Femtosecond nanometer-sized optical solitons

We report the existence of guided optical solitons of femtosecond duration and nanoscopic mode area. The proposed scheme exploits the structural confinement of light in a low-index subwavelength gap and the nonlinear interaction with a resonantly absorbing medium to achieve stable and ultraconcentrated coherent pulses. Employing full time- and space-dependent Maxwell-Bloch equations, we find that these extremely nonlinear, propagating impulses are quasisolitons, stabilized against dispersion and absorption by self-induced transparency at a laterally constant Rabi frequency.