In situ fully vectorial tomography and pupil function retrieval of tightly focused fields

TL;DR

This paper introduces an in situ method for rapid, accurate 3D vectorial reconstruction of tightly focused optical fields and pupil functions, enhancing nano-optics applications.

Contribution

It presents a novel phase-modulated focusing and polarization-split detection technique with an efficient decoding algorithm for 3D vectorial field and pupil function retrieval.

Findings

Achieves approximately 90% accuracy with only 10 frames of 2D measurements.

Reconstruction process takes within 10 seconds, demonstrating efficiency.

Applicable to vectorial field manipulation and adaptive optics in nanoscopy.

Abstract

Tightly focused optical fields are essential in nano-optics, but their applications have been limited by the challenges of accurate yet efficient characterization. In this article, we develop an in situ method for reconstructing the fully vectorial information of tightly focused fields in three-dimensional (3D) space, while simultaneously retrieving the pupil functions. Our approach encodes these fields using phase-modulated focusing and polarization-split detection, followed by decoding through an algorithm based on least-sampling matrix-based Fourier transform and analytically derived gradient. We further employ a focus scanning strategy. When combined with our decoding algorithm, this strategy mitigates the imperfections in the detection path. This approach requires only 10 frames of 2D measurements to realize approximate 90% accuracy in tomography and pupil function retrieval within 10s. Thus, it serves as a robust and convenient tool for the precise characterization and optimization of light at the nanoscale. We apply this technique to fully vectorial field manipulation, adaptive-optics-assisted nanoscopy, and addressing mixed-state problems.