UNS: Fast Focus-scanning Microscopy Using Micron-thick phase Plates Based on High-index Meta-structures

California Institute Of Technology, Pasadena CA

Investigators

Abstract

Abstract Faraon 1512266 Understanding how the brain works is one of the main scientific challenges of this generation. Optical techniques for neural imaging, excitation and recording play a crucial role in deconstructing the neural circuitry. Optical modulation and recording from sets of neurons is enabled by optogenetics and genetically encoded voltage sensors. To fully use this capability, the PI proposes to develop a fast and slim device capable of focusing light in a volume on the same order of magnitude as a cortical column at speeds faster than an action potential and spatial resolution smaller than a neuronal cell body. The enabling technology is the recent invention of dielectric meta-surfaces, structures thinner than a wavelength that allow for unprecedented control of free-space propagating light. The uniqueness of the technology stems from the capability to lithographically place the phase plates in very close proximity (tens of microns) and to actuate them at high speeds using electrostatic forces like in micro electro-mechanical devices (MEMS). If successful, this project will enable devices that could scan many neurons in a cortical column with single action potential temporal resolution, thus resulting in deconstruction of neural circuitry in that column. This interdisciplinary project will provide the opportunity to train a graduate student in nano-photonics and biomicroscopy. The student will simulate and fabricate the devices, will develop a complex microscope setup, and will do two-photon microscopy measurements on brain samples. In addition to graduate student education, undergraduate students will contribute to the project through the SURF program at Caltech. The PI and the graduate student will be involved in an outreach activity with the Navajo Preparatory High School, a native American high school located in Farmington, New Mexico. The activity will consist in travelling to Farmington to teach science lessons, describing the research, and setting up demonstrations for high school students visiting Caltech.