Fig. 2. Phototunable self-oscillations.

a Photograph showing the location and intensity of NIR spot that triggers three basic self-oscillations. The shade of red color enclosed by dashed boxes schematically indicates the intensity of the light. With the same size of the NIR spot, the thresholds of light intensity must be met to generate three self-oscillations (see Supplementary Fig. 6). The threshold required to produce up-and-down oscillation is the highest among the three basic self-oscillations. To gain tilt oscillation, the connection part between the hanging object and the SWFA must be irradiated. b, d, f Snapshots experimentally showing three basic self-oscillations: tilt oscillation (Supplementary Movie 2), rotational oscillation (Supplementary Movie 3), and up-and-down oscillation (Supplementary Movie 4). c, e, g Tilt oscillation, rotational oscillation, and up-and-down oscillation are quantified through tilt angle (θ), rotational angle (α), and displacement (d) with time, respectively. h Photographs showing controllable and reversible switching among the three basic oscillation modes (Supplementary Movie 5). The T-shaped load is used to clearly exhibit self-oscillations. The weight of the hanging object is 62 mg. The intensity of NIR light is ~3.5 W cm⁻² for tilt oscillation and rotational oscillation, and ~5 W cm⁻² for up-and-down oscillation.