Feng Pan, Wen Xiao, Lu Rong
School of Instrument Science and Opto-Electronics Engineering, Beijing University of Aeronautics and Astronautics, Beijing, China.
Opt Express. 2009 Mar 30;17(7):5473-80. doi: 10.1364/oe.17.005473.
An aperture synthesis approach of digital holography for microscopy imaging at long working distance is proposed. Firstly, for an oblique object, a series of Fresnel off-axis holograms are recorded with different tilted plane wave illuminations without using lens for pre-magnification. Then the complex amplitudes are reconstructed and magnified from these holograms by the double-step Fresnel reconstruction method respectively. Finally, the synthesized image of the resolution enhanced and the speckle suppressed is obtained by incoherent superposition of these reconstructed complex amplitudes. The important advantage of the proposed approach is that the working distance of the system isn't constrained and the reconstructed image doesn't subject to lens aberrations. The experimental results with a die and an USAF-1951 resolution test target are shown and demonstrated that the resolution of both intensity and phase image can be effectively enhanced with simple set-up and procedure. The proposed approach can improve the capabilities of digital holography in three-dimensional in-situ microscopy at long working distance.
提出了一种用于长工作距离显微镜成像的数字全息孔径合成方法。首先，对于倾斜物体，在不使用透镜进行预放大的情况下，用不同倾斜平面波照明记录一系列菲涅耳离轴全息图。然后分别通过双步菲涅耳重建方法从这些全息图中重建并放大复振幅。最后，通过这些重建复振幅的非相干叠加获得分辨率增强且散斑抑制的合成图像。该方法的重要优点是系统的工作距离不受限制，并且重建图像不受透镜像差的影响。展示了使用芯片和美国空军1951分辨率测试靶标的实验结果，证明了通过简单的设置和过程可以有效提高强度和相位图像的分辨率。所提出的方法可以提高数字全息在长工作距离三维原位显微镜中的能力。
