Toward saturable absorbers for solid state lasers in form of holey fibers filled with single‐wall carbon nanotubes

Abstract

AbstractSaturable absorbers in form of different media (liquids, polymers) with embedded single‐wall carbon nanotubes (SWNTs) already have shown their efficiency in formation of sub‐picosecond pulses in solid state lasers. One of the main limitations is a thermal degradation of such elements in a powerful laser beam. For fiber lasers the best solution would be to get a piece of fiber containing the distributed nanotubes in the core. Unfortunately the fiber treatment temperatures (exceeding 1000 °C in air) are destructive for carbon nanotubes. In this work, we demonstrate a saturable absorber formed via a room temperature filling of the holey fiber with an aqueous SWNT suspension, followed by drying. The evanescent field of the light propagating in the fiber interacts with the thin SWNT films deposited onto the walls of holes. The number of holes can be varied.Thus, we have realized the all‐fiber SWNT saturable absorber. A mode locking regime with the sub‐picosecond output pulses has been realized with this absorber in Er fiber laser.magnified image A cross section of the holey fiber filled with single‐wall carbon nanotubes.