Elastic light scattering spectroscopy (ELSS) has been proven as a powerful tool in characterizing tissue native structures with superb sensitivity. As a widely used technique, optical coherence tomography (OCT) would have been well suited for ELSS measurement by using a broadband light source. However, OCT-based ELSS is largely hampered by the limited k-space spectral bandwidth from all existing OCT systems. To overcome this barrier, we report a simple all fiber-based setup to implement dual-channel visible and near infrared (NIR) optical coherence tomography (vnOCT) for human retinal imaging, bridging over 300nm spectral gap. Remarkably, we discovered a newly available fiber that supports single-mode propagation and maintains high interference efficiency for both visible and NIR light with fringe visibility of 97% and 90%, respectively, which was previously considered impossible to use the same fiber components for such a broad range of wavelengths. Longitudinal chromatic aberration from the eye is corrected by a custom-designed achromatizing lens. As retinal imaging being an important OCT application, we demonstrated vnOCT on human retina and further developed robust ELSS analysis method to quantify spectroscopic contrast in several import layers of human retina. This vnOCT platform and method of ELSS analysis open new opportunities in understanding structure-function relationship in the human retina and in exploring new biomarkers for retinal diseases.
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