Integrated multi-LED array with three-dimensional polymer waveguide for optogenetics

This paper presents a three-dimensional (3-D) flexible micro light emitting diode (μ-LED) array for optogenetics. The array integrates individually addressable μ-LED chips with out-of-plane polymer-based microscale waveguides for deep brain optical stimulation. SU-8 waveguides were fabricated using a backside exposure method. A wafer-level assembly technique was demonstrated, which permits large scale, high-density system integration. The electrical, optical, and mechanical properties of the 3-D multi-LED array were characterized experimentally. This study lays the foundation to achieve a fully implantable optogenetics-based stimulator that enables high spatial resolution and precise stimulation of the target neurons.