^pLaboratory;
of;
Weak;
Light;
Nonlinear;
Photonics,;
Ministry;
of;
Education;
Teda;
Applied;
Physics;
School;
and;
School;
of;
Physics,;
Nankai;
University,;
Tianjin;
300071,;
China;
^pof;
Physics;
and;
Optoelectronics,;
Taiyuan;
University;
of;
Technology,;
Taiyuan;
030024,;
China;
^pLaboratory;
of;
Functlonal;
Polymer;
Materials;
and;
Center;
for;
Nanoscale;
Science;
&;
Technology,;
Institute;
of;
Polymer;
Chemistry,;
College;
of;
Chemistry,;
Nankai;
University,;
Tianjin;
300071,;
China;
graphene; nonlinear; optical; properties; optical; limiting; saturable; absorber; graphene; oxide;