The broader impact/commercial potential of this Small Business Technology Transfer (STTR) Phase I project is to develop an innovative, low-cost light source for an advanced retinal imaging device capable of early diagnosis and monitoring of blinding diseases. Blinding diseases, including diabetic retinopathy and macular degeneration and affect 500 million people worldwide. The proposed technology is aimed at providing a novel non-invasive imaging instrument that can rapidly and reliably assesses retinal health, empowering eye care specialists to better treat and manage blinding diseases. For ophthalmologists, the proposed tool should enable better care and improves outcomes. For patients, it should provide a non-invasive, affordable test, resulting in earlier diagnosis. For payers, it should lower healthcare expenditures by reducing cost of care associated with blindness and by reducing unnecessary or ineffective treatments. The proposed project is to develop a low-cost light source that is suitable for our imaging instrument, which utilize a type of imaging known as optical coherence tomography (OCT). In order to enable commercial production of this industry leading instrument, a new low cost light source needs to be engineered that provides the same type of light as existing lasers, but at a fraction of the cost. To realize the light source, this project will first design and fabricate a plasmonic structural coupler that converts a non-spatial coherent visible light emitted from a low cost LED into a broadband spatial coherent visible light. Meanwhile, the light spatial coherence will be characterized experimentally for examination and optimization. With optimized light sources, the light output will be coupled into visible light optical coherence tomography system for imaging.