Insight into the performance of mode-locking with heating SWNT composites

Single-walled carbon nanotubes (SWNTs) have attracted tremendous attentions as saturable absorber (SA) for passive mode locking in fiber lasers, given the fast recovery time, broad spectral range in the near infared and flexible fabrication. For easy handling, SWNTs are always embedded in a polymer for the fabrication of sandwiched-type SA. [1] But when the laser is running for a while, SWNTs can be as a heat sink to deliver the energy to surrounding polymer, leading to the enhanced thermal degradation of materials, which is detrimental to the performance of mode locking. Many works have devoted to improve this situation, among which sol–gel SiO 2 -SWNTs composites offers slight advantage due to higher thermal damage threshold, and mechanical stability. [2] But the influence of the thermal effect on the laser behavior with two kinds of matrixs was not investigated yet. In our work, two classical SAs, PVA-SWNTs and SiO 2 -SWNTs using in fiber laser are given an insight into the performance of mode-locking under different temperature for the first time, which is expected to give a guideline to research on high thermal endurance property SA in fiber lasers.