Low-cost optical splitter for neural stimulations using off-the-shelf ultraviolet adhesives

Abstract. Background: Optical stimulation of the brain is based on optrodes with integrated optical splitters to excite multiple neurons simultaneously. This requires efficient light delivery systems. Aim: In order to satisfy optical requirements, to reduce the fabrication costs, and to obtain less invasive implantation into the brain, we assess a polymer-based microdevice both in theory and experiments. Approach: In addition to design and evaluation of the device using Multiphysics software, to achieve a feasible implementation, we base our fabrication process on off-the-shelf ultraviolet adhesives as the functional material with fascinating optical and mechanical characteristics all together, easy photolithographic-only curing, and no more steps required for common soft lithographic-based materials. Results: Wideband transmission of optical signals over the visible/near-infrared together with uniform splitting of the input power from different light sources has been observed and recorded using an optical setup with acceptable agreement with the simulation outcomes. Conclusions: Our research proposes a flexible and biocompatible optical splitter to be used as a light delivery system for a wide variety of optical stimulation methods in neuroscience studies with fewer or no changes in the design, dimensions, and even exploited materials. So it is a multipurpose device.