Suppression of the non-linear background in a multimode fibre CARS endoscope

0553554 - ÚPT 2023 RIV US eng J - Journal Article
Pikálek, Tomáš - Stibůrek, Miroslav - Simpson, Stephen Hugh - Čižmár, Tomáš - Traegaardh, Johanna
Suppression of the non-linear background in a multimode fibre CARS endoscope.
Biomedical Optics Express. Roč. 13, č. 2 (2022), s. 862-874, č. článku 450375. ISSN 2156-7085
R&D Projects: GA MŠMT EF15_003/0000476; GA MŠMT(CZ) EF16_013/0001775; GA MŠMT(CZ) EF18_046/0016045
Research Infrastructure: Czech-BioImaging II - 90129
Institutional support: RVO:68081731
Keywords : resolution * microscopy * probe * myelin * light
OECD category: Optics (including laser optics and quantum optics)
Impact factor: 3.4, year: 2022
Method of publishing: Open access
https://opg.optica.org/boe/fulltext.cfm?uri=boe-13-2-862&id=468619

Multimode fibres show great potential for use as miniature endoscopes for imaging deep in tissue with minimal damage. When used for coherent anti-Stokes Raman scattering (CARS) microscopy with femtosecond excitation sources, a high band-width probe is required to efficiently focus the broadband laser pulses at the sample plane. Although graded-index (GRIN) fibres have a large bandwidth, it is accompanied by a strong background signal from four-wave mixing and other non-linear processes occurring inside the fibre. We demonstrate that using a composite probe consisting of a GRIN fibre with a spliced on step-index fibre reduces the intensity of the non-linear background by more than one order of magnitude without significantly decreasing the focusing performance of the probe. Using this composite probe we acquire CARS images of biologically relevant tissue such as myelinated axons in the brain with good contrast.
Permanent Link: https://hdl.handle.net/11104/0333682