Su Ping, Sun Da, Ma Jianshe, Luo Zhenpeng, Zhang Hua, Feng Shilun, Cao Liangcai
Opt Express. 2021 Jan 18;29(2):1275-1288. doi: 10.1364/OE.411142.
Digital holographic microscopy with compressive sensing (CDHM) has successfully achieved tomography and has been applied in many fields. However, the enhancement of axial resolution in CDHM remains to be elucidated. By deducing accurate formulas for the lateral and axial resolutions without paraxial approximation, we quantized the elongation effect of a digital holography (DH) system in this study. Thus, we revealed that the elongation effect, which is affected only by the system's numerical aperture (NA), is an inherent property of DH systems. We present a detailed analysis herein on the physical significance of the coherence parameter, which is the ratio of a system's limit axial resolution to the interlayer spacing more thoroughly than in previous research. Further, we achieved the tomography of a fiber by using a DH system with a 10 × microscope, with CS to eliminate the elongation effect, and experimentally validated our theoretical results. By applying these theoretical guidelines, we distinguished crossed fibers at distances of 36.4 μm and 48.5 μm, respectively, using the same experimental setup. There would be potential applications of this theory in tomography and observation of microscale objects in the areas of biological and fluid.
具有压缩感知的数字全息显微镜（CDHM）已成功实现层析成像，并已应用于许多领域。然而，CDHM中轴向分辨率的提高仍有待阐明。通过推导无傍轴近似的横向和轴向分辨率的精确公式，我们在本研究中量化了数字全息（DH）系统的伸长效应。因此，我们揭示了仅受系统数值孔径（NA）影响的伸长效应是DH系统的固有属性。我们在此对相干参数的物理意义进行了详细分析，相干参数是系统极限轴向分辨率与层间距的比值，比以往研究更深入。此外，我们使用配备10×显微镜的DH系统，通过压缩感知（CS）消除伸长效应，实现了光纤的层析成像，并通过实验验证了我们的理论结果。通过应用这些理论指导方针，我们在相同的实验装置下，分别分辨出了距离为36.4 μm和48.5 μm的交叉纤维。该理论在生物和流体领域的层析成像以及微观物体观测方面具有潜在应用。
