Abstract: As optical coherence tomography (OCT) is extended toward subcellular and deep-tissue target detection, stringent demands are imposed on light source performance. Characterized by ultra-broad spectral coverage, high spatial coherence, and exceptional temporal brightness, supercontinuum (SC) light sources are established as the core physical foundation for overcoming the axial resolution limits of traditional OCT and enabling ultra-high-speed scanning. Despite these optical advantages, the non-linear broadening process of SC generation inherently introduces high relative intensity noise (RIN). This degrades the signal-to-noise ratio and acts as a primary bottleneck for high-sensitivity imaging applications. Recently, researchers have mitigated this issue through structural innovations, such as all-normal dispersion (ANDi) architectures, and system-level optimizations like sub-pixel balanced detection. These improvements allow SC-OCT systems to operate much closer to the shot-noise limit, even at megahertz scanning rates. Consequently, the detection potential across specific spectral bands—including visible light, short-wave infrared, and mid-infrared—has been substantially expanded. This paper reviews the underlying physical mechanisms and recent architectural advancements in suppressing RIN for SC-OCT systems. Furthermore, we discuss its cross-band applications, ranging from the analysis of fundus microstructures and blood oxygen metabolism to deep-tissue imaging and the non-destructive testing of highly scattering materials, with the aim of providing a theoretical reference for medical diagnosis and non-destructive testing technologies in relevant fields.
Keywords: supercontinuum light source; optical coherence tomography; relative intensity noise; medical imaging; ophthalmic imaging
（Acta Laser Biology Sinica, 2026, 35(4): 298-309）