共查询到20条相似文献,搜索用时 62 毫秒
1.
提出了一种新型的基于可编程MEMS(micro-electro-mechanical systems)微镜的微型傅里叶变换红外光谱仪.该光谱仪采用可编程MEMS微镜和倾斜反射镜替代了传统傅里叶变换光谱仪的动镜系统.理论分析了该光谱仪的工作原理,并进行了计算机仿真,验证了该方法的可行性.结果表明,该光谱系统能够准确地还原光谱信息,其光谱分辨率在近红外区域小于5 nm,波长准确性约1nm,系统理论上的信号采集周期约50 ms.适合于利用阿达玛变换提高信噪比,可应用于微量物质检测. 相似文献
2.
微型近红外光谱仪分析系统的研制 总被引:1,自引:0,他引:1
近红外光谱技术足光谱测试技术、化学计量学技术与计算机技术的有机结合,文章立足于食品有效成分无损定量检测的目标,介绍了微型近红外光谱分析系统的研制过程.作为系统测试的基础,文章重点研究了适用于在线实时分析的微型化近红外光谱仪,研制出的微型近红外光谱仪样机工作波长:850~1690nm,分辨率小于10 nm.通过对样机主要参数的测试表明,性能接近国外同类产品水平.另外,化学计量学与计箅机技术的结合是系统的核心,提出了基于最小二乘的局部加权回归(LS-LWR)的建模方法.最后,应用研制出的系统对葡萄糖水溶液定量测试实验表明,其预测集的相关系数达到了0.995,预测标准偏差为0.06. 相似文献
3.
近红外微型光谱仪光学系统设计与模拟 总被引:3,自引:0,他引:3
基于光谱仪基本工作原理和光学设计理论,以系统微型化、且能满足一定光谱范围和分辨率要求为具体设计目标,提出了基于平面衍射光栅分光的交叉式C-T结构的近红外微型光谱仪光学系统结构方案.采用ZEMAX软件对近红外微型光谱仪的分光系统、成像系统进行了优化设计与模拟分析.最终设计与模拟分析结果表明,该光学系统光谱范围为900~1 700 nm,分辨率<10 nm,谱面展宽为12.74 mm,F数为8.128 388,系统体积为51.26 mm×41.81mm×22 mm. 相似文献
4.
近红外光谱分析技术在航空航天、生物医药、环境检测、食品安全等众多领域均有广泛应用。高性能、微型化、低成本近红外光谱仪是制约基于近红外连续光谱分析的微小型检测装备发展的主要瓶颈,是当前光谱仪发展的主要研究方向。提出了一种基于微光机电系统(Micro-optical electro-mechanical system, MOEMS)集成扫描光栅微镜和改进型非对称式切尼-特纳(Czerny-Turner, C-T)光学结构的微型近红外光谱仪系统结构,分析了光谱仪系统和集成扫描光栅微镜的工作原理,基于光栅相关参数和光谱仪性能指标要求确定了集成扫描光栅微镜最大扫描角度。分析了改进型非对称式C-T初始光学结构像差,基于ZEMAX光学设计平台完成了光谱仪光学系统的仿真和优化设计,确定了系统关键参数。仿真分析了平凸柱面透镜对改进型非对称式C-T光学结构系统分辨率、检测灵敏度等性能参数的影响。基于仿真优化结果,完成了微型近红外光谱仪机械结构设计、加工与装调,搭建实验平台完成了光谱仪相关性能参数测试。结果表明,设计的基于MOEMS集成扫描光栅微镜和改进型非对称式C-T光学结构的微型近红外光谱仪,采用重庆大... 相似文献
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近年来,随着微光机电系统(MOEMS) 技术的快速发展,光谱仪朝着微型化、低成本、高性能方向发展。基于MOEMS技术制作的闪耀光栅可集成于扫描微镜,其作为近红外光谱仪的核心部件,可实现单管探测器代替昂贵的阵列式探测器,以降低近红外光谱仪成本与体积。设计了一种高性能扫描光栅微镜,以提高光谱仪的探测灵敏度。扫描微镜表面集成高衍射效率光栅,背面制作电磁驱动线圈。采用光学软件与有限元方法对器件参数进行优化。仿真结果表明:扫描光栅微镜谐振频率为484.38 Hz,最大扭转角度为4.55,在800~1800 nm工作波长范围内,整体动态衍射效率在54%以上且最大值达90%。 相似文献
6.
