MEMS tools with laser diodes as integrated light sources for chronic optical stimulation of neuronal activity in brain tissue

Inhalt:
This paper reports on the fabrication and characterization of two miniaturized optical tools with integrated bare laser diodes (LDs) and optical fibers targeting the chronic implantation in small animals. The smaller, so-called integrated device with a single LD measures only 780 µm x 2.5 mm. The second, modular device variant (3.1 x 5 mm2) carries optical fibers and LDs on two separate chips. The removable module carrying the LDs is aligned to the optical fibers on a common substrate, and fixed using small magnets. The use of bare LD chips as light sources guarantees enough optical power to stimulate electrophysiological activity in optogenetically modified neurons. Both design variants reliably achieved >70% coupling efficiency between LD chips and fibers.