Versatile Multilayer Metamaterial Nanoparticles with Tailored Optical Constants for Force and Torque Transduction

Area of Science:

• Nanotechnology
• Optical Physics
• Materials Science

Background:

• Optical traps enable precise manipulation of micro- and nanoscale particles.
• Conventional birefringent particles (e.g., quartz, rutile) have optical limitations.
• Widespread application of optical trapping is hindered by material constraints.

Purpose of the Study:

• To develop novel metamaterial nanoparticles with tunable optical properties.
• To overcome the limitations of conventional birefringent materials in optical trapping.
• To demonstrate the application of these nanoparticles as force and torque transducers.

Main Methods:

• Fabrication of multilayer metamaterial nanoparticles using niobium pentoxide (Nb2O5) and silicon dioxide (SiO2).
• Tuning refractive index and birefringence by adjusting layer thickness ratios.
• Utilizing a top-down fabrication process for high-yield production of uniform particles.
• Employing an optical torque wrench to test particle functionality.

Main Results:

• Achieved high birefringence and moderate refractive index with Nb2O5/SiO2 metamaterial nanoparticles.
• Demonstrated successful, high-yield fabrication of uniform, free-floating particles.
• Confirmed particles function as stable joint force and torque transducers in aqueous solutions.
• Showcased controllable optimization for specific characteristics like torque transfer and response time.

Conclusions:

• Multilayer metamaterial nanoparticles offer a versatile platform for optical trapping.
• Customizable optical constants surpass conventional crystalline materials.
• These nanoparticles unlock broader applications and potential of optical trapping technologies.