大角孔径声光可调滤光器设计

本文介绍了大角孔径TeO_2晶体声光可调滤光器的设计方法,提出了声入射角θ_α=100°,光入射角θ_(?)=23.4°的新的晶体取向,从实验上证明了该种声光可调滤光器满足准确的切线动量匹配条件,测得的调谐关系与理论值相一致,这种参数的声光可调滤光器其分辨率提高近10(?).经过补偿后的衍射偏转角变化减小到±0.06°.     

1.2-2.5μm可调谐红外声光滤光器

本文介绍以ＴｅＯ２作为声光互作用介质的可调谐声光滤光器,我们举调谐波长为１．２－２．５μｍ红外滤光器为例,介绍了滤光器的设计参数。１．２－２．５μｍ滤光器的调谐曲线,光谱分辨率,以及利用该滤光器研制的红外声光光谱仪对某一种塑料中的两种分子的红外吸收光谱的分辨能力。     

声光滤光器性能指标的计算和讨论

以可调谐声光滤光器为元件所制造的光谱分析仪,利用声光谱光器的电调谐分光作用,辅以计算机控制,以完成信息的实时处理,其中声光滤光器性能指标的好坏将直接影响光谱分析仪的设计制造本文对用不同切向的氧化碲晶体所制成几种声光滤光器的几项性能指标进行计算的讨论,使在设计制造光谱分析仪时对声光谱光器的声光和电性能先有一个总体认识,以减少不必要的实验和摸索。     

声光可调谐滤光器的等值点理论

系统地给出了满足平行切线动量匹配条件下的声光相互作用关系曲线 ,发现仅当光的入射方向与晶体光轴间的夹角约为 5 6°时 ,在可见至近红外光谱范围内 ,同一声波矢量可使o光入射e光衍射和e光入射o光衍射同时满足平行切线动量匹配条件 ,并且这两束衍射光的波长相等。称这一特殊的角度为声光可调谐滤光器理论设计的等值点 ,并通过实验验证了这一分析结果的正确性。应用等值点原理设计声光可调谐滤光器 ,在不降低波长分辨率的前提下可大幅度提高光谱测量的信噪比     

声光可调谐滤光器的光谱传递特性和数据恢复方法

本文在分析声光可调谐滤光器透过特性的基础上。对其引入了光谱传递函数的概念,并计算和讨论了光谱传递函数随滤光器结构参数的变化规律。     

声光可调谐滤光器调谐曲线的测量

声光可调谐滤光器调谐曲线的测量魏爱俭，丁兰英，任诠，安希书（山东大学光电系济南２５０１００）一、引言各向异性介质中的声光互作用现象早在本世纪３０年代就已被发现，但由于声光互作用所引起的光频率和方向变化都很小，没有多少实用价值，长期以来未受到重视．自从...     

声光可调谐滤波器(AOTF)消色散设计

介绍了非共线声光可调谐滤波器的构成及基本原理,计算了非共线声光可调谐滤波器衍射出的±1级衍射偏振光的偏转角,采用在光路中添加光楔的方法补偿非共线声光可调谐滤波器晶体色散引起的图像漂移.分析结果表明使用TeO_2材料设计的光楔在楔角为7.6°的时候可以控制图像漂移在一个像元以内,并在400～900 nm的工作波段范围内满足稳定成像的要求.     

La_3Ga_5SiO_(14)声光可调谐滤波器设计

分析了La3Ga5SiO14(简称LGS)既可以做成同向声光可调谐滤波器,又可以做成大孔径非同向声光可调谐滤波器。推导出超声波频率f和光波波长λo的调谐关系;计算出滤波器的光谱分辨率R和集光能力δiθ;光入射角iθ与衍射角θd、声入射角θa之间的关系。为LGS声光可调滤波器的实用化设计提供了充分可靠的理论依据。把LGS与TeO2声光可调滤波器的光谱分辨率和集光能力做了比较,认为LGS设计成同向声光可调谐滤波器既简便又实用。     

