Non-iterative phase-only modulation method for generating high-uniformity 3D multifocal spots with flexible position control

Abstract

We propose a non-iterative wavefront phase computation method, the crescent segmentation phase (CSP) method that generates 3D multifocal spots with flexible control over their positions. Previously reported segmentation-based work usually introduces diffraction stray light mainly caused by the periodic structures of regional design. Our method reduces the stray light and obtains higher spot uniformity through a simple and effective phase pattern division process. Then we apply the CSP method to the approach of point spread function (PSF) modulation designed for stimulated emission depletion (STED) microscopy. A new phase generation method is proposed that can achieve simultaneous PSF modulation in both lateral and axial directions with only one phase modulation. Our CSP method is suitable for spatial light modulators (SLMs). Furthermore, our approach has potential applications in the fields of laser direct writing, optical data storage, super-resolution imaging, and optogenetics.