使用范围 (一)侧窗：侧窗构造简单，布置方便，造价低，光线的方向性好，有利于形成阴影，适于观看立体感强的物体，并可通过窗看到室外景观，扩大视野，在大量的民用建筑和工业建筑中得到广泛的应用。侧窗的主要缺点是照度分布不均匀，近窗处照度高，往里走，水平照度下降速度很快，到内墙处，照度很低，离内墙lm处照度最低。侧窗采光房间进深不要超过窗
非制冷红外技术及应用 蓝海光学招募：镜头装配主管，镜头销售人员光学人生，你的精彩人生！一、红外热成像技术简介自然界所有温度在绝对零度（-273℃）以上的物体都会发出红外辐射，红外图像传感器则将探测到的红外辐射转变为人眼可见的图像信息。红外成像技术涵盖了红外光学、材料科学、电子学、机械工程技术、集成电路技术、图像处理算法等诸多技术，红外成像装置的核心为红外焦平面探测器。 二、非制冷红外技术概述2.1 非制冷红外技术原理非制冷红外探测器利用红外辐射的热效应，由红外吸收材料将红外辐射能转换成热能，引起敏感元件温度上升。敏感元件的某个物理参数随之发生变化，再通过所设计的某种转换机制转换为电信号或可见光信号，以实现对物体的探测。 非制冷红外焦平面探测器分类2.2 非制冷红外探测器的关 键技术 热释电型红外辐射使材料温度改变，引起材料的自发极化强度变化，在垂直于自发极化方向的两个晶面出现感应电荷。通过测量感应电荷量或电压的大小来探测辐射的强弱。热释电红外探测器与其他探测器不同，它只有在温度升降的过程中才有信号输出，所以利用热释电探测器时红外辐射必须经过调制。探测材料：硫酸三甘肽、钽酸锂、钽铌酸钾、钛（铁
电）酸铅、钛酸锶铅、钽钪酸铅、钛酸钡热电堆由逸出功不同的两种导体材料所组成的闭合回路，当两接触点处的温度不同时，由于温度梯度使得材料内部的载流子向温度低的一端移动，在温度低的一端形成电荷积累，回路中就会产生热电势。（塞贝克效应Seebeck）而这种结构称之为热电偶。一系列的热电偶串联称为热电堆。因而，可以通过测量热电堆两端的电压变化，探测红外辐射的强弱。二极管型利用半导体PN结具有良好的温度特性。与其他类型的非制冷红外探测器不同，这种红外探测器的温度探测单元为单晶或多晶PN结，与CMOS工艺完全兼容，易于单片集成，非常适合大批量生产。热敏电阻型（微测辐射热计）利用热敏电阻的阻值随温度变化来探测辐射的强弱。一般探测器采用悬臂梁结构，光敏元吸收红外热辐射，由读出电路测量热敏材料电阻变化而引起的电流变化，通过读出电路对电信号采集分析并读出。探测器一般采用真空封装以保证绝热性好。探测材料：氧化钒、非晶硅、钛、钇钡铜氧等氧化钒VOx的TCR 一般为2%~3%，特殊方法制备的单晶态VO2和V2O5可达4%。VOx具有电阻温度系数大，噪声小的特点，被广泛用作非制冷式红外焦平面传感器的热敏材料。全球的非制冷红外热像仪市场中，使用VOx非制冷红外探测器的占80%以上。氧化钒VOx的制备方法：溅射法、溶胶-凝胶法、脉冲激光沉积法、蒸发法。读出电路IC技术ROIC对微弱的红
中远红外探测器发展动态 1 红外光电探测器的的历史 红外探测成像具有作用距离远、抗干扰性好、穿透烟尘雾霾能力强、可全天候、全天时工作等优点在军用和民用领域都得到了极为广泛的应用按照探测过程的物理机理，红外探测器可分为两类即热探测器和光电探测器。光电探测器的工作原理是目标红外辐射的光子流与探测器材料相互作用，并在灵敏区域产生内光电效应。因具有灵敏度高、响应速度快的优点，光电探测器在预警、精确制导、火控和侦察等红外探测系统中得到广泛应用。 红外焦平面阵列可探测目标的红外辐射，通过光电转换、电信号处理等手段，可将目标物体的温度分布图像转换成视频图像，是集光、机、电等尖端技术于一体的红外光电探测器H。目前许多国家，尤其是美国等西方军事发达国家，都花费大量的人力、物力和财力进行此方面的研究与开发，并获得了成功。红外光电探测器研究从第一代开始至今已有40余年历史，按照其特点可分为三代。第一代(1970s～1980s)主要是以单元、多元器件进行光机串／并扫描成像，以及以4×288为代表的时间延迟积分(TDI，time delay integration)类扫描型(scanning)红外焦平面列阵。单元、多元探测器扫描成像需要复杂笨重的二维、一维扫描系统结构，且灵敏度低。第二代红外光电探测器是小、中规格的凝视型(staring)红外焦平面列阵。