共查询到19条相似文献,搜索用时 125 毫秒
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在利用光反馈光腔衰荡技术测量大口径光学元件反射率及其均匀性分布时,需要对光学元件进行二维扫描测量,而在扫描过程中光学元件的倾斜失调将对测量结果造成影响.本文根据失调谐振腔光束传输增广矩阵,通过数值运算模拟了在对称共焦腔和一般稳定腔情况下,光反馈衰荡腔结构中由样品倾斜失调引起的输出腔镜上光斑中心位置变化以及对反射率测量的影响.仿真结果表明:对称共焦腔情况下,输出腔镜上奇数次光斑无漂移,偶数次光斑漂移量为固定值|在一般稳定腔情况下,输出腔镜上奇偶数次光斑均往复振荡漂移.分析表明,该系统对样品失调角度的敏感程度与样品在腔内的位置以及腔长有关,通过改变样品在腔内位置,选择适当腔长以及包络拟合法可以减小样品失调对测量结果的影响. 相似文献
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带高斯镜的热透镜谐振腔的光腔特性及动力学稳定性 总被引:1,自引:0,他引:1
建立了带高斯镜的热透镜谐振腔的光学矩阵,分析了谐振腔的稳定性条件及腔内高斯光束的传输特征,通过研究光腔特征参数随热透镜变化的动力学特征,探讨了此类谐振腔的动力学稳定性。 相似文献
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无衍射光莫尔条纹被广泛应用在精密测量领域中,实现无衍射光莫尔条纹中心的精确定位是高精度测量的关键。通过对无衍射光莫尔条纹图像特征进行分析,提出了一种无衍射光莫尔条纹的中心定位方法。该方法首先根据光强分布特征,提取莫尔条纹图像中两光斑中心局部同心圆区域;然后进行局部同心圆环检测,确定初始圆心集;再对初始圆心集进行聚类分析确定两光斑中心的初始位置;最后删除异常点并迭代求取两光斑中心较精确的位置,实现无衍射光莫尔条纹两光斑中心的定位目的。理论和实验结果表明该方法能快速、准确地同时确定两光斑中心位置,且误差小于1 pixel。 相似文献
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鉴于单向环形腔是目前获得较大功率单纵模激光最有效的方式之一,为使环形腔单向运行,需要在环形腔内插入对正反2个方向的光产生损耗差的光学元件。采用激光二极管泵浦Nd∶YAG晶体,用声光调制器作为光学二极管使环形腔单向运行,实现四镜矩形环形腔单纵模激光器。实验中谐振腔的稳定性由增益介质的热透镜保证,声光调制器给正反2个方向的光提供损耗差,这使得在竞争过程中有较大损耗的光不能运行从而获得单向输出。实验获得了连续功率1 W、光束质量因子M2为1.21 的1.06 m单纵模激光。 相似文献
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基于谐振腔失调灵敏度参量随腔长的变化关系,提出了一种衰荡腔,它是由共焦腔将腔长缩短为原来的0.73得到的稳定腔。根据光束传输规律和失调腔矩阵方法,以及光腔衰荡法测量原理和曲线拟合方法,建立了腔长、腔镜角度失调下光腔衰荡法的反射率测量模型。通过数值模拟,研究了这种稳定衰荡腔中,腔微小失调对反射率测量结果的影响,并与相同失调情况下共焦衰荡腔的测量结果进行了对比分析。结果表明,这种稳定腔用作衰荡腔,测量结果受腔镜角度失调影响较大,而受腔长失调影响小;其长度较短,便于工程应用;衍射损耗较小,测量精度高。 相似文献
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Waveform Measurement of Ultra-Short Optical Pulses Based on Two-Photon Absorption in Si-Image Sensor
Koichi Aizawa Hiroyuki Aoki Yoshimasa Ito Yosuke Tanaka Takashi Kurokawa 《Optical Review》2005,12(2):122-125
We demonstrate a novel waveform mesurement system of ultra-short optical pulses based on the two-photon absorption process in a Si-image sensor. Using an interferometer with a tilt mirror in the reference path, the relative time difference between the signal and reference pulses is spatially distributed on the Si-image sensor, so the intensity auto-correlation is monitored as an image at a time without using moving parts. This system can create or remove an interference fringe pattern overlapped on the auto-correlation image by controlling the polarization states of the laser pulse, which is useful for measuring the crossing angle between the signal and reference beams as well as avoiding contamination of the interference fringe into the auto-correlation image. We successfully measured optical pulses less than 100 fs from a fiber ring laser with a temporal resolution of 0.4 fs. The obtained waveform agreed well with that observed with a conventional second harmonic generation (SHG) based auto-correlator. 相似文献
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A self-mixing interferometer is proposed to measure nanometre-scale optical path length changes in the interferometer’s external
cavity. As light source, the developed technique uses a blue emitting GaN laser diode. An external reflector, a silicon mirror,
driven by a piezo nanopositioner is used to produce an interference signal which is detected with the monitor photodiode of
the laser diode. Changing the optical path length of the external cavity introduces a phase difference to the interference
signal. This phase difference is detected using a signal processing algorithm based on Pearson’s correlation coefficient and
cubic spline interpolation techniques. The results show that the average deviation between the measured and actual displacements
of the silicon mirror is 3.1 nm in the 0–110 nm displacement range. Moreover, the measured displacements follow linearly the
