Promotionsvortrag Physik: Different approaches performing cross-polarised optical coherence Tomography – New ways revealing tissue’s birefringence properties endoscopically

Ankündigung des Promotionsvortrags von: Frau Katharina Blessing

Driven by the idea of enabling non-invasive optical biopsies, optical coherence tomography (OCT) was successfully implemented in endoscopic systems. Cross-polarised (cp)OCT offers a compel-ling extension to conventional OCT, adding the birefringence properties as additional contrast to the data. It suits to delineate different types of tissue. In this thesis, we present and compare four approaches to realise cpOCT which are compatible with commercially available swept-source en-gines independent of the source's polarization state. Datasets are acquired simultaneously, yield-ing depth-encoded images. Inspired by a benchtop approach, we develop two endoscopic com-mon-path systems. Both systems operate fully independently of illumination's polarisation. In addi-tion to these imaging modules which generate orthogonal polarisation states in free-space, we present a full-fibre approach. A novel monolithic mirror-based probe design enables the endoscop-ic integration. This design resolves the typical trade-off between resolution enhancement and sen-sitivity which is encountered in this type of probes. The corresponding publication presents a proof-of-principle. For in-vivo use, we suggest a manufacturing protocol for a side-viewing variant.

In conclusion, we present and compare four innovative and surprisingly simple cpOCT approaches compatible with swept-source engines. Targeting miniaturised endoscopic systems, we present a flexible common-path probe (CPP) design. Combined with the independence from the illumina-tion's polarisation state, the endoscopic systems enable robust and shock-insensitive data acquisi-tion.

(Vortrag auf Englisch)

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