Compact and Cost-effective Lensless Tomographic On-chip Microscope

We present a field-portable lens-free optical tomographic microscope, which enables sectional-imaging of a large sample volume (~20 mm) with an axial-resolution of <7 μm. This platform, weighing ~110 grams, employs cost-effective lightemitting diodes and an optoelectronic sensor array to record in-line projection holograms of objects placed on a sensor-chip along different directions of illumination. Using pixel super-resolution techniques and digital holographic reconstruction followed by a filtered back-projection algorithm, three-dimensional images of objects are computed over a large imaging volume. The imaging performance is demonstrated using micro-beads of different dimensions as well as a Hymenolepis Nana egg, which is an infectious parasitic flatworm.