共查询到18条相似文献,搜索用时 140 毫秒
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为实现光反馈机理下激光自混合干涉信号相位的精确提取, 本文提出了一种基于经验模态分析(EMD)的方法.首先, 采用EMD算法对含噪的自混合干涉信号进行了降噪预处理, 提取有效的干涉信号.然后在对含有外腔物体运动信息的光反馈相位求解的过程中, 利用希尔伯特黄变换(HHT)原理实时提取每一时刻的瞬时相位, 将其去包裹处理后得到真实相位. 在弱、适度、强光反馈条件下, 分别对基于EMD的相位提取算法进行了仿真研究.最后, 搭建了基于自混合干涉效应的微位移测量实验平台, 进行实验研究.实验结果表明, 利用该方法可以实现对自混合干涉信号的相位提取, 最大误差小于1.6 rad.仿真和实验结果的一致性, 说明了EMD方法的有效性. 相似文献
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基于半导体激光器的自混合干涉效应,通过实验研究了扬声器的振动特性。实验中,用粘在扬声器振膜上的反射镜作为目标物体(该反射镜的反射率为95%,扬声器用50Hz的正弦波驱动),然后通过条纹计数法获得扬声器的振幅。实验结果表明,在一定范围内,扬声器的振幅与驱动电压呈线性关系。该实验装置极其简单紧凑,自混合干涉信号也十分清晰,实验方法迅速,价格低廉,易实现,而且不需要专用电源,也不需要其他的光学仪器,这一系列优点充分表明自混合干涉技术在振动测量领域具有广阔的发展前景。 相似文献
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针对光纤激光器自混合干涉传感应用,研究了光纤激光器自混合干涉特性,运用四镜法布里-珀罗腔模型对掺铒线形腔光纤激光器自混合干涉效应进行了理论分析,对不同反馈水平下的自混合干涉信号进行了数值模拟,获得了光反馈条件下光纤激光器输出特性.外腔长度的改变会调制激光器的输出强度,外腔长度变化半个波长,对应一个干涉条纹,弱反馈条件下,由反馈引起的激光器的频率变化可以忽略.设计了基于光纤激光器的自混合干涉实验,实验结果和理论分析相符合.此研究结果为进一步开展光纤激光器的自混合干涉传感应用研究奠定了理论与实验基础. 相似文献
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基于激光自混合干涉技术的特点,设计了一种新型半导体激光自混合干涉测振仪系统。系统将频率调制引入自混合干涉中,实现对振动物体的非接触式测量。介绍了激光自混合干涉测振仪的原理、仪器系统的光路系统设计、信号的调制模块设计、解调模块设计以及DSP系统的采集处理模块设计。该仪器体积小、成本低、易于准直、可以非接触式测量,能够测量振动频率在50kHz内的物体,其中包括非周期性振动。可以测量出振动物体的振动频率、振幅以及还原振动波形,振动幅度测量精度可以达到0.325μm,频率精度为1Hz。 相似文献
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用振动激励信号做频率电压变换的倒相触发信号,可以从激光二极管自混合干涉信号还原扬声器谐振时的振动波形,输出信号的振幅与扬声器的振幅成正比. 用正弦波、方波和三角波信号分别激励扬声器,利用自制的激光二极管自混合干涉实验仪观测了的扬声器振动特性,测量了扬声器的谐振曲线. 相似文献
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We present a simple but effective method for small-angle measurement based on optical feedback interferometry (or laser self-mixing interferometry). The absolute zero angle can be defined at the biggest fringe amplitude point, so this method can also achieve absolute angle measurement. In order to verify the method, we construct an angle measurement system. The Fourier-transform method is used to analysis the interference signal. Rotation angles are experimentally measured with a resolution of 10^-6 rad and a measurement range of approximately from -0.0007 to +0.0007 rad. 相似文献
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Liang Lu Longhua Zhai Ke Zhang Jijun Dai Jun Zhu Shenglai Zhen Benli Yu 《Optik》2011,122(20):1840-1842
Laser interferometry based on self-mixing effect widely used to measure displacement, velocity, vibration and distance due to compactness, non-contact, as well as low cost. An important use of the self-mixing effect inside a laser diode is in optical self-mixing vibrometer. We have experimentally investigated self-mixing interference produced by the feedback of light from a vibrated target into a vertical-cavity surface-emitting laser for sensing applications. In this paper, the self-mixing vibrometer employing different feedback regime is discussed and a theoretical analysis is also proposed. Numerical analysis focused on the distortion self-mixing waveform. Numerical analysis and experimental results show that mode-hop occurs when the laser self-mixing vibrometer employing at high feedback level. 相似文献
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We demonstrate the influences of optical feedback from an external mirror with high reflectivity in a He-Ne laser on self-mixing interference fringes and laser polarization states. When the external mirror is tilted to a certain level, the stable and uniform nanometer resolution fringes are generated. The fringe density is 40 times than that of the conventional self-mixing interference or two beam interference, and has still potential to be improved. Each self-mixing interference fringe corresponds to λ/80 displacement of the external mirror, i.e. 7.91 nm displacement of the external mirror. Moreover, when the movement direction of the external mirror is changed, the polarization flipping between two eigenstates will happen. The potential applications of the results are also discussed. 相似文献
