New website getting online, testing
Study of low-noise phase-shifting digital holographic microscopy using a long working distance objective
  • Abstract

    In order to improve the measurement accuracy, a kind of phase shifting digital holographic microscopy based on a long working distance microscopic objective is proposed. In the setup, an LED is adopted as the illumination light source, which can suppress coherent noise effectively and hence improve the measurement accuracy. A michelson quasi-common-path interferometer is constructed by adding a beam-splitter between the long working distance objective and the sample. The layout of the setup is simple and it can be easily adjusted, and thus the interference can be come into being conveniently especially when the sample is illuminated with a partial light source. The blind phase-shifting interferometry is adopted in the reconstruction procedure, and the two-step blind phase-shifting algorithm is used to reconstruct the phase map of the measured sample. In the experiments, the height maps of a reflective USAF 1951 resolution target are measured under LED illumination and He-Ne laser illumination, respectively. The measurement results show that both coincide with each other; the phase noise under LED illumination is, however, reduced by 70% when compared with that under laser illumination. In addition, in order to further verify the effectiveness of the device, the device is used to measure a micro-nano rectangular step engraved on the silicon substrate. The measurement results are in good agreement with the nominal values. This technique can be potentially used in the topographic measurement of micro-structures.

    Keywords

  • 采用LED作为照明光源的数字全息显微中,王海珊等[]以及Kemper课题组[]基于林尼克干涉仪,在物体及参考镜前分别放置显微物镜,实现对物体的放大,并应用相移算法重建了反射式微纳物体的表面结构。Dubois等[]基于马赫曾德干涉仪,在物光路与参考光路中分别放置相同的显微物镜以及辅助透镜组,实现了物光与参考光的干涉,对透射式微纳物体进行了三维重建。以上方案中所使用的林尼克干涉仪与马赫曾德干涉仪是典型的物参分离干涉结构,物参分离干涉结构由于光路中光学元件比较分散,容易受到外界环境振动的影响,物光臂与参考光臂中显微物镜和任意一个透镜的微小的横向或轴向偏移都有可能造成物光与参考光的光程差大于光源的相干长度,从而无法形成干涉条纹[-]。相比而言,物参共路干涉结构由于物光与参考光经过相同的路径[],可以有效地减小外界环境振动对光路的影响,使得物光与参考光光程相等,在数字全息显微中容易发生干涉。

    在数字全息显微中,通常采用激光作为照明光源。激光由于其相干长度长,易产生干涉条纹,因此被广泛使用。但是激光相干噪声较大,它在光学元件表面的多次反射会引起寄生干涉条纹,使得全息图的信噪比减小,成像质量降低[-]。为了减小相干噪声,提高成像质量,提出了许多不同的方法。目前常用方法分为两类,一类是在全息图的获取过程中,通过采用偏振、多角度照明等光学方法降低图像中的噪声,但是增加了光路结构的复杂性。另一类是采用图像处理方法对再现像降噪滤波,此方法对不同的噪声处理效果不同,普遍适应性不强[-]。除了这两类常用方法之外,降低相干噪声最直接的方法是将相干性强的激光光源改为相干性较弱的部分相干光,例如采用常见的LED作为照明光源[-],可有效地降低光源的时间及空间相干性,抑制相干噪声。

    为了解决以上问题,本文基于长工作距离物镜,提出了一种新的采用LED作为照明光源的相移数字全息显微装置。长工作距离物镜是一种工作距离较长的物镜,由于其工作距离长,它可以通过培养皿或厚的盖玻片等对生物细胞、流体等材料进行显微观察,常用于体外(in-vitro)生物组织细胞成像的研究[-]。本文利用长工作距离物镜的工作距离长的特点,通过在长工作距离物镜与样品之间放置一个分光棱镜的方法,构建了一个微型迈克尔逊干涉仪。在该装置中,物光和参考光经过几乎相同的路径,结构紧凑,调整方便。实验中,采用LED作为照明光源,减小了相干噪声,提高了重建精度。在此基础上,采用低成本的机械微位移平台代替昂贵的压电陶瓷移相器实现相移,应用两步轻离轴盲相移干涉技术,完成全息图的数值再现。

