Abstract

The optical soliton can act as a seemingly impenetrable barrier when colliding with a linear wave. Such a collision may lead to a reflection of the probe by the soliton, leading to the analogy to an optical event horizon [1]. However the process can be well understood by generalizing the concept of resonant Cherenkov wave formation from the degenerate case (ω_p=ω_i) to the general four-wave mixing (FWM) non-degenerate case (ω_p ≠ ω_s) [2]. In the collision the soliton (ω_s) interacts with a linear probe wave (ω_p) to generate a frequency-shifted idler ω_p → ω_i as predicted by the resonance condition(mentioned above). The objective of our work is to investigate such a collision in a phase-mismatched quadratic nonlinear crystal, in which the phase-mismatched frequency conversion leads to a self-defocusing effect. This allows for solitons to form in the normal dispersion regime. The Cherenkov waves, or as here the FWM generated idler, are consequently generated at longer wavelengths in the mid-IR [3].

© 2015 IEEE