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Register a new userMicro-scale opto-thermo-mechanical actuation in the dry adhesive regime
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Realizing optical manipulation of microscopic objects is crucial in the research fields of life science, condensed matter physics and physical chemistry. In non-liquid environments, this task is commonly regarded as difficult due to strong adhesive surface force ($simmurm N$) between solid interfaces that makes tiny optical driven force ($simrm pN$) insignificant. Here, by recognizing the microscopic interaction mechanism between friction force -- the parallel component of surface force on the contact surface -- and thermoelastic waves induced by pulsed optical absorption, we establish a general principle enabling the actuation of micro-objects on dry frictional surfaces based on the opto-thermo-mechanical effects. Theoretically, we predict that nanosecond pulsed optical absorption with mW-scale peak power is sufficient to tame $murm N$-scale friction force. Experimentally, we demonstrate that two-dimensional spiral motion of gold plates on micro-fibers driven by a nanosecond pulsed laser, and reveal the specific rules of motion control. Our results pave the way for future development of micro-scale actuators in nonliquid environments.
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