Fully Steerable Symmetric Thermoplasmonic Microswimmers

Area of Science:

• Physics
• Materials Science
• Nanotechnology

Background:

• Microscopic self-propelling particles typically rely on asymmetric structures for directed motion.
• This asymmetry couples orientational Brownian motion with directional movement, limiting persistent travel and leading to diffusive long-term behavior.

Purpose of the Study:

• To demonstrate a novel, completely symmetric thermoplasmonic microswimmer.
• To show that external laser positioning can imprint propulsion direction, decoupling it from inherent particle symmetry.
• To achieve enhanced control and steering capabilities for microswimmer dynamics.

Main Methods:

• Experimental characterization of microswimmer motion.
• Computational simulations of particle dynamics.
• Theoretical analysis of self-thermophoresis-driven propulsion.

Main Results:

• Demonstrated a symmetric thermoplasmonic microswimmer propelled by laser-induced self-thermophoresis.
• Showcased precise external control over propulsion direction, rendering orientational Brownian motion irrelevant.
• Observed enhanced steering capabilities and identified additional noise phenomena.

Conclusions:

• Symmetric microswimmers offer superior control and steering compared to asymmetric designs.
• External laser control overcomes inherent limitations of microswimmer dynamics.
• Findings suggest potential relevance for biological systems and advanced micromanipulation applications.