M×N凝视型红外焦平面探测元数从1元、N元变成M×N元，灵敏度也分别从l与N1/2增长M×N1/2倍和M1/2。而且，大规模凝视焦平面阵列，不再需要光机扫描，大大简化整机系统。 目前，正在发展第三代红外光电探测器。探测器具有大面阵、小型化、低成本、双色(two-color)与多色(multi-color)、智能型系统级灵巧芯片等特点，并集成有高性能数字信号处理功能，可实现单片多波段融合高分辨率探测与识别。因此，本文将重点综述三代红外光电探测器的材料体系及其研究现状，并分析未来红外光电探测器的材料选择及发展趋势。 2 三代探测器的材料体系与发展现状 红外光电探测器的材料很多，但真正适于发展三代红外光电探测器，即响应波段灵活可调的双色与多色红外焦平面列阵器件的材料则很少。目前，主要有传统的HgCdTe和QWIPs，以及新型的二类SLs和QDIPs，共四个材料体系。作为
量子点红外光电探测器技术的发展 （学术前沿专题） 专业：测试计量技术及仪器 班级：硕研22班 学生学号： S0908******* 学生姓名：李刚
量子点红外光电探测器 目前大多数红外焦平面阵列（FPA）都以量子阱红外光电探测器（QWIP）或碲镉汞（MCT）光电探测器为基础，而这两类探测器都存有重大的不足。 QWIP对垂直入射光的探测效率很低，因为垂直方向上光子的跃迁被禁止。尽管利用光栅可以弥补这一缺点，但光栅的制作无疑会增加系统的成本。另外，QWIP在高温工作时暗电流较高，所以通常采用冷却方式使其在低温下工作，这便大大增加了成像系统的成本、体积和功耗。 MCT光电探测器则因为MCT固有的不稳定性，很难实现高度均匀的探测器阵列，而且以MCT为基础的FPA还具有成本高和效率低的缺点。 近年来，量子点红外光电探测器（QDIP）在工作温度和量子效率方面取得的重大进步，将有望引领新一轮成像技术热潮，并将在医学与生物学成像、环境与化学监测、夜视与太空红外成像等领域开辟新的应用天地。目前，通过采用纳米技术形成量子点，研究人员已经在开发室温或接近室温工作的高性能成像器方面迈出了一大步。 量子点又称“人造原子”，目前量子点作为提高电子与光电子器件性能的一种手段，已经被广泛应用。量子点的尺寸很小，通常只有10nm，因此其具有独特的三维光学限制特性。将量子点应用在红外光电探测器上，可以使探测器在更高的温度下工作。 开发高温工作的红外光电探测器，可以降低红外成像系统的成本，减小重量，提高效率，这将极大地拓展红外光电探测器的应用范围。研究人员已经开发出了首个以QDIP为基础的焦平面阵列。
国际光学与光子学会SPIE简介 SPIE成立于1955年，致力于推动以光为基础的技术，服务了超过170个国家。SPIE 每年组织或赞助近25个大型技术论坛、展览以及培训项目，范围遍及北美、欧洲、亚洲及澳洲。 1957年，出版了第一期SPIE报刊，举办了第一届国家技术研讨会。 1960年，SPIE报刊刊登了第一组技术论文。 1963年，SPIE举办了第一届研讨班形式的会议并出版了第一批会议记录。 1973年，总部从Redondo Beach迁往加州的Palos V erdes。 1975年，协会收入达到50万美元，实现了财政自给。 1977年，成立了协会金牌奖。总部迁往华盛顿Bellingham。 1995年，举办了成立40周年庆典。合作赞助了在西安举办的国际传感器应用与电子器件展览会。 2000年，SPIE会员Zhores I. Alferov因在半导体异质结构和高速光电子学方面的贡献获得诺物理学奖。 2003年，SPIE数字图书馆启动，提供了期刊和会议纪要的七万篇文献。 现在的光学和光电子学大都围绕信息光学展开研究。在集成光信息处理方面，有光计算、光学互连、衍射光学等前沿领域；在成像方面，较热门的技术有光学计算机断层成像和三维共焦成像系统；在光学传感器方面，人们越来越关注三维传感技术；新一代的全息术和光学信息处理技术也亟待开发。同时，信息光学的材料和装置也成为了热门领域。更加偏向应用领域的还有人机接口与显示技术。当然还有很多基础理论问题，如非线性光学、超快光学现象、散射、位相共轭等。 