Figure 1.

(a) Schematic diagram of the multimode optical fibre-coupled probe in [31]. A graded index optical core is coupled with the optical fibre to realise light delivery. A hollow core is used for the in situ observation of neural activities. The shaft tip is shaped to 10 µm diameter for single-neuron manipulation. This figure is reprinted with permission from ref. [31]. (b) Picture of the 3D waveguide optical array in [33]. This figure is reprinted with permission from ref. [33].