CO2-based hollow-core fiber Raman laser with high-pulse energy at 1.95 um

TL;DR

This paper reports a high pulse energy CO2-based hollow-core fiber Raman laser at 1.95 μm, achieving 15.4 μJ pulses with stability and low noise, advancing high-energy 2 μm laser technology.

Contribution

The work introduces a novel high pulse energy Raman laser using a CO2-filled hollow-core fiber pumped by a 1533 nm laser, demonstrating stable operation and potential for high-energy 2 μm applications.

Findings

Achieved 15.4 μJ pulse energy at 1.95 μm

Demonstrated low RIN (<4%) and long-term stability

Explored pressure effects on laser-CO2 absorption overlap

Abstract

In this letter, we present a high pulse energy Raman laser at 1946 nm wavelength directly pumped with a 1533 nm custom-made fiber laser. The Raman laser is based on the stimulated Raman scattering (SRS) in an 8-meter carbon dioxide (CO2) filled nested anti-resonant hollow-core fiber (ARHCF). The low energy phonon emission combined with the inherent SRS process along the low-loss fiber allows the generation of high pulse energy up to 15.4 {\mu}J at atmospheric CO2 pressure. The Raman laser exhibits good long-term stability and low relative intensity noise (RIN) of less than 4%. We also investigate the pressure-dependent overlap of the Raman laser line with the absorption band of CO2 at 2 {\mu}m spectral range. Our results constitute a novel and promising technology towards high energy 2 {\mu}m lasers.