High peak-power 2.1-{\mu}m femtosecond Holmium amplifier at 100 kHz

TL;DR

This paper presents a high peak-power, 97-fs femtosecond laser system at 2.1 μm with 525 MW peak power and 100 kHz repetition rate, enabling advanced applications in the short-wave infrared region.

Contribution

It introduces a novel Holmium-doped CALGO amplifier system operating in CPA scheme with nonlinear compression, achieving unprecedented power and pulse duration in this wavelength range.

Findings

Achieved 525 MW peak power at 2.1 μm

Generated micro plasma in ambient air demonstrating high intensity

Bridged the gap between low-repetition and high-power MHz lasers

Abstract

High-power ultrafast laser sources in the short-wave infrared region are of great interest for numerous applications, including secondary sources of radiation and processing of materials commonly opaque in the near-infrared region. In this wavelength region, direct laser amplification around 2.1-{\mu}m wavelength within the atmospheric transparency window is particularly attractive for realizing compact and efficient high-power lasers. However, this wavelength region was widely underrepresented in femtosecond laser technology so far. Here, we report on a 2.1-{\mu}m laser system delivering 97-fs pulses with an unprecedented combination of high peak power of 525 MW and high repetition rate of 100 kHz. The amplifier system consists of a mode-locked oscillator seeding a regenerative amplifier (RA) using the novel broadband material Holmium (Ho)-doped CaAlGdO4 (CALGO), operating in the chirped pulse amplification (CPA) scheme and a nonlinear compression stage based on a Herriott-type multi-pass cell (MPC) with bulk material. We demonstrate the potential of this unique laser system by generating a micro plasma in ambient air, demonstrating its high intensity for future plasma-driven secondary sources. This system bridges the gap between conventional 1-to-10 kHz amplifiers and high-power MHz laser oscillators in this attractive wavelength range.