Magnesium diboride (MgB₂) as a saturable absorber for a ytterbium-doped Q-switched fiber laser

Magnesium diboride (MgB₂) is a well-known superconductor at temperatures below 39 K. At higher temperatures, it behaves as a lossy material. In this paper, we examine the performance of MgB₂ nano-particles as saturable absorber in a ytterbium-doped fiber ring laser at room temperature: we show that the nano-particles can produce pulses between 200 and 1700 ns. The dynamics of the saturable absorber are both examined as a stand-alone saturable absorber and in combination with an acousto-optic modulator. We believe, to the best of our knowledge, that this is the first time that MgB₂ is used as a saturable absorber in a Q-switched laser.