Portable single-shot lens-free tomographic microscope for imaging dynamic specimens.

We present a portable single-shot lens-free tomographic microscope, based on spatial multiplexing in-line digital holography, for three-dimensional (3D) imaging of dynamic specimens. The simplified system is realized by only a laser diodes array, a rectangular aperture, and a CMOS image sensor with a global shutter, which enables the recording of all the complex fields of a dynamic specimen from different illumination angles without any scanning mechanism by a multiplexing hologram, in a single camera exposure. Using our proposed data processing method, high-quality 3D tomograms, with a lateral resolution of 3.36μm and an axial resolution of 6.39μm within an imaging field-of-view of 5.06 mm, can be eventually reconstructed from a multiplexing hologram. Experimental results of free-swimming paramecium in water demonstrates the systems potential in 3D imaging living or rapidly moving specimens in resource-limited environments.