Pupil Engineering in a Miniaturized Fluorescent Microscopy Platform Using Binary Diffractive Optics
Joseph Greene MS Thesis Defense(USTC)
Faculty Host:Lei Tian
Committee:Professor Ian Davidson and Professor David Boas
Abstract: Throughout the past decade, an intrigue in developing highly targeted, cost effective solutions has spurred significant investigation in miniaturizing existing optical technologies. Further developments in 3D printing and miniaturized optical manufacturing have inspired rapidly evolving innovations, such as the Boston University head-mounted miniscope for in-vivo neural imaging. Specifically, the miniscope uses off-the-shelf components to monitor fluorescently labelled neural tissue to better identify the link between cognition and neural interactions across a region of the brain. However, it is often a challenge to achieve high-quality images in miniaturized platforms. This thesis specifically aims to address the miniscope’s limited depth-of-field, which prevents adequate observation of target brain volumes. Here, I propose a set of Axicon-based binary diffractive optical elements inserted into the pupil plane of the miniscope designed to extend the depth of field. After conception and theoretical justification, a set of binary diffractive optical elements were fabricated using photolithography and reactive ion etching. Finally, the masks were validated as a pupil engineering solution in a prototype miniscope platform by capturing the 3D iPSF on a variety of fluorescent objects.