二氧化碲非同向声光可调谐滤波器的设计分析

在分析非同向声光可调谐滤波器器件设计理论的基础上，同时考虑声光晶体的双折射和旋光特征，分析和计算了二氧化碲声光可调谐滤波器的超声波极角θａ和入射光波极角θｉ之间的关系以及超声波频率ｆａ和光波波长λ０之间的调谐关系。     

通信用声光可调谐滤波器

TN65 2004064495 通信用声光可调谐滤波器=Acousto-optic tunable filters used in communication[刊,中]/刘维(北京理工大学信息科学技术学院光电工程系.北京(100081)),崔建民…∥光学技术.—2004,30(4).—394-397 介绍了以LN为基底的集成型和以TeO_2为材料的体型通信用声光可调谐滤波器(AOTF)的工作机制,并对     

Design and analysis of a noncollinear acousto-optic tunable filter

The design of the noncollinear acousto-optic tunable filter (AOTF) is commonly based on the parallel tangents momentum-matching condition. Previous studies either have used an approximation of the birefringence of the interaction material or have ignored the rotatory property of TeO(2). These approaches would obviously decrease the accuracy of designing an acousto-optic tunable filter (AOTF). We introduce an analysis method of calculating the optimum incident optical angle. Besides, an appropriate optical wedge on the output optical facet is designed to reduce the wavelength dependence of the diffracted beam angle, which is very significant in practical applications of AOTF.     

AOTF成像光谱仪光学系统的最优方案选择

基于声光可调谐滤波器（AOTF）的成像光谱仪是一种新型的成像光谱仪,它除了具有一般成像光谱仪的二维空间信息与一维光谱信息外,还能获得目标的偏振信息。在实际应用中AOTF可接收的光束孔径角一般不大于5～6,因而受到所采用声光晶体可接收角度的限制,AOTF光谱成像仪的光学系统不能同时兼顾大孔径与大视场。要求AOTF成像光谱仪视场满足128128像元,TeO2晶体尺寸为10 mm10 mm,根据声光可调谐滤波器成像光谱仪光学系统的特点,分析比较了2种光学系统总体方案,最终将系统的孔径光栏放置在晶体上,TeO2晶体尺寸限制了孔径光栏的尺寸,晶体可接收的角度决定了系统的视场角,提高了能量利用率,获得较高的图像信噪比。     

重离子弹性散射中的角分散研究

简要评述了重离子弹性散射角分散研究的内容、 方法及物理意义。通过前角区重离子弹性散射产物微分截面的角分布测量,作出角分散图ln(dσ/dθ)\|θ2。 分析经典偏转函数, 从而在实验上确定了反应系统的核虹角。 在低能、 重靶的重离子反应系统中, 核虹角远小于擦边角。 晕核及弱束缚核比稳定核具有更小的核虹角和更大的核相互作用范围。 经典偏转函数的计算有助于提供一套光学势参数, 以便于拟合弹性散射产物的微分截面。 In terms of the angular dispersion plot of ln(dσ/dθ) versus θ2, which can be obtained from the angular distribution of the elastic scattering differential cross sections in heavy ion collisions, systematic analysis on the angular dispersions is made by using classical deflection function for the available experimental data on the target of 208Pb. Our systematic analyses bring about some important results. Firstly, there is an angular dispersion turning angle at forward angular range beyond the grazing angle. Secondly, the nuclear rainbow angle for such reaction systems can be determined by measuring differential cross sections of elastic scattering at forward angular range and analyzing the angular dispersion. Thirdly, analysis of angular dispersion may provide a way to determine a set of optical potential parameters by means of fitting the experimental data of elastic scattering differential cross sections. Finally, for the halo nuclei as the projectiles, there is an exotic behaviour, i. e., smaller angular dispersion turning angle.     

Hyperspectral imaging performance of a TeO2 acousto-optic tunable filter in the ultraviolet region

A compact UV hyperspectral imager can be designed with an acousto-optic tunable filter (AOTF) installed in front of an enhanced CCD camera. Tellurium dioxide (TeO2) is the most commonly used crystal for AOTFs from 0.4 to 4 microm. We conducted an experiment to determine the UV spectral response of an imaging TeO2 AOTF in tandem with a known KDP AOTF and obtained good-quality hyperspectral images by using the TeO2 filter down to 365 nm. We compared the performance of the TeO2 filter-based hyperspectral imager with an imager based on a KDP filter because currently the latter is the best available material for the UV, and we found the performance of the TeO2 imager in the range 355-480 nm to be superior to that of a KDP imager. We present our experiments and the results obtained.     

