Ultrashort intense-field optical vortices produced with laser-etched mirrors

TL;DR

This paper presents a practical method to generate ultrashort, high-intensity optical vortices by laser-etching gratings into gold mirrors, enabling applications in high-power laser systems.

Contribution

It introduces a laser-etching technique to produce holographic gratings on mirrors for creating ultrashort optical vortices with high damage thresholds.

Findings

Etched gratings produce vortices with minimal intensity loss.

The method withstands laser intensities up to 10^12 W/cm2.

The gratings effectively compensate angular dispersion in a 2f-2f setup.

Abstract

We introduce a simple and practical method to create ultrashort intense optical vortices for applications involving high-intensity lasers. Our method utilizes femtosecond laser pulses to laser-etch grating lines into laser-quality gold mirrors. These grating lines holographically encode an optical vortex. We derive mathematical equations for each individual grating line to be etched, for any desired (integer) topological charge. We investigate the smoothness of the etched grooves. We show that they are smooth enough to produce optical vortices with an intensity that is only a few percent lower than in the ideal case. We demonstrate that the etched gratings can be used in a folded version of our 2f-2f setup [Mariyenko et al., Opt. Express 19, 7599 (2005)] to compensate angular dispersion. Lastly, we show that the etched gratings withstand intensities of up to 10^12 W/cm2.