    数字全息显微是利用CCD或CMOS记录全息图并于计算机进行数值重建得到物体的振幅与相位信息的一种显微技术[-],数字全息显微是数字全息与光学显微的结合,具有非接触、无损伤、高分辨、可定量获得物体相位分布的优点[],因此广泛应用于生物样品成像[]、三维形貌检测[-]、流场测量[]等领域。

    实验装置如图 1所示,光源LED发出的光波经显微物镜会聚后被小孔1滤波,经过透镜1后变为平行光,再经非偏振分光棱镜分为两路,一路照明待测样品,另一路照明参考镜。从样品反射回去的光,经非偏振分光棱镜反射后,被长工作距离物镜放大,通过透镜2后变为平面光波;另一路从参考镜反射回去的光波作为参考光。为了改变参考光波的光程,实验中参考镜放置于机械微位移平台上,通过旋转螺旋测微尺可以改变参考光的光程。水平调节参考镜的位置,可以使物光波和参考光波的光程近似相等,从而使两者发生干涉得到全息图。通过轻微调节参考镜的法向方向,可以改变全息图中条纹的疏密及走向。为了记录全息图,CCD相机放置于透镜2的后方焦平面处。

    Figure 1. Experimental setup of phase-shifting interferometry based on a long working distance objectiv
    Full-Size Img PowerPoint

    Experimental setup of phase-shifting interferometry based on a long working distance objectiv

    由于LED光波的相干长度短,物光和参考光直接干涉不能得到密集的离轴干涉条纹,因此不能从一副干涉图中得到物光波的相位信息。为了解决这个问题,采用两步盲相移的重建方法[]。为了在两幅全息图之间引入相移,可以轻微地旋转螺旋测微尺,改变参考光的光程。装置中采用的是工作距离为33.5 mm的长工作距离物镜,样品、参考镜距离非偏振分光棱镜非常近,因此光路结构紧凑,构建了一种准物参共路的迈克尔逊干涉仪。由于用到的光学元件少,物光和参考光的光程容易调节实现相等。

    式中i为虚数符号。然后,通过反正切函数获得物光波的包裹相位分布φw(x, y):

    为了从记录的干涉条纹中得到被测相位分布φ(x, y),这里采用两步盲相移算法[],两步盲相移算法是对两幅未知相移量的相移干涉图进行处理,它是基于傅里叶变换的方法确定未知相移量进而重建相位的一种方法。

    δ2=Imln[i2(kx,ky)]ln[i1(kx,ky)],

    对反射式测量样品,其面型高度分布与相位分布有如下关系:

    由于采用的是轻离轴相移技术,物体的+1级谱、零级谱与共轭谱在频谱域重叠。零级谱通过图像相减的方法去除[],因此算法第一步是两幅全息图分别减去物光光强|O(x, y)|2以及参考光光强|R(x, y)|2,得到两幅去除直流分量的干涉图I1'和I2'。然后分别对I1'和I2'做傅里叶变换到频域,得到两幅频谱图i1'和i2'。由于轻离轴干涉图存在载频项,在频谱图中物光频谱和其共轭频谱必然存在相应的峰值,只要物光波的谱峰没有与共轭光波谱峰重叠,即可通过下式(2)得到相移量。通常假设第一次记录全息图时相移量δ1=0,则两幅全息图之间的相移量即第二次记录全息图时参考光引入的相移量δ2

    In(x,y)=|O(x,y)|2+|R(x,y)|2+2|O(x,y)||R(x,y)|cos[2π(kxx+kyy)+φ(x,y)+δn],
    O(x,y)=[I1exp(iδ2)I2]exp[i2π(kxx+kyy)][1exp(i2δ2)],

    式中:n=1, 2;(x, y)是记录平面的坐标,O(x, y)、R(x, y)分别表示物光波与参考光波,(kxky)分别为沿xy方向的空间载波频率,φ(xy)为需要测量的相位分布,即对物光波与参考光波之间的相对相位差,δn为第n次记录时物光与参考光之间引入的相移量。

    φw(x,y)=arctanIm[O(x,y)]Re[O(x,y)],

    图 1所示实验装置中,通过旋转机械微位移平台的螺旋测微尺沿轴向移动参考镜,在参考光中引入相移,记录两幅相移的轻离轴全息图。轻离轴全息图是在物光与参考光在干涉角接近零度的情况下记录的,降低了同轴干涉下物光与参考光之间角度严格为零的要求,同时,仍可在全视场内获得良好对比度的干涉条纹[]。干涉图的强度In(x, y)可以表示为

    h(x,y)=λφ(x,y)4π

    式中:Re表示对复数取实部。对包裹相位φw(x, y),利用相位解包裹算法,即可得到无包裹相位分布φ(x, y),即为物体的真实相位分布。

    通过该式,即可得到样品的高度分布。

    式中:ln为自然对数算符,Im表示对复数取虚部。求出相移量δ2后,物光波可通过两幅无直流项的干涉图重建:

