Integration of neural optical recording and stimulation on minimally invasive, deep-brain implantable CMOS

This thesis describes the development of a minimally invasive integrated platform for all-optical neural stimulation and measurement (OptoSAM). The OptoSAM platform is a single mixed-signal complementary metal-oxide semiconductor (CMOS) chip. After design, the chip is postprocessed to contain the necessary optical filters and emitters to enable both fluorescent detection and neural stimulation. Finally, the chip is packaged in a probe form factor for minimally-invasive implantation into neural tissue. The thesis describes how the OptoSAM is engineered for two applications: optical fluorescent imaging on one hand and optogenetic stimulation on the other. For either application, constraints and tradeoffs are described that guide design specifications. For fluorescent neural detection, this thesis focuses on improvements made in lens-less image reconstruction and optical filtering. It describes circuit design for the lens-less, filter-less fluorescent imaging subsystem and characterizes the resulting imaging performance. The lack of on-chip filters precludes reliable imaging of fluorescent targets both in-vivo and ex-vivo. To address these limitations, the metal-insulator-metal angle sensitive pixel (MIMASP) is introduced, a novel nanophotonic structure that integrates lens-less imaging and optical filtering in an ultrathin (