Fig. 1. The expansion of the imaging SBP. (a) Schematic diagram of the expansion in spatial domain to expand the spatial imaging range; (b) the multi-scale optical imaging system based on the camera array^[36-37]; (c) the large field of view biological microscopic system based on the camera array^[38]; (d) schematic diagram of frequency domain expansion, expanding the frequency passband range of existing optical systems; (e) fourier ptychographic microscopy system based on multi-angle illumination^[40]; (f) lensless on-chip imaging systems based on multi-angle illumination^[41]

Fig. 2. Schematic diagram of conventional off-axis digital holography. FT indicates the Fourier transform

Fig. 3. Schematic diagram of digital holographic multiplexing and its applications. (a) Schematic diagram of dual-channel off-axis holographic multiplexing; (b) expanding imaging field of view based on digital holographic multiplexing^[47]; (c) expanding imaging resolution based on digital holographic multiplexing^[49]; (d) expanding imaging depth of field based on digital holographic multiplexing^[50]

Fig. 4. Numerical calculation results. (a) Digital holographic multiplexing model, taking two channels as an example; (b)～(c) phase distribution of original object; (d) fourier spectrum of the 2-channel multiplexed hologram, and the spectra are completely separated from other terms; (e)～(f) the reconstructed phases from (d); (g) fourier spectrum of the 2-channel multiplexed hologram, the object spectra are overlapped with other terms; (h)～(i) the reconstructed phases from (g); (j) fourier spectrum of 8-channel multiplexed hologram, 4 channels are the object 1, the other 4 channels are the object 2, and the object spectra are overlapped with other terms; (k)～(l) two of the reconstructed phases from (j)

Fig. 5. Numerical calculation results. (a) The MSE result of phase reconstruction as a function of acquisition bit depth; (b) the MSE result of phase reconstruction as a function of the amplitude value of reference wave

Fig. 6. Schematic diagram of the optical path of a digital holographic microscope with high spatial bandwidth utilization. (a) Extended field-of-view digital holographic microscope; (b) schematic diagram of optical multiplexing setup; (c) schematic diagram of field-of-view multiplexing^[48]

Fig. 7. Reconstruction images from digital holographic microscope with high spatial bandwidth utilization^[48]. (a) Multiplexed hologram; (b) spectrum of the multiplexed hologram; (c) high-throughput quantitative phase reconstruction from (a); (d) the hologram image obtained by conventional off-axis digital holographic microscope; (e) spectrum of conventional off-axis hologram; (f) the reconstruction results of conventional off-axis hologram in (d)