Transversal optical singularity induced precision measurement of step-nanostructures

Area of Science:

• Optics and Photonics
• Nanotechnology
• Metrology

Background:

• Optical singularities are points of zero intensity where phase and polarization are undefined.
• Vortex beams, like Laguerre-Gaussian modes, possess phase singularities.
• Transversal optical singularities (TOSs) are nano-scale phenomena sensitive to light-matter interactions.

Purpose of the Study:

• To propose and demonstrate the use of TOSs for precise characterization of nanostructures.
• To investigate the scattering of TOSs by a step nanostructure.
• To establish a method for retrieving nanostructure parameters from scattered TOSs.

Main Methods:

• Generation of TOSs via three-wave interference.
• Illumination of a step nanostructure with generated TOSs.
• Analysis of the far-field scattering pattern of the TOSs.

Main Results:

• The scattering direction of the TOSs correlates with the nanostructure's physical parameters.
• Monitoring the spatial coordinates of scattered TOSs allows determination of their propagation direction.
• High-precision retrieval of step nanostructure parameters is achieved.

Conclusions:

• TOSs offer a novel and highly precise method for nanostructure metrology.
• The proposed technique leverages light-matter interaction with singularities for parameter extraction.
• This approach opens possibilities for advanced nanoscale characterization.