title: Field-portable lensfree tomographic microscope.
abstract: We present a field-portable lensfree tomographic microscope, which can achieve sectional imaging of a large volume (∼20 mm(3)) on a chip with an axial resolution of <7 μm. In this compact tomographic imaging platform (weighing only ∼110 grams), 24 light-emitting diodes (LEDs) that are each butt-coupled to a fibre-optic waveguide are controlled through a cost-effective micro-processor to sequentially illuminate the sample from different angles to record lensfree holograms of the sample that is placed on the top of a digital sensor array. In order to generate pixel super-resolved (SR) lensfree holograms and hence digitally improve the achievable lateral resolution, multiple sub-pixel shifted holograms are recorded at each illumination angle by electromagnetically actuating the fibre-optic waveguides using compact coils and magnets. These SR projection holograms obtained over an angular range of ±50° are rapidly reconstructed to yield projection images of the sample, which can then be back-projected to compute tomograms of the objects on the sensor-chip. The performance of this compact and light-weight lensfree tomographic microscope is validated by imaging micro-beads of different dimensions as well as a Hymenolepis nana egg, which is an infectious parasitic flatworm. Achieving a decent three-dimensional spatial resolution, this field-portable on-chip optical tomographic microscope might provide a useful toolset for telemedicine and high-throughput imaging applications in resource-poor settings.
authors.affiliation: UCLA Electrical Engineering Department, University of California, Los Angeles, CA 90095, USA.
authors.forename: Serhan O
authors.initials: SO
authors.lastname: Isikman
authors.forename: Waheb
authors.initials: W
authors.lastname: Bishara
authors.forename: Uzair
authors.initials: U
authors.lastname: Sikora
authors.forename: Oguzhan
authors.initials: O
authors.lastname: Yaglidere
authors.forename: John
authors.initials: J
authors.lastname: Yeah
authors.forename: Aydogan
authors.initials: A
authors.lastname: Ozcan
mesh_terms: D000818:Animals; D048189:Hymenolepis nana / Q000166:cytology; D007909:Lenses; D046210:Microfluidic Analytical Techniques; D008853:Microscopy / Q000295:instrumentation*; D010063:Ovum; D018511:Systems Integration; D014054:Tomography / Q000295:instrumentation*