Measurement of Angular Cross Correlation of the Cross Section Fluctuation in Dissipative Collision 27Al+27Al

The excitation function was measured from θ_lab=10.4° to 57.4° in dissipative collision ²⁷Al+²⁷Al with incident energy ranging from 114 to 123 MeV in step of 200 keV. The Angular-cross Correlation Functions (ACFs) of cross section fluctuation within large angle region were obtained through experiment for the first time. It is found that the angular coherent width is at least 40°. It is interesting that the ACFs is not simple bell shape but shows strong asymmetry. The over-all behavior is that ACF varies more quickly for the backward angles. Itis also noticed that the cross section fluctuation in the forward angle region (θ_cm<70°) shows much stronger angular coherence than in the backward angle region (θ_cm>70°). This angular dependence may be attributed to the coherent rotation effect of intermediate dinuclear system.     

O(3P)+H2→OH+H反应的立体动力学研究

利用BMS1势能面[Brandao等,J.Chem.Phys.121,8861(2004)],选取碰撞能为34.6 kcal/mol,用准经典轨线方法研究了O(3P)+H2反应的立体动力学性质.计算并讨论了k与j'的夹角的分布关系P(θr)以及描述k-k'-j'三者关系的二面角分布P((ρ)r).(k)为反应物速度方向,k'为产物的速度方向,j'为产物的角动量方向)P(θr)的峰值在90°附近并且关于90°呈对称性分布,这表明产物角动量的方向与初速度的方向垂直.二面角分布P((ρ)r)关于散射平面呈反对称性分布,这一结果表明产物的角动量具有强烈的极化效应.另外,我们还研究了振动激发对产物角动量的影响,结果表明产物的矢量性质对反应物的初始振动态非常敏感.     

Effects of W and Mo crystalline texture on the angular distribution of sputtered atoms

The effects of W and Mo surface crystalline texture on the angular distribution of sputtered atoms were investigated experimentally and by computer simulation. A small-sized planar DC magnetron was used to sputter the target by 200–300 eV Ar⁺ ions. The crystalline texture was formed under rolling of metal foils and during the preparation of metal bars and was controlled by X-ray diffraction analysis. For W and Mo foils, a strong anisotropy of the angular distribution was found. The character of angular distribution was different in the planes oriented perpendicularly and in parallel to the direction of rolling. In the first case, the angular distribution was peaked at the polar angle θ=0, while in the second case, the angular distribution, in addition to a maximum at θ=0, revealed a pronounced maximum at θ≈ 57° and ≈60° for Mo and W, respectively. For bars, no azimuthal anisotropy was observed, but the angular distribution was peaked at θ=37° (Mo) and θ=45° (W). This is in contrast to the case of non-textured Mo and W polycrystals, for which the angular distribution had a maximum at θ=0. Computer simulation technique in combination with the results of X-ray analysis was used to clarify the above experimental findings. It was demonstrated that the angular distribution of sputtered atoms can be successfully used for the determination of the crystalline texture of metals.     

Tunneling of X-ray photons through a thin film under total internal reflection conditions

Tunneling of 0.154-and 0.139-nm x-ray photons through a thin film under total internal reflection conditions has been experimentally demonstrated. The NiSi₂ film 13 nm thick is deposited by magnetron sputtering on a polished Si substrate. A beam with an angular spread of 20″ is directed to the Si/NiSi₂ interface from the inside through the lateral surface of a sample. A peak associated with tunneling of photons from Si to air through the NiSi₂ film is observed at grazing angles of θ₁ > 0.4θ_c, where θ_c is the critical angle of total internal reflection at the Si/NiSi₂ interface. The integral intensity of tunneling peaks that is measured for various θ₁ angles agrees with the calculations.