WANG Su-hui ZHANG Xu SUN Zhi-shen YANG Jie GUO Teng-xiao DING Xue-quan 《光谱学与光谱分析》2021,41(11):3370-3376
在众多化学物质检测技术手段中,红外检测技术由于具有非破坏性、灵敏度高、检测速度快、准确性好等特点,广泛应用于化工、生物医学、食品安全等领域。量子点光谱仪是使用量子点代替光栅作为分光器件,结合阵列探测器及光谱重构算法实现光谱检测的新型微型光谱仪,具有体积小、成本低等优点。为了进一步提升现有量子点光谱仪和量子点器件检测化学物质的普适性,为微小型近红外分光器件研制提供有效技术途径,以危险化学品乙醇、化学战剂模拟剂甲基膦酸二甲酯、二氯甲烷为目标物,通过将多种量子点材料与紫外固化胶混合后沉积在RGB点阵模块并固化,制备了发射光谱波段为900~1 600 nm的近红外胶体量子点阵列。采用经验模态分解方法提取输入光谱的高频信号以减小随机噪声干扰,并基于最小二乘法建立了相应光谱重构算法。实验结果表明,近红外胶体量子点阵列制备方法简单,成本低、稳定性较好。具有144条光谱通道的近红外胶体量子点阵列实现的重构光谱分辨率可以达到4.861 nm,与标准吸收光谱相比,其特征峰最小偏差仅为0.043%。因此,使用近红外胶体量子点阵列结合光谱重构算法可以实现气态、液态目标物的光谱重构和检测识别。未来,通过增加阵列数量可有效提升重构光谱的光谱分辨率;通过增加所选量子点材料,还可以实现从紫外到红外波段范围内的光谱检测;通过优化检测光路和重构算法参数提高目标物检测信噪比。 相似文献
7.
基于数字微镜技术的阿达玛变换近红外光谱仪 总被引:1,自引:0,他引:1
构建了一个基于数字微镜技术的新型阿达玛变换近红外光谱仪.光学信号采用光纤引入,以光栅作为分光元件,利用数字微镜代替传统的机械式阿达玛模板进行光学编码调制,使用单点InGaAs红外探测器检测调制后的光信号,通过快速阿达玛解码还原出原始光谱.通过实验检验了光谱仪的分辨率、信噪比、稳定性以及谱图获取速度等指标.实验结果表明,... 相似文献
8.
为了提高高端探测器的利用率与增强拉曼光谱仪同时对不同物质检测的适用性,将多个波长激发的拉曼光谱仪集成设计成为一个光谱仪,将具有重要的应用价值。提出了一种基于CT结构双波长(532nm和785nm)激发的双通道拉曼光谱仪设计方法。所采用的这种设计方法基于探测器的工作特点为实现双光路结构同时工作创造了条件,从而最大程度的增加了光谱测量范围,同时该方法也实现了对探测器的有效感光面像元的充分利用并且最大程度地实现了高光谱分辨率。优化结果表明对于532nm的激发波长,分辨率为5cm^(-1)、光谱范围达到80~4200cm^(-1);对于785nm的激发波长,分辨率为3cm^(-1)、光谱范围达到200~2300cm^(-1)。 相似文献
9.
针对传统光谱仪体积大、成本高、检测速度慢、需样品前处理等不足,提出了利用数字微镜面阵(DMD)实现光谱谱面分割分时选通的近红外光谱仪光学系统.首先,对比传统光路介绍单探测器微型光谱仪系统测量原理|然后结合DMD特性提出光路方案,根据几何光学原理进行初步光学元件选型和光路结构设计,利用ZEMAX光学软件对光路进行仿真,确定结构参数|最后,搭建实验平台,进行光路测试.实验结果表明:该系统光路尺寸为70 mm×130 mm,测量波段为(900~1 500 nm),分辨率可达19 nm|在能量损失较小的情况下,减小狭缝尺寸可提高光学分辨率,狭缝的极限尺寸为200 μm|减小狭缝子午面高度可减小谱面内弯曲现象.本系统基本满足近红外分光,实现单点探测器光谱测量的要求. 相似文献
10.
室外BRDF(Bidirectional reflectance distribution function)测量随着遥感的发展越来越重要。室外测量要求测量周期短、测量点多、光谱分辨率高。为了满足这一要求,设计了室外高光谱BRDF自动测量系统。系统主要由自动测量架和光谱仪器组成。测量架半径为2m,主要由天顶弧轨道、方位圆轨道、伺服电机、PLC组成。光谱仪器包括一台亮度计和一台照度计,亮度计测量反射亮度,被固定在测量架小车平台上,照度计测量入射照度。两台光谱仪器采用相同的平场凹面光栅分光、线阵列探测器探测。光谱测量范围为400~2500nm,光谱分辨率为3.5nm(400~1000nm)、12nm(1000~2500nm)。系统在工控机的控制下完成自动测量。在自动默认状态下测量周期大约为10min。 相似文献
11.
