Lipke Wojciech, Winnik Julianna, Trusiak Maciej
Opt Express. 2022 Jun 6;30(12):21241-21257. doi: 10.1364/OE.458167.
We present the numerical analysis of the effect of the temporarily partially coherent illumination on the phase measurement accuracy in digital holography microscopy (DHM) and optical diffraction tomography (ODT), as reconstruction algorithms tend to assume purely monochromatic conditions. In the regime of reduced temporal coherence, we simulate the hologram formation in two different optical setups, representing classical off-axis two-beam and grating common-path configurations. We consider two ODT variants: with sample rotation and angle-scanning of illumination. Besides the coherence degree of illumination, our simulation considers the influence of the sample normal dispersion, shape of the light spectrum, and optical parameters of the imaging setup. As reconstruction algorithms we employ Fourier hologram method and first-order Rytov approximation with direct inversion and nonnegativity constraints. Quantitative evaluation of the measurement results deviations introduced by the mentioned error sources is comprehensively analyzed, for the first time to the best of our knowledge. Obtained outcomes indicate low final DHM/ODT reconstruction errors for the grating-assisted common-path configuration. Nevertheless, dispersion and asymmetric spectrum introduce non-negligible overestimated refractive index values and noise, and should be thus carefully considered within experimental frameworks.
由于重建算法往往假定为纯单色条件，我们对数字全息显微镜（DHM）和光学衍射层析成像（ODT）中暂时部分相干照明对相位测量精度的影响进行了数值分析。在时间相干性降低的情况下，我们在两种不同的光学设置中模拟全息图的形成，分别代表经典离轴双光束和光栅共光路配置。我们考虑两种ODT变体：样品旋转和照明角度扫描。除了照明的相干度外，我们的模拟还考虑了样品正常色散、光谱形状以及成像设置的光学参数的影响。作为重建算法，我们采用傅里叶全息图方法以及带有直接反演和非负约束的一阶Rytov近似。据我们所知，首次全面分析了上述误差源所引入的测量结果偏差的定量评估。所得结果表明，对于光栅辅助共光路配置，最终的DHM/ODT重建误差较低。然而，色散和不对称光谱会引入不可忽略的高估折射率值和噪声，因此在实验框架内应仔细考虑。
