Fig. 2

(a) Recorded full-field hologram of an nRBC by microsphere-assisted DHM using a 234 μm diameter microsphere. The fiber lever connected to the microsphere can be seen in a panel with a dark grey appearance. (b) expanded view of the region of interest around the RBC enclosed by the dashed square depicted in panel (a), and (c) its associated reference hologram. (d) and (e) Fourier spectra of the object (b) and reference (c) holograms, respectively, which include three frequency regions associated with virtual and real images, as well as the zero-order term of Eq. (2). Either of the regions can be selected, shifted into the center of the domain, and subjected to proper numerical propagation to reach the complex amplitude of the image. (f) and (g) associated filtered frequency spectra after shifting and centering. To select the desired frequency component, a binary mask was applied, and then were then propagated to the best focus plane located at a distance z = d from the hologram plane according to Eq. (5). The phase map of the sample can be derived from the complex amplitude as discussed in Eq. (8), leading to the phase contrast image of the nRBC shown in panel (h). This image was obtained by subtracting the computed reference phase distribution from the object hologram to remove any image distortions. (i) Computed thickness distribution, and (j) its 2D view, using Eq. (9) after unwrapping the phase image depicted in (h). (k) Cross-sectional profile along the arbitrary line indicated in panel (j).