Nonlinear optical propagation near the Bragg resonance in heliconical cholesteric liquid crystals.

We show here that the light-induced tuning of the Bragg reflection recently demonstrated in heliconical cholesterics opens new perspectives to nonlinear optical propagation in liquid crystals. We highlight that, by properly adjusting the static electric field that stabilizes the heliconical structure, a dramatic change of the refractive index of the circularly polarized resonant mode can be achieved. Additionally, a stop band for a definite range of light intensity is obtained that can be tuned in order to get the conditions of self-induced transparency.