Volumetric reconstruction
of a complex 3D object via refocusing:
Teflon and sugar particles on plastic slabs. (a) Optical image of
the sample. (b) Conceptual illustration of the sample’s composition.
(c) Temporal response of the sample. (d) Fixed-time reconstructed
images at the peak time. (e) Conceptual sketch of the imaging scheme:
refocusing planes highlighted. (f, g) Spectral and phase images at
0.5 THz at the initial focal plane z = 0 μm.
(h, i) Spectral and phase images at 0.5 THz averaged between z = 310 μm and z = 370 μm,
showing Teflon’s contribution. (j, k) Spectral and phase images
at 0.5 THz averaged between z = 510 μm and z = 570 μm, highlighting the sugar’s contribution.
In all panels, the field of view is 4 mm × 4 mm with a 32 ×
32 spatial sampling. The white bar represents the 500 μm scale.
Supplementary videos are reported for the raw data (Videos S3 and S4).