Research on the linewidth characteristics of the pulse compression laser by stimulated Brillouin scattering through the compact two-cell setup

Stimulated Brillouin scattering (SBS) pulse compression technology obtains high energy, narrow pulse width, and controllable Stokes linewidth output effectively. However, most of the previous research on pulse compression technology focused on the time domain variation characteristics, and the research on the frequency domain linewidth characteristics is less involved. This paper studies the characteristics of linewidth change in the SBS compression process using a compact two-cell generator-amplifier pulse compression setup. It explores the influencing factors of linewidth change. Using FC-770 as the SBS medium, a Stokes pulse output of 424 ps can be obtained under the compact two-cell generator-amplifier pulse compression setup, and the tail modulation and broadening of the pulse waveform while increasing the pump energy are not apparent. The Stokes linewidth can be narrowed from 550 MHz to about 200 MHz. The short phonon lifetime, high gain medium HT-230 and FC-40 further extend the controllable linewidth output range of Stokes pulse. Finally, the effect of the pump linewidth on the Stokes linewidth was further accounted for by two-stage compressions, and two transient SBS pulse compressions could obtain a pulse output of 210 ps.