Fig. 3
From: Graphene’s nonlinear-optical physics revealed through exponentially growing self-phase modulation
Characteristics of positively chirped input pulses and corresponding broadening results. a Temporal power profile and phase profile of the positively chirped input pulse p2 measured with the frequency-resolved optical gating (FROG) technique (solid curves) and the corresponding fit assuming a quadratic phase profile with \(C_0^{{\mathrm{(p2)}}} = 0.2\) and \(T_{{\mathrm{FWHM}},0}^{{\mathrm{(p2)}}} = 3\) ps (dashed curves). b Broadening factor for input pulse p2 with \(C_0^{{\mathrm{(p2)}}} = 0.2\) as a function of graphene length (in purple). Both the experimental data points and the results from our saturable photoexcited-carrier refraction (SPCR) theory are shown. For comparison we also plot again the broadening factors for input pulse p1 with \(C_0^{{\mathrm{(p1)}}} = - 0.2\) (in black) as shown in Fig. 2a
