CARDIO-LENS: simulation-guided design of miniaturized metalens systems for intravascular OCT imaging

Intravascular optical coherence tomography (OCT) requires ultra-compact optical systems capable of delivering micronscale resolution within catheter diameters below 1 mm. Designing such optics is challenging due to the tight coupling between nanoscale lens geometry, system-level wavefront control, and imaging performance in scattering tissue. We present CARDIO-LENS, a simulation-guided design workflow for flat metasurface lenses (metalenses) tailored to intravascular OCT probes. The workflow integrates nanophotonic unit-cell modeling using rigorous coupled-wave analysis in Lumerical, system-level phase optimization and wavefront analysis in Zemax OpticStudio, and end-to-end imaging evaluation in a realistic vessel scene using Ansys Speos. A TiO2 metalens design is used as an illustrative case study, demonstrating full 0–2π phase coverage with high transmission efficiency and a compact focusing geometry compatible with catheter-scale deployment. Modulation transfer function analysis performed in Zemax shows that the optimized metalens closely reproduces the performance of an ideal diffraction-limited reference under identical system conditions. AI-based tools (e.g. Ansys optiSLang) can further optimize performance and tolerances. This approach accelerates metalens development; for instance, our 0.75 mm-radius design (≈5 mm focal length, NA≈0.15) is expected to focus sharply with >90% efficiency, yielding diffraction-limited OCT imaging. In future work, the same workflow can be extended to multimodal catheter probes (e.g. combined OCT–photoacoustic or hyperspectral imaging).