Noncontact Manipulator for Sedimented/Floating Objects via Laser-Induced Thermocapillary Convection

Noncontact manipulation in liquid environments holds significant applications in micro/nanofluidics, microassembly, micromanufacturing, and microrobotics. Achieving compatibility in manipulating both sedimented and floating objects, as well as independently and synergistically manipulating multiple targets, remains a significant challenge. Here, a noncontact manipulator is developed for both sedimented and floating objects using laser-induced thermocapillary convection. Various strategies are proposed based on the distinct responses of sedimented and floating objects. Predefined scanning and “checkpoint” methods facilitate accurate movements of individual and multiple particles, respectively. Ultrafast programmed scanning and laser multiplexing enable independent manipulation and high-throughput ordered distribution of multiple particles. At the air–liquid interface, “laser cage” and “laser wall” are proposed to serve as effective tools for manipulating floating objects, especially with vision-based closed-loop control. Methods and strategies here do not rely on specific features of targets, solvents, and substrates. Multiple examples, including complex path replication, maze traversal, and precise assembly and disassembly, are demonstrated to validate the feasibility of this manipulator. This work provides a versatile platform and a novel methodology for noncontact manipulation in liquid.