SEQUOIA is a European project under the Horizon Europe program. The project unites top research institutes and industrial partners across the continent.
The consortium is working on a quantum Optical Coherence Tomography (OCT) technique that uses specially prepared light to detect sub-micron changes in the retina and thereby detect eye diseases at a very early stage. NKT Photonics is providing a key ultra-stable, broadband laser that is the foundation of the system.
Seeing smaller than ever before
OCT is a non-invasive imaging method that captures detailed, cross-sectional images of tissue using light. While standard OCT devices are widely used in eye care, their axial resolution typically reaches around 1 µm. Many of the earliest signs of retinal disease occur at even smaller, sub-micron scales, making them difficult to detect with existing systems.
By integrating quantum techniques, advanced AI, and ultrafast, highly coherent light, SEQUOIA is testing a quantum OCT system capable of resolving structures down to 0.5 µm – effectively doubling the clarity compared to current state-of-the-art instruments. This enhanced resolution could help clinicians identify diseases sooner and start treatment before irreversible damage occurs.
NKT Photonics’ laser at the core
At the heart of the system is a highly stable, broadband light source developed by NKT Photonics in collaboration with Germany’s Physikalisch-Technische Bundesanstalt (PTB).
An all-normal-dispersion fiber pumped by ultrafast pulses generates a supercontinuum across 700–1400 nm. These pulses are then temporally recompressed to durations of 15–35 fs and passed through a nonlinear crystal to generate UV light around 385 nm with a 20 nm bandwidth.
This laser represents NKT Photonics’ first octave-spanning optical frequency comb, offering extremely low Relative Intensity Noise (<0.055%) and high coherence. Its broad spectral coverage and stability make it ideal for quantum OCT applications, with the potential for further stabilization in carrier-envelope offset and jitter to support high-performance frequency comb operation into the UV range.
While still in development, the project is paving the way for a next-generation quantum OCT platform, with NKT Photonics’ lasers driving new limits in high-resolution optical imaging.
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About Horizon Europe
Horizon Europe is the European Union’s key funding program for research and innovation. It supports the creation and better dispersing of excellent knowledge and technologies.