    Figure 2. (a) Hologram 1; (b) Hologram 2; (c) Object intensity; (d) Reference intensity
    Full-Size Img PowerPoint

    (a) Hologram 1; (b) Hologram 2; (c) Object intensity; (d) Reference intensity

    为了验证实验装置和算法,对一个样品进行了测量。实验中样品为刻在硅基底上的USAF1951分辨率板;光源是LED,中心波长为630 nm,半高宽为21 nm,对应的相干长度为8.3 μm;长工作距离物镜的数值孔径为0.28,工作距离为33.5 mm;CCD相机的分辨率是1040像素×1388像素,像元大小是6.45 μm×6.45 μm。实验中首先调整样品位于长工作距离物镜的工作距离处,使样品清晰成像于CCD上。然后通过移动参考镜使得参考光与物光光程相等发生干涉,通过调节参考镜的俯仰,在物光与参考光之间引入轻微的离轴角α,获得空间频率较低的离轴像面全息图。为了实现相移,轻微旋转螺旋测微尺前后移动参考镜,通过改变光程的方法引入相移,如图 2(a)图 2(b)所示,分别为相移前和相移后的两幅全息图。根据两步盲相移算法,还需记录物光强度图以及参考光强度图,通过分别遮挡参考镜和样品的方法记录的物光强度图及参考光强度图,如图 2(c)图 2(d)所示。

    此外,为了展示LED光源具有的低相干噪声的特点,在相同的条件下,使用He-Ne激光器作为照明光源,对同一样品进行了测量,并对比了两种光源照明下测量结果的相位噪声。图 4(a)为激光照明下记录的一幅全息图,与LED光源所记录的全息图图 2(a)以及图 2(b)相比,图中的相干噪声显著增加。图 4(b)为重建的高度分布图,可见重建结果与LED光源照明时的高度分布图 3(b)相似,但是在无样品区域,图 4(b)中的噪声更大。为了直观地对比两种光源照明时的重建结果,给出了图 4(b)图 3(b)中相同位置处沿白色划线的截面图的分布如图 4(c)所示。从图 4(c)中可以看出,两种光源的测量结果相互吻合,激光照明时所测得的平均高度为205 nm,LED照明时测得的平均高度为202 nm。由于样品的标称值为200 nm,可见测量结果与标称值具有很好的一致性,但激光照明下的测量结果起伏较大。由此可见,对比两种光源下的测量结果,由于相位噪声的影响,激光的重建结果相比于LED的重建结果误差更大。

    为了定量地描述LED光源与激光光源照明时,重建结果中相位噪声的大小。在图 3(b)图 4(b)中选取相同的平坦的、无样品区域,如两幅图中白色矩形框所示,分别计算此区域噪声的标准偏差Std图 3(b)Std值为1.6 nm,图 4(b)中噪声的Std值为5.4 nm。结果表明,He-Ne激光器照明下重建结果的相位噪声为LED照明下相位噪声的3.4倍,说明LED照明下相位噪声较He-Ne激光器照明时降低了70%。由此可见,使用LED作为照明光源可有效抑制相位噪声,提高测量精度。

    Figure 3. (a) Wrapped phase map; (b) Height map
    Full-Size Img PowerPoint

    (a) Wrapped phase map; (b) Height map

    Figure 4. (a) A hologram with He-Ne laser illumination; (b) Height map with He-Ne laser illumination; (c) Height profiles along the white lines in Fig. 3(b) and Fig. 4(b)
    Full-Size Img PowerPoint

    (a) A hologram with He-Ne laser illumination; (b) Height map with He-Ne laser illumination; (c) Height profiles along the white lines in Fig. 3(b) and Fig. 4(b)