Statement of Purpose SPIE is an international society advancing an interdisciplinary approach to the science and application of light. About the Society SPIE is the international society for optics and photonics founded in 1955 to advance light-based technologies. Serving approximately 180,000 constituents from more than 170 countries, the Society advances emerging technologies through interdisciplinary information exchange, continuing education, publications, patent precedent, and career and professional growth. SPIE annually organizes and sponsors approximately 25 major technical forums, exhibitions, and education programs in North America, Europe, Asia, and the South Pacific. In 2010, the Society provided more than $2.3 million in support of scholarships, grants, and other education programs around the world.
光电探测器 摘要 本文研究了近期崛起的高科技新秀：光电探测器。本文从光电探测器的分类、原理、主要参数、典型产品与应用、前景市场等方面简单介绍了光电探测器，使大家对光电探测器有一个初步的理解。了解光电探测材料的原理不仅有利于选择正确适宜的光电探测材料，而且对研发新的光电探测器有所帮助 一、简单介绍引入 光电探测器是指一类当有辐射照射在表面时，性质会发生各种变化的材料。光电探测器能把辐射信号转换为电信号。辐射信号所携带的信息有：光强分布、温度分布、光谱能量分布、辐射通量等，其进过电子线路处理后可供分析、记录、储存和显示，从而进行探测。 光电探测器的发展历史： 1826年，热电偶探测器→1880，金属薄膜测辐射计→1946，热敏电阻→20世纪50年代，热释电探测器→20世纪60年代，三元合金光探测器→20世纪70年代，光子牵引探测器→20世纪80年代，量子阱探测器→近年来，阵列光电探测器、电荷耦合器件（CCD） 这个被誉为“现代火眼金睛”的光电探测材料无论在经济、生活还是军事方面，都有着不可或缺的作用。 二、光电探测材料的分类。 由于器件对辐射响应的方式不一样，以此可将光电探测器分为两大类，分别是光 1
子探测器和热探测器。 ○1光子探测器：光子，是光的最小能量量子。单光子探测技术，是近些年刚刚起步的一种新式光电探测技术，其原理是利用新式光电效应，可对入射的单个光子进行计数，以实现对极微弱目标信号的探测。光子计数也就是光电子计数，是微弱光（低于10－14W）信号探测中的一种新技术。 ○2利用光热效应制作的元件叫做热探测器，同时也叫热电探测器。（光热效应指的是当材料受光照射后，光子能量会同晶格相互作用，振动变得剧烈，温度逐渐升高，由于温度的变化，而逐渐造成物质的电学特性变化）。 若将光电探测器按其他种类分类，则 按应用分类：金属探测器，非成像探测器（多为四成像探测器），成像探测器（摄像管等）。 按波段分类：红外光探测器（硫化铅光电探测器），可见光探测器（硫化镉、硒化镉光敏电阻），紫外光探测器。 2
