Observing distant objects with a multimode fiber-based holographic endoscope

0543628 - ÚPT 2022 RIV US eng J - Journal Article
Leite, I. T. - Turtaev, S. - Boonzajer Flaes, D. E. - Čižmár, Tomáš
Observing distant objects with a multimode fiber-based holographic endoscope.
APL Photonics. Roč. 6, č. 3 (2021), č. článku 036112. ISSN 2378-0967. E-ISSN 2378-0967
R&D Projects: GA MŠMT EF15_003/0000476
Institutional support: RVO:68081731
Keywords : multimode optical fibre * wavefront shaping * holography * transmission matrix
OECD category: Optics (including laser optics and quantum optics)
Impact factor: 6.382, year: 2021
Method of publishing: Open access
https://aip.scitation.org/doi/10.1063/5.0038367

Holographic wavefront manipulation enables converting hair-thin multimode optical fibers into minimally invasive lensless imaging instruments conveying much higher information densities than conventional endoscopes. Their most prominent applications focus on accessing delicate environments, including deep brain compartments, and recording micrometer-scale resolution images of structures in close proximity to the distal end of the instrument. Here, we introduce an alternative far-field endoscope capable of imaging macroscopic objects across a large depth of field. The endoscope shaft with dimensions of 0.2 x 0.4 mm(2) consists of two parallel optical fibers: one for illumination and the other for signal collection. The system is optimized for speed, power efficiency, and signal quality, taking into account specific features of light transport through step-index multimode fibers. The characteristics of imaging quality are studied at distances between 20 mm and 400 mm. As a proof-of-concept, we provide imaging inside the cavities of a sweet pepper commonly used as a phantom for biomedically relevant conditions. Furthermore, we test the performance on a functioning mechanical clock, thus verifying its applicability in dynamically changing environments. With the performance reaching the standard definition of video endoscopes, this work paves the way toward the exploitation of minimally invasive holographic micro-endoscopes in clinical and diagnostics applications.
Permanent Link: http://hdl.handle.net/11104/0320818