Figure 4. Demonstration of the absence of the photo-induced light artifact in the MEOA.

Bandpass filtered signal recorded in neurobasal medium of 2 neighboring electrodes (indicated on the left in orange) when stimulating through the indicated optrode (indicated on the left in blue) with a pulse width of 500 ms. (a) Output intensity of 5 μW. (b) Output intensity of 120 μW. (c) Bandpass filtered signal recorded in neurobasal medium of 2 neighboring electrodes (in orange) when stimulating directly on the bottom contact with a fiber using a pulse width of 500 ms. Output intensity was 120 μW. (d) Magnification of the stimulation artifact showing the bandpass filtered signal (black) and the raw signal (grey).