A multi-conjugate adaptive optics (MCAO) can offer a possibility of widening field of view (FOV) characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle's expressions of two deformable mirrors (DMs) MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance. 相似文献
12.
Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use. 相似文献
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A.C mismatches are studied by Raman spectral characterization of PolyA, PolyC, and their equimolar complex in solution of 0.14 mol/L Na ,pH7.0.Experimental results show that A·C mismatches occur to be A/B (mainly A) conformers, and unlike Watson-Crick base pairing, this kind of mismatches is stabilized by only one hydrogen bond involving cytosine N4H2 and adenine N7.The formation of A·C complex makes the base stacking interactions much stronger, and conformation of the backbone more ordered, which leads to obvious Raman hypochromic effect with some shifts in corresponding bands. 相似文献
15.
40-GHz clock modulated signal as a pump to improve the efficiency of four-wave mixing (FWM)-based wavelength conversion in a 26.5-km dispersion shifted fiber (DSF) is investigated. The experimental results demonstrate that the conjugated FWM component has higher intensity with the clock pumping than that with the continuous-wave (CW) light pumping. The improvement of FWM-based wavelength conversion efficiency is negligible when the pump power is less than Brillouin threshold. But when the pump power is greater than Brillouin threshold, the improvement becomes significant and increases with the increment of pump power. The improvement can increase up to 9 dB if pump power reaches 17 dBm. 相似文献
16.
References: 《声学学报:英文版》2008,27(1):85-96
Microphone array-based speech enhancement has great importance for speech communications and speech recognition. To reduce the aperture of the microphone array and to increase the effect of the speech enhancement will greatly broaden the application areas of the microphone array. An array crosstalk resistant adaptive noise cancellation method is therefore presented. And then an improved spectral subtraction algorithm is further cascaded to obtain better enhancement results. Theoretic analysis and experiments indicate that the proposed scheme needs only a very small microphone array while it simultaneously achieves a higher SNR improvement. Besides, the proposed scheme can be used in many noisy environments and is easy for real-time implementation. 相似文献
17.
Our experimental results show that the presence of a proper amount of negative group velocity dispersion is essential to multi-pulse operation of a Kerr-lens mode-locked femtosecond laser. We demonstrate that the pulse separations and the number of pulses contained within a cavity round trip are strongly dependent on the initial perturbations. The results allow us to get a better understanding on the influences of the convoluted self-phase modulation and intra-cavity dispersions on the stable multi-pulse oscillation in a Kerr-lens mode-locked femtosecond laser. 相似文献
18.
Based on the Rytov approximation of light propagation in weak turbulent atmosphere,the closed-form expressions of field and average irradiance of each one of the four fundamental families of Helmholtz-Gauss (HzG)beams:cosine-Gauss beams,stationary Mathieu-Gauss beams,stationary parabolic-Gauss beams,and Bessel-Gauss beams,which are propagating in weak turbulent atmosphere,are obtained.The results show that the field and average irradiance can be written as the product of four factors:complex amplitude depending on the z-coordinate only,a Ganssian beam.a factor of complex phase perturbation induced by atmospheric turbulence,and a complex scaled version of the transverse shape of the non-diffracting beam.The effect of weak atmospheric turbulence on irradiance distribution of the HzG beam can be ignored. 相似文献
19.
Xin Kang 《中国光学快报(英文版)》2008,6(2)
An effective method for reducing the speckle noise in digital holography is proposed in this paper.Different from the methods based on classical filtering technique,it utilizes the multiple holograms which are generated by rotating the illuminating light continuously.The intensity images reconstructed by a series of holograms generated by rotating the illuminating light possess different speckle patterns.Hence by properly averaging the reconstructed intensity fields,the speckle noises can be reduced greatly.Experimental results show that the proposed method is simple and effective to reduce speckle noise in digital holography. 相似文献
20.
The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry(SIMS) equipment respectively.It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films.In addition,the difference of Zr content in the two kinds of HfO2 single laver films was much laxger than that of the other impurities such as Ti and Fe.which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2.With these two kinds of HfO2 and the same kind of SiO2.we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm.Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively,which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films. 相似文献