Fig. 4

The orthogonal orientation control and navigation of the dye-sensitized microswimmers. a The schematics of the experimental setup where the blue (475 nm) and the red (660 nm) side illumination are used to control the orientation of the microswimmers while the green (550 nm) top illumination is used for imaging. b The angle of the D5 (blue) and SQ2 (red) sensitized microswimmers under fixed 660 nm illumination with rotating 475 nm illumination c The angle of the D5 (blue) and SQ2 (red) sensitized microswimmers under fixed 475 nm illumination with rotating 660 nm illumination. The red and blue arrows in b, c indicate the light propagation direction of the corresponding light. d. The trajectory of SQ2 (red) and D5 (blue) sensitized microswimmers spell ‘r’ and ‘b’ spontaneously as navigated with the blue and red light (scale bar: 20 μm)