    在相位重建过程中,根据式(2),得到两幅全息图之间的相移量为0.877 rad;然后将所得到的相移量代入式(3),即可得到物光波的包裹相位分布,如图 3(a)所示。由于物光与参考光之间微小离轴角的存在,因此从图 3(a)中可以看出被测样品的相位图中存在线性包裹相位分布。利用解包裹算法,得到无包裹相位分布,即为最终的相位分布图,然后根据式(5)转换为高度分布图,如图 3(b)所示。

    另外,还比较了LED和He-Ne激光器这两种光源照明时的分辨率。由于系统的分辨本领主要由物镜的数值孔径决定,因此在相同物镜下,不同光源照明时分辨率应该一致。从图 3(b)图 4(b)中可见,两者分辨率几乎相同。为了直观清晰地对比分辨率的高低,分别放大显示了图 3(b)图 4(b)中白色虚线框部分。从放大图中可以看到,两种光源照明下的系统分辨率并无明显差异,但是激光照明时的相干噪声大,使得测量结果的起伏较大。

    为了进一步验证方案的有效性,采用该装置对刻在硅基底的微纳矩形台阶进行了测量。

    Figure 5. (a) A hologram; (b) Object height map; (c) Height profile along the black line in Fig. 5(b)
    Full-Size Img PowerPoint

    (a) A hologram; (b) Object height map; (c) Height profile along the black line in Fig. 5(b)

    图 5(a)为CCD记录的一幅全息图,图 5(b)为重建得到的物体高度分布图。为了更明确地观察物体的重建结果,我们给出了图 5(b)中的黑色实线部分的高度截面分布图,如图 5(c)所示。从图 5(c)中可以得到,沿黑色实线部分物体的平均高度为198 nm,与台阶的标称值200 nm具有很好的一致性。实验证明,该装置可以应用于微结构表面的三维形貌精密测量。

    提出了一种利用长工作距离物镜的相移数字全息显微的测量装置和方法,并通过实验验证了方案的可行性。实验中对在硅基底上制作的反射式USAF1951分辨率板以及矩形台阶进行了测量,测量结果与标称值具有很好的一致性。此外,分别在LED照明与激光照明时对物体的三维面型分布进行了测量。对比测量结果可知,LED光源照明的相位噪声与激光照明时相比降低了70%,因此,LED光源可以有效降低相位噪声。与其他数字全息显微装置相比,该装置不仅采用低成本的LED光源,而且利用微位移平台移动参考镜引入相移,抛弃了成本高昂的压电陶瓷移相器,实现了对微纳物体的低成本的测量。结合两步盲相移算法,使得数值重建过程简单快捷。另一方面,通过在长工作距离物镜和样品之间加入分光棱镜的方法,构建了一种紧凑的准物参共路的迈克尔逊干涉仪,光路结构简单,调整方便,在短相干长度的光波照明时,容易实现干涉。基于这些优点,该测量方案可方便地用于对微结构表面形貌的低噪声测量。

  • References

    Zhang Y Y, Zhao J L, Di J L, et al. Real-time monitoring of the solution concentration variation during the crystallization process of protein-lysozyme by using digital holographic interferometry[J]. Optics Express, 2012, 20(16):18415-18421.

    DOI: 10.1364/OE.20.018415

    CrossRef Google Scholar

    Min J W, Yao B L, Ketelhut S, et al. Simple and fast spectral domain algorithm for quantitative phase imaging of living cells with digital holographic microscopy[J]. Optics Letters, 2017, 42(2):227-230.

    DOI: 10.1364/OL.42.000227

    CrossRef Google Scholar

    周战荣.单次相移数字全息中相移值的提取[J].光电工程, 2009, 36(7):117-120.

    DOI: 10.3969/j.issn.1003-501X.2009.07.022

    Zhou Z R. Phase-shifting value extraction on digital holography with single phase-shifting operation[J]. Opto-Electronic Engineering, 2009, 36(7):117-120.

    DOI: 10.3969/j.issn.1003-501X.2009.07.022

    CrossRef Google Scholar

    Zheng J J, Zuo C, Gao P, et al. Dual-mode phase and fluorescence imaging with a confocal laser scanning microscope[J]. Optics Letters, 2018, 43(22):5689-5692.

    DOI: 10.1364/OL.43.005689

    CrossRef Google Scholar

    Yue Q Y, Cheng Z J, Han L, et al. One-shot time-resolved holographic polarization microscopy for imaging laser-induced ultrafast phenomena[J]. Optics Express, 2017, 25(13):14182-14191.

