Retrieving the Size of Deep-Subwavelength Objects via Tunable Optical Spin-Orbit Coupling

Area of Science:

• Optics and Photonics
• Nanotechnology
• Materials Science

Background:

• Accurate characterization of nanoscale objects is crucial for advancements in various scientific fields.
• Traditional methods for determining nanoparticle size and shape often require complex algorithms or direct imaging, limiting their applicability.
• Subwavelength metrology presents significant challenges due to diffraction limits.

Purpose of the Study:

• To develop a far-field superresolution nanometrology scheme for retrieving nanoparticle size parameters.
• To enable precise characterization of nanoparticles on a substrate at scales smaller than the wavelength of light.
• To provide a sensitive and efficient method for nanometrology without complex optimization.

Main Methods:

• Illuminating nanoparticles with two plane waves to generate complex local polarization distributions.
• Observing the far-field scattering pattern of light into the substrate.
• Exploiting the controlled induced complex dipole moment, exponential decay of radiated power into the supercritical region, and spin-orbit coupling effects.

Main Results:

• Successfully demonstrated a method for retrieving nanoparticle shape, size, and position directly from far-field scattering patterns.
• Achieved high sensitivity in measurements for nanoparticles significantly smaller than the wavelength of light.
• Eliminated the need for complicated and time-consuming optimization algorithms in the metrology process.

Conclusions:

• The proposed scheme offers a breakthrough in far-field superresolution nanometrology.
• This technique leverages the interaction of vectorial light with nanoparticles for precise characterization.
• The method has the potential to significantly advance nanoscale measurement capabilities.