Elius Md, Ling Hangjian
Appl Opt. 2022 Nov 10;61(32):9415-9422. doi: 10.1364/AO.473763.
This paper discusses the effect of hologram plane position on the tracking of particle motions in a 3D suspension using digital holography microscopy. We compare two optical configurations where the hologram plane is located either just outside the particle suspension or in the middle of the suspension. In both cases, we record two axially separated holograms using two cameras and subsequently adopt an iterative phase retrieval approach to solve the virtual image problem. We measure the settling motions of 2 µm spheres in a 2 mm thick sample containing 300 to 1500 / . We show that the optical setup where the hologram plane is located in the middle of the sample provides superior tracking results compared to the other, including higher accuracy in the measurement of particle displacement and longer particle trajectories. The accuracy of particle displacement increases by a maximum of 18%, and the trajectory length increases by a maximum of 16%. This superior outcome is due to the less overlapping of the diffraction patterns on the holograms when the separation distance between particles and the hologram plane is minimized.
本文讨论了全息图平面位置对使用数字全息显微镜跟踪三维悬浮液中粒子运动的影响。我们比较了两种光学配置，其中全息图平面要么位于粒子悬浮液的外部，要么位于悬浮液的中间。在这两种情况下，我们使用两个相机记录两个轴向分离的全息图，随后采用迭代相位检索方法来解决虚拟图像问题。我们测量了在厚度为2毫米、含有300至1500个/的样品中2微米球体的沉降运动。我们表明，与另一种配置相比，全息图平面位于样品中间的光学设置提供了更好的跟踪结果，包括在粒子位移测量方面更高的精度和更长的粒子轨迹。粒子位移的精度最多提高了18%，轨迹长度最多增加了16%。这种优越的结果是由于当粒子与全息图平面之间的分离距离最小时，全息图上衍射图案的重叠较少。
