Whole phase curvature-based particle positioning and size determination by digital holography

2020 ◽  
Vol 59 (24) ◽  
pp. 7201
Author(s):  
Shin-ya Hasegawa ◽  
Takao Miaki
2020 ◽  
Author(s):  
George Nehmetallah ◽  
Logan Williams ◽  
Thanh Nguyen

In this Chapter, we discuss the latest advances in digital holography (DH) and digital holographic microscopy (DHM). Specifically, we study the different setup configurations such as single and multiwavelength approaches in reflection and transmission modes and the reconstruction algorithms used. We also propose two novel telecentric recording configurations for single and multi-wavelength digital holographic microscopy (TMW-DHM) systems. Brief theory and results are shown for each of the experimental setups discussed. The advantages and disadvantages of the different configurations will be studied in details. Typical configuration features are, ease of phase reconstruction, speed, vertical measurement range without phase ambiguity, difficulty in applying optical and numerical post-processing aberration compensation methods. Aberrations can be due to: (a) misalignment, (b) multiwavelength method resulting in Chromatic aberrations, (c) the MO resulting in parabolic phase curvature, (d) the angle of the reference beam resulting in linear phase distortions, and (e) different optical components used in the setup, such as spherical aberration, astigmatism, coma, and distortion. We conclude that telecentric configuration eliminates the need of extensive digital automatic aberration compensation or the need for a second hologram’s phase to be used to obtain the object phase map through subtraction. We also conclude that without a telecentric setup and even with post-processing a residual phase remains to perturb the measurement. Finally, a custom developed user-friendly graphical user interface (GUI) software is employed to automate the reconstruction processes for all configurations.


Author(s):  
Ye Yang ◽  
Suiyang Liao ◽  
Zhi Luo ◽  
Runzhang Qi ◽  
Niamh Mac Fhionnlaoich ◽  
...  

Accurate nanoparticle (NP) size determination is essential across research domains, with many functions in nanoscience and biomedical research being size-dependent. Although transmission electron microscopy (TEM) is capable of resolving a single NP down to the sub-nm scale, the reliable representation of entire populations is plagued by challenges in providing statistical significance, predominantly due to limited sample counts, suboptimal preparation procedures and operator bias during image acquisition and analysis. Meanwhile alternative techniques exist, but reliable implementation requires a detailed understanding of appendant limitations. Herein, conventional TEM is compared to the size determination of sub-10 nm gold NPs in solution by small-angle X-ray scattering and analytical ultracentrifugation. Form-free Monte Carlo fitting of scattering profiles offers access to a direct representation of the core size distribution while ultracentrifugation sedimentation velocity analysis provides information of the hydrodynamic size distribution. We report a comparison of these three methods in determining the size of quasi-monodisperse, polydisperse and bimodal gold nanoparticles of 2 – 7 nm and discuss advantages and limitations of each technique.


2020 ◽  
Vol 59 (SO) ◽  
pp. SOOE03
Author(s):  
Hiroyuki Ishigaki ◽  
Takahiro Mamiya ◽  
Yoshio Hayasaki

Author(s):  
Jae-Eun Pi ◽  
Ji-Hun Choi ◽  
Jong-Heon Yang ◽  
Chi-Young Hwang ◽  
Gi Heon Kim ◽  
...  

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