Optical cage generated by azimuthal- and radial-variant vector beams

Area of Science:

• Optics and Photonics
• Electromagnetism

Background:

• Vector beams offer unique polarization properties.
• Optical cages are crucial for precise manipulation of microscopic objects.

Purpose of the Study:

• To propose and theoretically demonstrate a method for generating optical cages.
• To investigate the use of azimuthal- and radial-variant vector beams for optical cage formation.

Main Methods:

• Development of a new type of vector beam with tailored polarization states.
• Derivation of an analytical model based on Richards and Wolf's vector diffraction theory.
• Calculation of electromagnetic field and Poynting vector distributions.

Main Results:

• A polarization-controlled optical cage was achieved by adjusting the radial index.
• Uniformity (U) up to 0.7748 and cleanness (C) of zero were obtained.
• A perfect optical cage (U=1, C=0) was demonstrated with amplitude modulation, detailing magnetic field and energy flow.

Conclusions:

• The proposed method effectively generates optical cages with controllable properties.
• Tailoring vector beam polarization offers a versatile approach to optical cage formation.
• These optical cages show potential for advanced optical trapping and high-resolution imaging.