    DOI: 10.1364/OE.25.014182

    CrossRef Google Scholar

    Xue L, Wang S Y, Yan K D, et al. Fast pixel shifting phase unwrapping algorithm in quantitative interferometric microscopy[J]. Chinese Optics Letters, 2014, 12(7):071801.

    DOI: 10.3788/COL201412.071801

    CrossRef Google Scholar

    View full references list
  • Cited by

    Periodical cited type(2)

    1. 林阿愿,王瑾瑜,陈宇昕,齐沛良,黄志云,谭小地. 同偏振记录偏光全息的零再现. 光电工程. 2022(05): 75-82 . 本站查看
    2. 王阳,张美玲,王宇,温凯,卓可群,郭荣礼,郜鹏. 部分相干光照明的数字全息显微技术及应用. 激光与光电子学进展. 2021(18): 150-165 .

    Other cited types(5)

  • Author Information

  • Copyright

    The copyright belongs to the Institute of Optics and Electronics, Chinese Academy of Sciences, but the article content can be freely downloaded from this website and used for free in academic and research work.
  • About this Article

    DOI: 10.12086/oee.2019.190140
    Cite this Article
    Hui Qiannan, Duan Cunli, Feng Bin, Wang Fan, Guo Rongli. Study of low-noise phase-shifting digital holographic microscopy using a long working distance objective. Opto-Electronic Engineering 46, 190140 (2019). DOI: 10.12086/oee.2019.190140
    Download Citation
    Article History
    • Received Date March 26, 2019
    • Revised Date July 23, 2019
    • Published Date November 30, 2019
    Article Metrics
    Article Views(9778) PDF Downloads(2574)
    Share:
  • Related Articles

Zhang Y Y, Zhao J L, Di J L, et al. Real-time monitoring of the solution concentration variation during the crystallization process of protein-lysozyme by using digital holographic interferometry[J]. Optics Express, 2012, 20(16):18415-18421.

DOI: 10.1364/OE.20.018415

CrossRef Google Scholar

Min J W, Yao B L, Ketelhut S, et al. Simple and fast spectral domain algorithm for quantitative phase imaging of living cells with digital holographic microscopy[J]. Optics Letters, 2017, 42(2):227-230.

DOI: 10.1364/OL.42.000227

CrossRef Google Scholar

周战荣.单次相移数字全息中相移值的提取[J].光电工程, 2009, 36(7):117-120.

DOI: 10.3969/j.issn.1003-501X.2009.07.022

Zhou Z R. Phase-shifting value extraction on digital holography with single phase-shifting operation[J]. Opto-Electronic Engineering, 2009, 36(7):117-120.

DOI: 10.3969/j.issn.1003-501X.2009.07.022

CrossRef Google Scholar

Zheng J J, Zuo C, Gao P, et al. Dual-mode phase and fluorescence imaging with a confocal laser scanning microscope[J]. Optics Letters, 2018, 43(22):5689-5692.

DOI: 10.1364/OL.43.005689

CrossRef Google Scholar

Yue Q Y, Cheng Z J, Han L, et al. One-shot time-resolved holographic polarization microscopy for imaging laser-induced ultrafast phenomena[J]. Optics Express, 2017, 25(13):14182-14191.

DOI: 10.1364/OE.25.014182

CrossRef Google Scholar

Xue L, Wang S Y, Yan K D, et al. Fast pixel shifting phase unwrapping algorithm in quantitative interferometric microscopy[J]. Chinese Optics Letters, 2014, 12(7):071801.

DOI: 10.3788/COL201412.071801

CrossRef Google Scholar

范锋, 栗军香, 宋修法, 等.基于Hilbert变换实现数字全息高精度相位重建[J].物理学报, 2014, 63(19):194207.

DOI: 10.7498/aps.63.194207

Fan F, Li J X, Song X F, et al. High accuracy phase reconstruction of digital hologram by Hilbert transform[J]. Acta Physica Sinica, 2014, 63(19):194207.

