Tapered Optical Fibers for Optogenetics: Ray Tracing Modeling

We present a Ray Tracing model of tapered optical fibers (TF), recently proposed for both wide-volume and site- selective optical control of neural activity [1]. Light-delivery properties of TFs are computationally investigated by identifying the emitting region of the taper and the resulting output angles. This is done in two alternative light coupling modes:i) injecting light within the entire acceptance angle of the optical fiber, generating light output from almost the entire taper, andii) selecting a specific input angle, therefore allowing light delivery from a specific portion of the TF. In both cases a good agreement with previously reported experimental data has been obtained, letting us envision that the proposed approach can be used to study the mode-division demultiplexing properties of TFs, representing an important tool to design optogenetics experimentsin vivowith TFs.