Thermal nonlinear refractive index of graphene based saturable absorber in mode-locked fiber lasers

Photonic-crystal-based broadband graphene saturable absorber

“…1,2 The difference from bulk graphite crystal induces unusual nonlinear optical (NLO) properties. 3,4 It can generate electron-hole pairs upon laser excitation at any wavelength  which makes it a progressive solution to ultrafast saturable absorption (SA) [5][6][7][8][9] and optical limiting. 10,11 However, small NLO-coefficient values in natural materials restrict NLO applications to high intensity thresholds.…”