DOI: 10.7498/aps.63.194207

CrossRef Google Scholar

田鹏, 严伟, 李凡星, 等.均匀球面波数字同轴全息生物显微方法[J].光电工程, 2019, 46(1):180110.

http://www.oejournal.org/J/OEE/Article/Details/A181222000004/CN

Tian P, Yan W, Li F X, et al. Biology microscopy using well-distributed sphere digital in-line holography[J]. Opto-Electronic Engineering, 2019, 46(1):180110.

http://www.oejournal.org/J/OEE/Article/Details/A181222000004/CN

Google Scholar

王云新, 王大勇, 赵洁, 等.基于数字全息显微成像的微光学元件三维面形检测[J].光学学报, 2011, 31(4):0412003.

http://d.old.wanfangdata.com.cn/Conference/7492216

Wang Y X, Wang D Y, Zhao J, et al. 3D profile measurement for micro-optical component by using digital holographic microscopy[J]. Acta Optica Sinica, 2011, 31(4):0412003.

http://d.old.wanfangdata.com.cn/Conference/7492216

Google Scholar

张倩, 徐先锋, 袁红光, 等.四步相移数字全息干涉术相移提取和物光重建[J].光电工程, 2011, 38(8):139-144.

DOI: 10.3969/j.issn.1003-501X.2011.08.023

Zhang Q, Xu X F, Yuan H G, et al. Phase-shift extraction and wave reconstruction in four-step phase-shifting interferometry[J]. Opto-Electronic Engineering, 2011, 38(8):139-144.

DOI: 10.3969/j.issn.1003-501X.2011.08.023

CrossRef Google Scholar

王凤鹏, 邓世桂, 张选洲, 等.同轴数字全息视频动态跟踪处理实验[J].光电工程, 2014, 41(6):81-86.

DOI: 10.3969/j.issn.1003-501X.2014.06.014

Wang F P, Deng S G, Zhang X Z, et al. Processing experiments of digital in-line holographic video[J]. Opto-Electronic Engineering, 2014, 41(6):81-86.

DOI: 10.3969/j.issn.1003-501X.2014.06.014

CrossRef Google Scholar

邓慧, 张蓉竹, 孙年春.激光光束非相干叠加对散斑噪声抑制情况[J].光学学报, 2016, 36(1):0129002.

http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=gxxb201601035

Deng H, Zhang R Z, Sun N C. Suppression situation of incoherent superposition of laser beams on speckle noise[J]. Acta Optica Sinica, 2016, 36(1):0129002.

http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=gxxb201601035

Google Scholar

肖文, 王庆伍, 潘锋.小波结合双边滤波抑制全息相干噪声[J].光电工程, 2016, 43(8):39-46.

DOI: 10.3969/j.issn.1003-501X.2016.08.007

Xiao W, Wang Q W, Pan F. Suppression of coherent noise by wavelet combined with bilateral filtering in digital holography[J]. Opto-Electronic Engineering, 2016, 43(8):39-46.

DOI: 10.3969/j.issn.1003-501X.2016.08.007

CrossRef Google Scholar

Rong L, Xiao W, Pan F, et al. Speckle noise reduction in digital holography by use of multiple polarization holograms[J]. Chinese Optics Letters, 2010, 8(7):653-655.

DOI: 10.3788/COL20100807.0653

CrossRef Google Scholar

王大勇, 王云新, 郭莎, 等.基于多角度无透镜傅里叶变换数字全息的散斑噪声抑制成像研究[J].物理学报, 2014, 63(15):154205.

DOI: 10.7498/aps.63.154205

Wang D Y, Wang Y X, Guo S, et al. Research on speckle denoising by lensless Fourier transform holographic imaging with angular diversity[J]. Acta Physica Sinica, 2014, 63(15):154205.

DOI: 10.7498/aps.63.154205

CrossRef Google Scholar

Aum J H, Kim J H, Jeong J. Effective speckle noise suppression in optical coherence tomography images using nonlocal means denoising filter with double Gaussian anisotropic kernels[J]. Applied Optics, 2015, 54(13):D43-D50.

DOI: 10.1364/AO.54.000D43

CrossRef Google Scholar

Uzan A, Rivenson Y, Stern A. Speckle denoising in digital holography by nonlocal means filtering[J]. Applied Optics, 2013, 52(1):A195-A200.

DOI: 10.1364/AO.52.00A195

CrossRef Google Scholar

秦怡, 钟金钢.基于发光二极管的弱相干光数字全息理论与实验研究[J].光学学报, 2010, 30(8):2236-2241.

http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=gxxb201008012

Qin Y, Zhong J G. Theoretical and experimental research of digital holography with partially coherent light based on light-emitting diode[J]. Acta Optica Sinica, 2010, 30(8):2236-2241.

http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=gxxb201008012

Google Scholar

Monemhaghdoust Z, Montfort F, Emery Y, et al. Dual wavelength full field imaging in low coherence digital holographic microscopy[J]. Optics Express, 2011, 19(24):24005-24022.

