26th Australian Institute of Physics Congress and the Australian and New Zealand Conference on Optics and Photonics

Miniaturised 3D-printed Dual-fibre Optical Coherence Tomography Probe

Not scheduled

20m

Belinda Hutchinson Building (The University of Sydney )

Contributed Oral ANZOS | Photonics and Optics (ANZCOP)

Description

Optical coherence tomography (OCT) has been widely utilised for biomedical imaging since its early clinical use for retinal microstructural imaging[1]. It has subsequently become a versatile to a broad range of applications, such as cardiology and oncology[2]. This widespread adoption is largely due to OCT’s ability to provide non-invasive, depth-resolved images of tissue structures. However, a major challenge for OCT beyond ophthalmology is its shallow imaging depth in turbid tissue, typically limited to approximately 1-2 mm due to non-ballistic scattering. Multiple scattered photons are not usefully collected at greater depths the detectability of signals in deep tissue[3].
To address this limitation, free-space optical approaches such as Dual-axis OCT and Spatial Offset - OCT have been explored using spatially separated illumination and collection paths[3,4]. These geometric configurations allow for the preferential detection of multiple scattered photons thereby to improve contrast in deeper tissue regions. However, the large size and alignment sensitivity of free-space systems make them difficult to integrate into compact fibre-based systems. This represents a significant barrier for intravascular and endoscopic imaging. In this study, we adapt and implement the off-axis illumination–collection concept into a fibre-based probe. This could provide a compact and mechanically stable approach for depth-enhanced OCT imaging, more suitable for clinical translation. The proposed probe implements a two-fibre architecture using a miniaturised 3D-printed lens integrated on the fibre facets, building on earlier work with single-fibre 3D-printed probes[5,6]. As shown in Figure 1, we have fabricated several fibre-based probes with this design, characterised their performance, and performed proof_of_principal imaging experiments to demonstrate the feasibility of the approach.
Acknowledgement: Benjamin Isaac Melville, Andrea Toulouse, and Bozhe Li. Funded by NHMRC grants (2022337 and 2008462), Australia-Germany Joint Research Co-operation Scheme (UA-DAAD) and the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation, Project number 418911744).