Needle beams and structured space-time wavepackets

TL;DR

This paper explores the properties and applications of needle beams and space-time wavepackets, demonstrating their stable propagation, high homogeneity, and potential for advanced optical functionalities.

Contribution

It introduces a simple model interpreting STWPs as differential needle beams and presents simulations showing their superior spectral and temporal homogeneity.

Findings

Needle beams can achieve higher spectral and temporal homogeneity than focused Gaussian beams.

Interference of femtosecond needle beam arrays enables nondiffracting self-imaging.

STWPs can be rapidly switched and used for orbital angular momentum generation.

Abstract

Recent research on needle beams and space-time wavepackets (STWPs) is presented. Quasi-nondiffracting STWPs propagate at stable spatial and temporal localization over extended distances. In a simple model, STWPs are interpreted as being composed of differential needle beams. Simulations indicate that pulsed Bessel-like needle beams can reach higher spectral and temporal homogeneity compared to spatio-spectrally shaped focused Gaussian beams. The interference of femtosecond needle beam arrays leads to nondiffracting self-imaging in space and time. High-speed switching of STWPs with combined optical systems, orbital angular momentum generation with self-torque and other emerging fields of research are addressed