共查询到19条相似文献,搜索用时 437 毫秒
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基于白光干涉测量色散补偿薄膜的群延迟色散 总被引:2,自引:0,他引:2
为精确测量超快激光色散补偿薄膜的群延迟色散,提出了一种基于窗口傅里叶变换和样条插值去噪算法的新型白光干涉测量方案。计算机模拟表明此方法测试精度可达0.58fs2。分析了高斯噪声和光强平均效应对测试精度的影响,并使用此方法对实验制备的Gires-Tournois干涉反射镜和啁啾镜进行了测试,在宽光谱范围内测试误差小于10fs2。该方法相比其他算法可以更快速、更精确地实现薄膜相位信息的提取,具有更高的测试精度和实用性。 相似文献
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光波场的相干性(上) 总被引:1,自引:0,他引:1
本文给出了描述光场相干性的基本物理量.从迈克尔逊干涉实验出发,讨论了时间相干性.以矩形谱线的光源为例,计算了时间相干度.简要介绍了傅里叶变换光谱学原理.同时从杨氏干涉实验出发,讨论了空间相干性、准单色光的干涉以及相干性的传播规律及其在迈克尔逊测量干涉仪上的应用. 相似文献
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傅里叶变换光谱仪通过获取待测光的干涉信号来反演光谱信息,是重要的光谱测试与分析仪器。受光电探测电路不稳定、干涉模块装调不到位等因素的影响,傅里叶变换光谱仪获得的干涉光谱信号会出现漏采点、过饱和点、噪声点等无效数据点,导致反演的光谱信号出现失真。为此,研究了一种基于小波变换的干涉光谱信号检测方法,该方法能够快速有效地定位干涉信号中多种无效数据点的位置;在此基础上,研究了干涉光谱信号的校正方法,根据无效点所在区间段的信号特征,通过样条插值方法进行数据拟合,校正干涉光谱信号。通过仿真验证了本方法的可行性;搭建了近红外波段傅里叶变换光谱实验系统,并基于该系统进行验证性实验,对获得的干涉信号进行检测与校正,提高了反演光谱信号的准确性。 相似文献
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色散、群速与群折射率 总被引:3,自引:2,他引:1
本文讨论了群折射率存在的物理意义,指出群折射率不仅包含了折射率概念而且还体现了折射率的色散性质,同样能作为材料本身的光学性质参量.接着指出在折射率的白光干涉法测量中存在着忽视色散作用而导致的将群折射率误认为折射率的情况.将群折射率与折射率区别开来,不仅可以消除折射率测量中所存在的错误,而且可以突出色散现象在光传播时间特性上的意义.为此建立了折射率与群折射率的相互变换关系,通过对于典型物质的折射率与群折射率变换关系的计算,说明二者在数值上的差别甚至对于气体介质来说也是不能忽略的. 相似文献
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本文讨论了群折射率存在的物理意义,指出群折射率不
仅包含了折射率概念而且还体现了折射率的色散性质,同样能作为材料本身的光学
性质参量.接着指出在折射率的白光干涉法测量中存在着忽视色散作用而导致的将群折射率
误认为折射率的情况.将群折射率与折射率区别开来,不仅可以消除折射率测量中所存在的
错误,而且可以突出色散现象在光传播时间特性上的意义.为此建立了折射率与群折射率的
相互变换关系,通过对于典型物质的折射率与群折射率变换关系的计算,说明二者在数值上
的差别甚至对于气体介质来说也是不能忽略的. 相似文献
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Sanjit K. Debnath Mahendra P. Kothiyal Seung-Woo Kim 《Optics and Lasers in Engineering》2009,47(11):1125-1130
Spectral phase in a white-light interferogram contains information about the absolute optical path difference (OPD) in the interferometer. Evaluation of spectral phase is therefore important in applications such as profilometry with white light. In spectrally resolved white-light interferometry (SRWLI) the white-light interferogram is spectrally decomposed by a spectrometer in order to determine this phase. Several single-frame techniques in SRWLI have been proposed for the evaluation of the phase including Fourier transform, Hilbert transform, spatial phase shifting, windowed Fourier transform and wavelet transform. In this paper we present a comparative study of these techniques in this application in relation to the temporal phase-shifting technique which is a multi- frame method. Further, we also propose a modified method to remove the influence of source spectrum modulation in Hilbert transform procedure. 相似文献
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According to the phase shift response of a ring resonator, the role of a fiber-optic ring resonator as a multi-path light-wave circuit in white-light fiber-optic interferometric sensors is analyzed. Formulas related to the maximum intensity of the interference fringes and the system parameters are derived by exact mathematic deduction. The main factors affecting the multiplexing capability of the sensor array are discussed. The analysis method not only gives an explicit explanation for the enhancement of multiplexing capability but also can be applied to other structural white-light sensor systems, in which the ring resonator is used as a multi-path light-wave circuit. 相似文献
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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1 nm,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
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We describe a method for time-domain surface profile measurements via white-light reflection spectroscopy using a hyperspectral Fourier transform spectrometer (HS-FTS). This technique measures the frequency of the spectral modulation of reflected light from a multilayer optical surface and reports the spatially resolved optical thickness. Owing to the Fourier relationship, the Fourier transform spectrometer manifests this spectral modulation as temporal satellites in interferogram space. We show that measurement of the positions of these satellites can be used to reconstruct the optical thickness profile over a surface using the HS-FTS. 相似文献
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White-light interferometric techniques have been widely used in three-dimensional (3D) profiling. This paper presents a new method based on vertical scanning interferometry (VSI) for the 3D profile measurement of a micro-component that contains sharp steps. The use of a white-light source in the system overcomes the phase ambiguity problem often encountered in monochromatic interferometry and also reduces speckle noises. A new algorithm based on the continuous wavelet transform (CWT) is used to retrieve the phase of an interferogram. The algorithm accurately determines local fringe peak and improves the vertical resolution of the measurement. The proposed method is highly resistant to noise and is able to achieve high accuracy. A micro-component (lamellar grating) fabricated by sacrificial etching technique is used as a test specimen to verify the proposed method. The measurement uncertainty of the experimental results is discussed. 相似文献
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We demonstrated a spectrometer that is capable of acquiring the spectra from interferometric fiber-optic sensors at high speed. The high spectrum acquisition rate is enabled by transforming the spectral information from frequency domain to time domain using a dispersive element and high-speed data acquisition devices. Preliminary results show that the prototype system can record 10,000 frames of spectra per second and achieve a spectrum measurement resolution of 15 nm. Better performance could be realized by using a Raman amplifier and by optimizing the parameters of the system and data processing methods. 相似文献
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We present a simple white-light spectral interferometric technique employing a low-resolution spectrometer for a direct measurement
of the group dispersion of optical components over a wide wavelength range. The technique utilizes an unbalanced Mach-Zehnder
interferometer with a component under test inserted in one arm and the other arm with adjustable path length. We record a
series of spectral interferograms to measure the equalization wavelength as a function of the path length difference. We measure
the absolute group refractive index as a function of wavelength for a quartz crystal of known thickness and the relative one
for optical fiber. In the latter case we use a microscope objective in front and a lens behind the fiber and subtract their
group dispersion, which is measured by a technique of tandem interferometry including also a Michelson interferometer. 相似文献