Symmetric sub-diffraction focusing via hybrid Airy-superimposed vector beams

Area of Science:

• Optics and Photonics
• Laser Physics
• Nanotechnology

Background:

• Conventional optical systems are limited by the diffraction limit, restricting resolution in imaging and manipulation.
• Achieving sub-diffraction focusing is crucial for applications requiring high spatial precision.

Purpose of the Study:

• To propose and investigate a novel class of beams, hybrid Airy-superimposed vector beams (HASVBs).
• To demonstrate the capability of HASVBs to generate sub-diffraction focal spots beyond the classical limit.
• To analyze the tunability and parameter dependence of these focal spots.

Main Methods:

• Utilizing Richards-Wolf vector diffraction theory for numerical simulations.
• Constructing HASVBs by superposing inverse circular Airy and circular Airy beams.
• Systematically analyzing the effects of beam parameters (main-ring radius, scaling factor, decay factor) and phase difference.

Main Results:

• HASVBs successfully generate symmetric sub-diffraction focal spots, breaking the diffraction limit in transverse dimensions.
• Focal spot shape is tunable from elliptical to circular symmetry by adjusting the initial phase difference.
• Needle-like longitudinal intensity profiles are observed near the focal region.
• Optimal sub-diffraction focal spots can be achieved by tuning beam parameters for specific numerical apertures.

Conclusions:

• HASVBs offer a viable method for creating sub-diffraction focal spots, overcoming the conventional diffraction limit.
• The tunability of HASVBs allows for precise control over focal spot characteristics.
• These beams hold significant potential for super-resolution imaging, direct laser writing, and optical manipulation applications.