Executive Summary : | Noninvasive monitoring of biological specimens using optical imaging techniques led to continuous innovations in the development of optical sources. Among various noninvasive medical imaging technologies, Optical Coherence Tomography (OCT) is a life transforming, revolutionary technology for the health care industry. At the heart of this technology contains a broadband optical source that enables low-coherence interferometry to obtain cross-sectional images of biological samples. Advanced broadband optical sources having more than octave spanning bandwidths, called supercontinuum (SC) sources, enabled OCT to obtain ultra-high lateral resolution (~few micrometers) 2D, and 3D images that provide, unprecedented monitoring and diagnostic capabilities of many diseases like Glaucoma, Skin cancer, Diabetic retinopathy, Coronary artery stenosis etc. However, the current OCT technology has two major drawbacks. The first one is the lack of early detection of eye and skin related diseases due to poor signal to noise ratio and sensitivity of the acquired images. This is because of the high intensity noise of currently used supercontinuum sources which fundamentally inhibits the desirable shot noise level detection in these systems. The second one is the limited access of the current OCT systems to only high-income developed countries. This is due to their prohibitively high cost (between £30,000 to £100,000), arising majorly from the complex designs of supercontinuum sources. These aspects fundamentally limit not only the performance, but also the access of the current OCT technology to only high-income developed countries. However, there are billions of people with the same healthcare needs from low-income and developing countries. Motivated by this, the goal of this project is to overcome all the above limitations through the development of advanced, much needed, low intensity noise and low-cost fiber-based SC sources. Typically, a SC source consists of a narrow bandwidth (10s of nanometer) laser source and a nonlinear medium to convert the narrow bandwidth pump source into an octave spanning (few 100 nanometer) SC source. Therefore, our proposed method involves 2 important stages: 1) Development of first of its kind low intensity noise, fiber pump laser at the zero dispersion wavelengths of multiple nonlinear optical fiber media, 2) Development of low intensity noise, fiber-based supercontinuum source spanning from ~1.3µm to ~2µm in a most cost-efficient manner, by using above pump fiber laser. The impact of using low-noise supercontinuum sources is enhanced medical diagnostics of OCT where early detection of eye and skin related diseases will be possible. The impact of using cost efficient SC source is the wide accessibility of OCT technology to billions of people, including underserved population from low-income developing countries, across the globe. |