We demonstrate a system for implantable nanophotonic neural probes with custom packaging and peripherals. The probes, which were manufactured on 200mm Si wafers, monolithically integrate SiN waveguides with TiN electrophysiology electrodes and were tested in vivo.

Advances in chip-scale photonic-electronic integration are enabling a new generation of foundry-manufacturable implantable silicon neural probes incorporating nanophotonic waveguides and microelectrodes for optogenetic stimulation and electrophysiological recording in neuroscience research. Further extending neural probe functionalities with integrated microfluidics is a direct approach to achieve neurochemical injection and sampling capabilities. In this work, we use two-photon polymerization 3D printing to integrate microfluidic channels onto photonic neural probes, which include silicon nitride nanophotonic waveguides and grating emitters. The customizability of 3D printing enables a unique geometry of microfluidics that conforms to the shape of each neural probe, enabling integration of microfluidics with a variety of existing neural probes while avoiding the complexities of monolithic microfluidics integration. We demonstrate the photonic and fluidic functionalities of the neural probes via fluorescein injection in agarose gel and photoloysis of caged fluorescein in solution and in fixed brain tissue.

We demonstrate a lensless volumetric imaging microendoscope for deep-brain fluorescence microscopy. It consists of a nanophotonic neural probe for light-sheet illumination and an image fiber bundle for light-field fluorescence collection.

Within the scope of optical system developments for industrial and scientific applications, different requirements have to be taken into account. These include, for example, restrictions regarding available space, protection against environmental influences, or the need for special properties of perspective. The spectral range or bandwidth might impose additional constraints. If available standard lenses do not meet the special requirements which arise, the development of customized optical systems may become necessary.

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