Description
Optogenetics has transformed neuroscience by enabling optical control and readout of neuronal activity in vivo with high spatial and temporal precision, opening powerful approaches to dissecting neural circuits and to developing neuroprosthetics and therapies for neurological disorders. Neural probes employ conventionally an optically delivered stimulation, commonly via a grating coupler or micro-LED, while the recording is performed electrically. All-optical approaches to both stimulation and recording offer a complementary route to neuronal control and interrogation, with several distinct advantages like improved scalability, simplified routing for high-density interfaces, enhanced biocompatibility, and the absence of electrical noise and Joule heating. Crucially, optical readout can discriminate spectrally distinct fluorescent reporters, allowing simultaneous interrogation of multiple genetically defined neuronal populations.
Here we present an integrated silicon nitride (Si3N4) photonic platform for efficient optical stimulation of opsin-functionalised neurons. Light couplers were inverse-designed to provide broadband, polarisation-insensitive operation at the specific excitation wavelength and tailored optical field distributions that maximise light delivery to individual neurons. The devices tested by a widefield fluorescence microscope to enable simultaneous optical stimulation and functional imaging of human pluripotent stem cells (h-iPSCs) differentiated in cortical neurons.
These results establish inverse-designed integrated photonics as a promising platform for high-density, multiplexed neurophotonic interfaces, and demonstrate the potential of on-chip photonics for scalable all-optical neural stimulation, functional circuit mapping, and future therapeutic neurotechnology.
| I am the presenting author | Yes |
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