Light-controlled diamagnetic levitation

<jats:p>Persistent, light-programmed positioning of macroscopic objects without mechanical contact remains an unmet challenge. Optical tweezers offer light-driven control but are typically limited to sub-100-µm objects by force-scaling and photothermal constraints. We demonstrate remote, noncontact motion and positioning of submillimeter objects made of photoswitchable diamagnetic material whose magnetic susceptibility is reversibly modulated by light. Alternating blue/green illumination toggles susceptibility and levitation height, enabling bidirectional, wavelength-encoded translation at ~10 mW cm-2, orders of magnitude below optical-tweezer intensities, and producing motion readily visible to the naked eye without active feedback. Upon removal of illumination, objects remain at their final position stabilized in a potential-energy minimum of a static magnetic field. This light-addressable magnetic actuation extends contactless manipulation beyond the microscopic regime and opens routes to robust positioning and gentle handling in softmatter, bioengineering, and microfabrication settings.</jats:p>