摘要：本文介绍了光纤传感器与传统传感器的优点及传光、传感型光纤传感器的原理。之后 讲述了光纤传感器的分类及其特点，最后重点讲述了光纤传感器的应用，主要有在结构工程 检测方面、在桥梁检测方面、在岩土力学与工程方面、在食品工业中、军事技术。 关键字：光纤传感器原理军工应用工程检测 Abstract: This paper mainly introduces the advantages of the optical fiber sensor and the traditional sensor as well as the principles of the optical fiber sensor, including the type of light and the type of sensor. Besides, it describes the classification and features of the optical fiber sensor. At last, the paper focuses on the application of the optical fiber sensor, mainly in the aspects of structural engineering detection, bridge detection, rock-soil mechanics and engineering, food industry and military technology. Keywords: the optical fiber sensor; principle; military application; engineering detection 1.引言 光纤传感技术的发展始于20世纪70年代，是光电技术发展最活跃的分支之一[1]。近年来传感器产品收益日益增大，传感技术已成为衡量一个国家科学技术的重要标志。光纤传感器与传统的各类传感器相比，可用光作为敏感信息的载体，用光纤作为传递敏感信息的媒质，具有光纤及光学测量的特点，电绝缘性能好，抗电磁干扰能力强，非侵入性，高灵敏度，容易实现对被测信号的远距离监控，耐腐蚀，防爆，光路有可挠曲性，便于与计算机联接。因此光纤传感技术发展迅速，种类多样，被测物里量达70多种。基于相位调制的高精度、大动态光纤传感器也越来越受到重视，光纤光栅、多路复用技术、阵列复用技术使光纤传感器的应用范围和规模大幅度提高，分布式光纤传感器和智能结构更是当今的研究热点[2]。 2.原理 光纤传感器主要由光源、光纤、敏感元件、光电探测器和信号处理系统等部分组成，如图 1 所示[3]。由光源发出的光经光纤引导至敏感元件，光的某一性质在这里受到被测量调制，已调光经接收光纤耦合到光电探测器，使光信号变为电信号，最后经信号处理系统处理得到被测量。
收稿日期:2008-09-24 作者简介:王忆锋(1963-),男,湖南零陵人,高级工程师.曾在美国内布拉斯加大学林肯分校计算机系做国家公派访问学者.目前主要从事器件仿真研究. 文章编号:1673-1255(2008)06-0031-05 量子线红外光子探测器的研究进展 王忆锋 (昆明物理研究所,云南 昆明 650223) 摘 要:基于半导体量子线子能带间跃迁的量子线红外光子探测器(Q RI P )由于其独特的电子性质,具有工作温度较高、信噪比较高、暗电流较低、光谱范围较宽以及垂直入射光响应等特点.对于新型红外探测器的研发而言,Q RI P 是颇具潜力的候选者之一.通过对近年来部分相关文献的分析介绍,总结和评述了Q RI P 制备工艺、物理性质、仿真方法等方面的研究进展.关键词:量子线;量子线红外光子探测器;光子探测器;红外探测器中图分类号:O471.1 文献标识码:A R ecent Developments of Q uantum Wire Infrared Photodetectors WAN G Y i 2feng (Kunming Institute of Physics ,Kunming 650223,China ) Abstract :The quantum wire infrared photodetectors (QRIP )are based on intersubband transitions in semicon 2ductor quantum wires and have the potential for higher operational temperature ,increased signal 2to 2noise ratio ,reduced dark current ,wider spectral range and sensitivity to normal