Efficient output coupling of intracavity high harmonic generation

TL;DR

This paper introduces a new diffraction grating technique integrated into dielectric mirrors for efficient coupling of high harmonic radiation from femtosecond enhancement cavities, significantly boosting output power.

Contribution

The novel use of a small-period diffraction grating etched into a dielectric mirror surface enables efficient outcoupling of XUV harmonics from high repetition rate cavities, improving power output.

Findings

Observed harmonics from 3rd to 21st order.

Achieved a dramatic increase in usable harmonic power.

Demonstrated effective coupling of XUV radiation.

Abstract

We demonstrate a novel technique for coupling XUV harmonic radiation out of a femtosecond enhancement cavity. We use a small-period diffraction grating etched directly into the surface of a dielectric mirror. For the fundamental light, this element acts as a high reflector. For harmonic wavelengths, it acts as a diffraction grating, coupling XUV radiation out of the cavity. Using this method, we observed the 3rd through 21st odd harmonics with a dramatic increase in usable power over previous results of high harmonic generation at high repetition rates.