Few-Mode Optical Coherence Tomography (FM-OCT)

点击翻译按钮获取中文摘要

Optical coherence tomography (OCT) is an imaging technique that allows infrared light to penetrate a material that scatters the light to obtain a 3D image. It is a non-invasive technology that allows the 3D visualization of tissues at a depth of 2-3mm. The resolution of the images is 100 to 1000 times higher than MRI, CT, and ultrasound. OCT is an important diagnostic method in ophthalmology, thanks to the high transverse resolution where layers can be differentiated and thickness measured. OCT is also investigated as a diagnostic tool for diseases such as diabetic glaucoma, cardiovascular disorders, non-melanoma skin cancer, prostate cancer and esophageal problems. Yet, some aspects of conventional OCT impose significant limitations on disease management, such as limited contrast, difficulty in detecting blood flow in all orientations, or 3D particle motion. However, some ocular diseases involve the formation of cell clusters and/or changes in lateral blood flow in the eye. The measurement of 3D blood flow in the eye could be used for early diagnosis of other neurovascular diseases, such as Alzheimer's disease. Our laboratory has demonstrated OCT with a few mode fiber (FMF) allowing the collection of more light than traditionally collected using a single mode fiber. The FMF is coupled to a modally-specific photonic lantern (MSPL) for mode demiultiplexing. Together, they yield simultaneous OCT images, each acquired from a different propagation mode within tissues (and fiber optics). Real-time image processing of these modes allows increased sensitivity to particles smaller than the resolution, and allow for precise flow measurement in the en face plane. Through this work, we plan to adapt the MSPL to OCT wavelengths and demonstrate the new FM-OCT on phantoms and biological tissues. Several canadian and american industrial partners were approached, and showed great interest in pushing this technology further than its proof-of-concept.