Nanostructured potential of optical trapping using a plasmonic nanoblock pair

Area of Science:

• Plasmonics
• Optical Tweezers
• Nanophotonics

Background:

• Optical trapping utilizes focused laser beams to manipulate microscopic particles.
• Plasmon-resonant nanostructures offer unique near-field optical properties.
• Controlling nanoscale potentials is crucial for advanced optical manipulation.

Purpose of the Study:

• To map the two-dimensional optical trapping potentials above a plasmon-resonant gold nanoblock pair.
• To investigate the relationship between near-field optical landscapes and trapping potentials.
• To demonstrate super-resolution optical trapping and enhanced trap stiffness.

Main Methods:

• Two-dimensional mapping of optical trapping potentials.
• Utilizing a 100 nm dielectric particle as a probe.
• Employing a plasmon-resonant gold nanoblock pair with a nanoscale gap.
• Analyzing the effect of incident light polarization.

Main Results:

• Optical trapping potentials exhibit nanoscale spatial structures mirroring the nanoblock pair's near-field.
• Rotating incident polarization by 90° transforms a single potential well into multiple sub-diffraction wells.
• Achieved super-resolution optical trapping capabilities.
• Demonstrated trap stiffness enhancement of approximately three orders of magnitude compared to far-field trapping.

Conclusions:

• Plasmon-resonant nanostructures enable the creation of complex, nanoscale optical trapping potentials.
• Super-resolution optical trapping is achievable by tailoring the near-field interactions.
• Significant enhancement in trap stiffness opens possibilities for highly sensitive measurements and manipulation.