Physical picture, pattern-control, and detection approach for tightly focused beams: In the view of Fourier optics

TL;DR

This paper explores the nonparaxial propagation of tightly focused beams using Fourier optics, revealing the role of the angular spectrum phase in beam evolution and proposing methods for controlling and detecting the focus spot.

Contribution

It introduces a Fourier optics-based approach to understand, control, and detect the focusing behavior of tightly focused beams, emphasizing the phase of the angular spectrum.

Findings

Phase of the angular spectrum influences beam evolution.

Proposed method for controlling the focus spot.

Detection approach for focused beams.

Abstract

We investigate the mechanism of the nonparaxial propagation of the tightly focused beams in the view of Fourier optics. It shows that it is the phase of the angular spectrum which induces the interesting evolution of the tightly focused beams. Based on the theory of Fourier optics, we propose an approach on controlling and detecting the focusing spot of the tightly focused beams.