Creating adjustable uniform optical cages through polarization shaping in a low NA optical system

Area of Science:

• Optics
• Photonics
• Optical Engineering

Background:

• Optical cages are crucial for manipulating microscopic particles.
• Generating uniform optical cages, especially in low numerical aperture (NA) systems, presents challenges.
• Existing methods may struggle with trapping large-scale samples or require high NA conditions.

Purpose of the Study:

• To propose a new method for generating uniform optical cages with adjustable properties.
• To investigate the creation of optical cages using superposition of polarized beams in low NA systems.
• To explore the application of these optical cages in optical trapping.

Main Methods:

• Utilizing the superposition of quasi-x-polarized vortex beams (topological charge 1) and quasi-y-polarized beams.
• Employing reversal radiation theory to control the number and position of dark and bright spots.
• Analyzing the influence of axial fields on optical cage quality.

Main Results:

• Demonstrated generation of uniform optical cages with uniformity up to 1, including multiple cages, optical chains, and optical tubes.
• Achieved effective optical cages with uniformity up to 0.695 even at NA values near 0.75.
• Investigated and quantified the impact of axial fields on optical cage quality.

Conclusions:

• The proposed method effectively generates uniform optical cages with tunable characteristics in low NA systems.
• The technique offers a viable solution for optical trapping of large-scale samples, overcoming limitations of high NA focusing.
• This advancement holds potential for applications in manipulating challenging microscopic entities.