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激光回馈效应及其传感应用研究的进展 总被引:4,自引:1,他引:4
对基于激光回馈效应的传感应用研究进展进行了综述。由于激光回馈引起激光器功率波动一个条纹对应外部反射镜移动半个光波波长,功率波动深度与传统双光束干涉系统相当,基于该现象的激光回馈干涉仪与传统的干涉仪相比具有相同的相位灵敏度。但其结构简单、紧凑、易准直的特点,引起了国内外科研者浓厚的兴趣,开发了很多全新概念、经济实用的精密测量仪器。对激光回馈效应在位移测量、速度测量、振动测量、距离测量、角度测量和形貌测量中的原理进行了介绍,同时对各传感应用系统进行了评述。 相似文献
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A new method of using time-averaged digital speckle pattern interferometry for the quantitative measurement of vibration amplitude was developed. Signal processing techniques especially the Hilbert transformation for quantitative evaluation of the Bessel fringes obtained in time-averaged digital speckle pattern interferometry were explored. The quadrature signal after Hilbert transformation is equivalent to a 90° phase-shifted interferogram for a monotonically increasing or decreasing phase function. An algorithm was developed for Bessel fringe contrast enhancement and phase extraction. The techniques were tested numerically and experimentally. Sub-fringe quantification of the time-averaged vibration fringes is realised with the proposed method. Compared with the commonly used phase shift method which requires a minimum of two images for image processing, this method requires only one fringe pattern for data extraction. 相似文献
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Digital holography is a widely used method for displacement measurement in coherent optical metrology. An obvious limit of the method is that too large displacements result in dense fringes, so the fringes are practically invisible. The maximum number of contour fringes in displacement measurement is limited, because the cameras are discrete devices and sampling theory plays an important role. Because of the limited measurement range, compensation methods are promising tools for practical measurements. It can be shown that the practical measurement range can be extended above the Nyquist sampling limit. Compensation methods can be digital, because digital holographic interferometry operates with images recorded with a digital camera. In our research work the upper measurement range of fringe compensation method was examined. Our goal was to perform automatic compensation even if the displacement is higher than the measurement range of the basic method. The operation of the automatic fringe compensation method was based on the combination of two types of out-of-plane displacement measurements with different sensitivities. 相似文献
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《中国光学快报(英文版)》2020,(5)
In order to achieve the accurate measurement of displacement, this Letter presents a self-mixing interference displacement measurement method suitable for the speckle effect. Because of the speckle effect, the amplitude of the self-mixing interference signal fluctuates greatly, which will affect the measurement accuracy of displacement. The ensemble empirical mode decomposition is used to process the interference signal, which can filter out high-frequency noise and low-frequency noise at the same time. The envelope of the self-mixing interference signal is extracted by Hilbert transform, and it is used to realize the normalization of the signal. Through a series of signal processing, the influence of speckle can be effectively reduced, and the self-mixing interference signal can be transformed into standard form. The displacement can be reconstructed by fringe counting and the interpolation method. The experimental results show that the method is successfully applied to the displacement measurement in the presence of speckle, which verifies the effectiveness and feasibility of the method. 相似文献
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仿真分析测量参数对光反馈自混合信号的影响 总被引:1,自引:0,他引:1
针对含有光反馈的半导体激光器,在外腔波动条件下,研究其光反馈干涉自混合信号模型。经计算仿真分析,得到了外腔运动参数及激光器本身参数的变化对光反馈自混合信号波形的影响规律。结果表明,利用光反馈自混合干涉效应可以进行多参数传感测量。 相似文献