Dark solitons manipulation using optical event horizon

We demonstrate that the optical event horizon can provide an effective technique
to actively control the propagation properties of a dark soliton with another weak probe wave.
Careful power adjustment of the probe wave enables the black soliton converted into a gray
one with varying grayness through the nonlinear interaction, corresponding to a nearly
adiabatic variation of the soliton’s speed. The sign of the phase angle for the newly formed
gray soliton at optical event horizon is significantly dependent on the frequency of the
launched probe wave. Linear-stability analysis of dark solitons under the perturbation of a
weak probe wave is performed to clarify the intrinsic mechanism of the nonlinear interaction.
The probe wave manipulated collisional dynamics between both dark solitons are investigated
as an analogue of the combined white-hole and black-hole horizons which provides some
insights into exploring the transition between integrable and non-integrable systems.