ERI: RUI: Wavefront shaping through flexible multicore fiber bundles for coherent light focusing and imaging in neurophotonics

Harvey Mudd College, Claremont CA

Investigators

Abstract

The goal of this Engineering Research Initiation(ERI) project is to develop an improved method of delivering light to the brain for imaging and stimulating brain activity. Light is a powerful tool for probing the brain and can be used to monitor the firing of neurons or directly activate neurons using optogenetics. Optical wavefront shaping techniques can enable deeper light penetration in the brain. However, these techniques are stymied because it is challenging to deliver the shaped light to the brain. This project addresses this challenge by developing a new system which leverages fiber bundles and optical wavefront shaping to reliably deliver shaped light to the brain, even when the fiber bundle is moving. The outcomes of the research will provide new tools for neuroscientists to deliver shaped light to the brain, enabling better experiments in the research laboratory and paving the way for future clinical applications. The broader impacts of the project include research opportunities for undergraduate students at Harvey Mudd, providing tightly integrated educational opportunities in scientific research methods, optical system design, and neurophotonics. In addition, the PI will develop new educational resources to broaden access to optics through wavefront shaping simulations in Python-based Jupyter notebooks and low-cost lab experiments exploring optical fibers and light matter interactions in scattering media. Multicore fibers offer an attractive way to deliver light to regions of interest in the brain but are challenging to use in practical applications due to core-dependent phase delays which are impacted by a variety of physical and environmental factors such as movement and temperature fluctuations. The project will address this challenge by developing methods to correct the phase distortion of the multicore fiber without requiring access to the distal end, enabling shaped wavefronts to be flexibly delivered into deep tissue even when the core-to-core phase delays are dynamically changing. The research plan is divided into two major tasks: (1) developing a low-coherence interferometry system to measure the phase distortion of the multicore fiber and characterizing key performance metrics such as temporal response and phase sensitivity and (2) using the low-coherence interferometry system with wavefront shaping to correct for the phase delay in the multicore fiber and create desired wavefronts beyond the distal tip of the fiber. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.