Chromatic optical coherence tomography for high-resolution deep tissue imaging

Achieving clear and deep tissue imaging with optical coherence tomography (OCT) necessitates the simultaneous optimization of three critical factors: high resolution, extended depth of focus (DOF), and high signal-to-noise ratio (SNR). Conventional OCT systems often compromise one or more of these factors, due to inherent trade-offs in optical design and noise management. To address these limitations, we present a chromatic OCT system that simultaneously optimizes all three parameters. The system achieves an isotropic spatial resolution of 2 to 3 μm by leveraging a broad bandwidth light source and high-numerical-aperture optics with a pronounced chromatic focal shift, which enables up to a sevenfold DOF extension. Additionally, a novel noise-gating algorithm suppresses system-inherent noise, sidelobe artifacts, and multiple scattering effects, significantly enhancing the SNR. Comparative simulations and experiments demonstrate that the proposed chromatic OCT outperforms conventional high-resolution systems by maintaining superior resolution and SNR over an extended imaging range. These advancements establish chromatic OCT as a powerful tool for high-resolution, deep tissue imaging in biomedical applications, offering improved diagnostic capabilities.