DOI: 10.1364/OE.19.024005

CrossRef Google Scholar

巩琼, 秦怡. LED光源数字全息技术研究[J].应用光学, 2010, 31(2):237-241.

DOI: 10.3969/j.issn.1002-2082.2010.02.016

Gong Q, Qin Y. LED-based digital holography[J]. Journal of Applied Optics, 2010, 31(2):237-241.

DOI: 10.3969/j.issn.1002-2082.2010.02.016

CrossRef Google Scholar

王海珊, 史铁林, 廖广兰, 等.基于干涉显微原理的表面形貌测量系统[J].光电工程, 2008, 35(7):84-89.

DOI: 10.3969/j.issn.1003-501X.2008.07.017

Wang H S, Shi T L, Liao G L, et al. Profilometer based on interferometry and micro vision system[J]. Opto-Electronic Engineering, 2008, 35(7):84-89.

DOI: 10.3969/j.issn.1003-501X.2008.07.017

CrossRef Google Scholar

Kemper B, Sturwald S, Remmersmann C, et al. Characterisation of light emitting diodes (LEDs) for application in digital holographic microscopy for inspection of micro and nanostructured surfaces[J]. Optics and Lasers in Engineering, 2008, 46(7):499-507.

DOI: 10.1016/j.optlaseng.2008.03.007

CrossRef Google Scholar

Dubois F, Yourassowsky C. Full off-axis red-green-blue digital holographic microscope with LED illumination[J]. Optics Letters, 2012, 37(12):2190-2192.

DOI: 10.1364/OL.37.002190

CrossRef Google Scholar

李勇, 吴奎, 卢荣胜, 等. Linnik白光干涉仪自动对焦及光程差最小化[J].光电工程, 2012, 39(11):8-16.

DOI: 10.3969/j.issn.1003-501X.2012.11.002

Li Y, Wu K, Lu R S, et al. Automated method of focusing and minimizing OPD in Linnik white light interferometry[J]. Opto-Electronic Engineering, 2012, 39(11):8-16.

DOI: 10.3969/j.issn.1003-501X.2012.11.002

CrossRef Google Scholar

Guo R L, Yao B L, Gao P, et al. Off-axis digital holographic microscopy with LED illumination based on polarization filtering[J]. Applied Optics, 2013, 52(34):8233-8238.

DOI: 10.1364/AO.52.008233

CrossRef Google Scholar

Zhao J L, Di J L, Zhang J W, et al. Common-path digital holographic microscopy and its applications[J]. Proceedings of SPIE, 2016, 10022:1002202.

Google Scholar

Di J L, Wang K Q, Zhang J W, et al. Quasicommon-path digital holographic microscopy with phase aberration compensation based on a long-working distance objective[J]. Optical Engineering, 2018, 57(2):024108.

http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=c5c4b70b69fba695f460a9ee20b10cb3

Google Scholar

Guo R L, Wang F. Compact and stable real-time dual-wavelength digital holographic microscopy with a long-working distance objective[J]. Optics Express, 2017, 25(20):24512-24520.

DOI: 10.1364/OE.25.024512

CrossRef Google Scholar

Sinclair M B, de Boer M P, Corwin A D. Long-working-distance incoherent-light interference microscope[J]. Applied Optics, 2005, 44(36):7714-7721.

DOI: 10.1364/AO.44.007714

CrossRef Google Scholar

Guo R L, Yao B L, Min J W, et al. LED-based digital holographic microscopy with slightly off-axis interferometry[J]. Journal of Optics, 2014, 16(12):125408.

DOI: 10.1088/2040-8978/16/12/125408

CrossRef Google Scholar

Related Articles
Show full outline

Catalog

    Corresponding author: Guo Rongli, guorongli@xatu.edu.cn

    1. On this Site
    2. On Google Scholar
    3. On PubMed
    Study of low-noise phase-shifting digital holographic microscopy using a long working distance objective
    • Figure  1
    • Figure  2
    • Figure  3
    • Figure  4
    • Figure  5