Well, unfortunately it is pretty hard to get any CC0 pictures from optogenetic experiments.. And actually I am not sure what interesting would we see in such pictures haha.
But! I will probably work on optogenetic research myself in few months and thus will be able to provide real-life images and so.. :)

Wait, or are you refering to the fact that the images used in this article are not sourced? Well, that is because I created them.. :D And those that I did not are referenced.