Generation of a controllable multifocal array from a modulated azimuthally polarized beam

Area of Science:

• Optics and Photonics
• Laser Physics
• Nanotechnology

Background:

• Achieving tightly focused light is crucial for high-resolution optical applications.
• Controlling the polarization state of light beams allows for manipulation of focal spot characteristics.
• Previous research has explored various beam profiles and focusing techniques.

Purpose of the Study:

• To investigate the focal spot characteristics of azimuthally polarized beams modulated by different phase plates.
• To design and simulate novel multizone phase plates for generating controllable multifocal arrays.
• To assess the potential of these multifocal arrays for parallel optical recording and imaging.

Main Methods:

• Numerical simulations were employed to analyze focal spot areas.
• Vortex-0-2π-phase plates and π-phase-step plates were used to modulate azimuthally polarized beams.
• Three pupil functions (uniform, Gaussian, and Bessel-Gauss) were considered.
• Theoretical design and numerical simulation of multizone phase plates were performed.

Main Results:

• Azimuthally polarized beams produced smaller focal spot areas compared to radially polarized beams across different pupil functions.
• The study successfully designed and simulated multizone phase plates for generating tight multifocal arrays from azimuthally polarized beams.
• The positions and polarization states of the multifocal arrays were shown to be controllable by adjusting the multizone plate patterns.

Conclusions:

• Azimuthally polarized beams offer advantages in achieving smaller focal spots.
• The developed multizone phase plates provide a novel method for generating controllable multifocal arrays.
• These findings have significant implications for advancing parallel optical recording and imaging technologies.