Linearly polarized, Q-switched Er-doped fiber laser based on reduced   graphene oxide saturable absorber
  We demonstrate generation of linearly polarized pulses from a passively Q-switched Erbium-doped fiber laser. The cavity was designed using only polarization maintaining (PM) fibers and components, resulting in linearly polarized output beam with degree of polarization (DOP) at the level of 97.6%. Reduced graphene oxide (rGO) was used as a saturable absorber for Q-switched operation. The laser was capable of delivering 1.85us pulses with 125nJ pulse energy at 115kHz repetition rate. 
Grzegorz Sobon, Jaroslaw Sotor, Joanna Jagiello, Rafal Kozinski,   Krzysztof Librant, Mariusz Zdrojek, Ludwika Lipinska, and...
physics.optics cond-mat.mtrl-sci