Extended axial irradiances: Barker rings

Area of Science:

• Optics and Photonics
• Microscopy
• Optical Manipulation

Background:

• Achieving extended focal depth is crucial for various imaging and optical manipulation techniques.
• Traditional methods often face limitations in controlling the axial light distribution.
• Barker sequences offer a unique approach to modulate optical fields.

Purpose of the Study:

• To investigate the use of transparent concentric rings encoded with Barker sequences for extending focal depth.
• To analyze the generated axial irradiance distribution for different Barker sequence lengths.
• To demonstrate applications in both imaging and optical trapping.

Main Methods:

• Employing transparent concentric rings patterned with Barker sequences of length L.
• Analyzing the optical field in the paraxial focal plane neighborhood.
• Modulating the axial uniform distribution with sinusoidal variations.

Main Results:

• Extended focal depth is achieved when the Barker length L is congruent to 1 modulo 4, suitable for imaging.
• A bottleneck irradiance distribution is generated when L is congruent to 3 modulo 4, ideal for optical trapping.
• Sinusoidal variations modulate the axial uniform distribution.

Conclusions:

• Barker sequence-encoded masks provide a versatile method for controlling focal depth and axial irradiance.
• The choice of Barker sequence length allows for distinct applications in microscopy and optical trapping.
• This technique offers a novel approach to enhance optical system performance.