Dynamic three-dimensional multifocal spots in high numerical-aperture objectives

Area of Science:

• Optics and Photonics
• Microscopy and Imaging

Background:

• Multifocal spots generated by high numerical-aperture (NA) objectives offer rapid, parallel processing for diverse applications.
• Current iterative algorithms for creating three-dimensional (3D) multifocal spots limit their practical utility.

Purpose of the Study:

• To develop a non-iterative method for generating dynamic 3D multifocal spots.
• To enable precise control over the position of each focal spot within the objective's focal volume.

Main Methods:

• Utilized annular subzone phases (ASPs), comprising annular subareas with distinct phase-only distributions for 3D displacement.
• Implemented a non-iterative approach, bypassing the limitations of traditional iterative algorithms.

Main Results:

• Successfully demonstrated the creation of dynamic 3D multifocal spots with individually controllable positions.
• Experimental validation confirmed the feasibility of the ASP-based method for generating tunable multifocal spots.

Conclusions:

• The non-iterative ASP method provides a versatile and efficient approach for generating dynamic 3D multifocal spots.
• This technique holds significant potential for advancing laser 3D fabrication, optical trapping, and high-speed scanned microscopic imaging.