actual displacement of the silicon mirror. Finally, the paper considers the effects produced by the temperature and current
stability of the laser diode as well as dispersion effects in the external cavity of the interferometer. These reduce the
sensor’s measurement accuracy especially in long-term measurements. 相似文献
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针对现有光学玻璃弹性模量测量周期长、测量过程复杂等问题,提出了一种利用计算机图像处理技术快速测量小样品光学平板玻璃弹性模量的方法。基于接触力学理论和牛顿环干涉原理推导出测量光学玻璃弹性模量的解析式,利用图像处理技术的优势,通过摄像头拍摄牛顿环干涉图像,设计MFC监控与单张图片拍摄界面程序,自动测量牛顿环干涉图像中心黑斑半径,最后根据光学玻璃弹性模量与牛顿环干涉图像中心黑斑半径及牛顿环中心应力之间的关联关系,实现小样品光学玻璃弹性模量的快速测量。实验结果表明:在应力31.17 N~55.11 N范围内,光学玻璃弹性模量的测量相对误差不超过±8.8%;在应力55.11 N~71.07 N范围内,测量相对误差不超过±16%。 相似文献
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The anti-misalignment stability and output characteristics of the right angle cone cavity laser are experimentally studied. When the misalignment angle of the cone mirror turns to 46.8 minutes, the single-pulse output energy of the plano-cone cavity laser decreases 24% and the near-field beam patterns have little change; as for the beam directional stability, when the measuring place stands 3.12 m in front of the output mirror, the near-field beam patterns of the plano-cone laser are located at the primary places until the misalignment angle of the cone mirror turns to 18 minutes. These results show that the plano-cone cavity laser has better performances in comparison with the plano-concave cavity laser. The analytical results of the mode instrument are also obtained, which show that the near-field beam intensity distribution of the plano-cone mirror cavity laser is near to the plane wave. 相似文献
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Xiangzhi Bai 《Optik》2013,124(24):6727-6731
Impulsive noise removal is an active research area in optical signal processing. Morphological operators have been tried for impulsive noise removal. However, the performance is not very effective. Dual hit-or-miss transforms could identify the protruding bright or dark pixels like impulsive noise pixels in image, which may be used to construct effective algorithm for impulsive noise removal. In this paper, an algorithm based on the multi scale dual hit-or-miss transforms is demonstrated. Firstly, the positive impulsive noise pixels, which are bright pixels, are identified by multi scale hit-or-miss transform. Then, the negative impulsive noise pixels, which are dark pixels, are identified by multi scale dual hit-or-miss transform. Finally, the identified impulsive noise pixels are removed and replaced by a reasonable value estimated by adaptive median filter. Experimental results show that, because the multi scale dual hit-or-miss transforms could effectively and correctly identify the impulsive noise pixels, the noise pixels are correctly removed and the real image details could be well maintained. 相似文献
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Lizhi Dong Wenjin Liu Ping Yang Bing Xu Xiang Lei Yu Ning Hu Yan 《Optics Communications》2011,284(7):2003-2006
Misalignment of a laser cavity would result in the displacement of beam location on the cavity mirrors. We present a simple method for automatic cavity alignment of a solid-state laser through detecting the location of the laser beam on the rear mirror, with which neither external alignment beams nor modifications to the cavity are required. The rear mirror of the laser cavity is replaced by a tip/tilt mirror to compensate for the misalignment. Experiments show that this method could effectively correct the misalignment of the laser cavity and restore the output power to almost the original value when the resonator is well aligned. 相似文献
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