incident radiation due to their unique elec 2tronic properties.It is one of the potential candidates for the developments of new infrared detectors.The devel 2opments of QRIP in the fabrication process ,physical features and simulation methods are summarized and re 2viewed according to the published information in recent years. K ey w ords :quantum wire ;quantum wire infrared photodetector ;photodetector ;infrared detector 在半导体理论中,将电子在各个方向均可以自由运动的结构称为三维结构,例如体材料.当电子在一个或几个方向的运动被限制在小于100nm 的范围内时,将出现量子尺寸效应,即形成一系列离散量子能级.电子在一个方向受限的结构称为量子阱;在2个方向受限的结构称为量子线;在3个方向受限则称为量子点,如图1所示.这些结构通常称为低维量子结构.由于其中至少有一个方向的尺寸小到纳米尺度(0.5～100nm ),故也称为低维纳米结构. 能量状态密度D (E )定义为单位能量变化区域内的能量状态数.D (E )随维数的变化如图1所示,随着维数的降低,连续能带消失,直至量子点中出现完全分立的能级.低维量子结构与体材料在D (E )上的差异,导致了它们电子性质上的不同.例如,与 体材料和量子阱相比,量子线在能带边上具有更加尖锐的电子态密度,这一点有望使量子线获得较高的量子效率,激发了人们对于量子线红外光子探测器(quantum wire infrared photodetector ,QRIP )的研究兴趣.QRIP 的发展潜力包括较高的工作温度、信噪比增加、暗电流降低、光谱波段较宽、以及垂直入射光响应等[1-3].以下介绍了近年来有关QRIP 的研究进展. 1 QRIP 的制备工艺 QRIP 可以利用Ⅲ-Ⅴ族、Ⅳ族或Ⅱ-Ⅵ族半 导体制成[1].图2为一种QRIP 的结构示意图,器件包含由一段量子线有源区和一段量子线势垒区构成 第23卷第6期2008年12月 光电技术应用 EL ECTRO -OPTIC TECHNOLO GY APPL ICA TION Vol.23,No.6December.2008
二、学习要求 1、知道有关光的本性的认识发展过程：知道牛顿代表的微粒、惠更斯的波动说一直到光的波粒二象性这一人类认识光的本性的历程，懂得人类对客观世界的认识是不断发展不断深化的。 2、知道光的干涉：知道光的干涉现象及其产生的条件；知道双缝干涉的装置、干涉原理及干涉条纹的宽度特征，会用肥皂膜观察薄膜干涉现象。知道光的衍射：知道光的衍射现象及观察明显衍射现象的条件，知道单缝衍射的条纹与双缝干涉条纹之间的特征区别。 3、知道电磁场，电磁波：知道变化的电场会产生磁场，变化的磁场会产生电场，变化的磁场与变化的磁场交替产生形成电磁场；知道电磁波是变化的电场和磁场——即电磁场在空间的传播；知道电磁波对人类文明进步的作用，知道电磁波有时会对人类生存环境造成不利影响；从电磁波的广泛应用认识科学理论转化为技术应用是一个创新过程，增强理论联系实际的自觉性。知道光的电磁说：知道光的电磁说及其建立过程，知道光是一种电磁波。 4、知道电磁波波谱及其应用：知道电磁波波谱，知道无线电波、红外线、紫外线、X 射线及γ射线的特征及其主要应用。 5、知道光电效应和光子说：知道光电效应现象及其基本规律，知道光子说，知道光子的能量与光学知识点其频率成正比；知道光电效应在技术中的一些应用 6、知道光的波粒二象性：知道一切微观粒子都具有波粒二象性，知道大量光子容易表现出粒子性，而少量光子容易表现为粒子性。 光的直线传播．光的反射 二、光的直线传播 1．光在同一种均匀透明的介质中沿直线传播，各种频率的光在真空中传播速度：C ＝3×108m/s ； 各种频率的光在介质中的传播速度均小于在真空中的传播速度，即 v