Partial nonlinear reciprocity breaking through ultrafast dynamics in a random photonic medium

We demonstrate that ultrafast nonlinear dynamics gives rise to reciprocity breaking in a random photonic medium. Reciprocity breaking is observed via the suppression of coherent backscattering, a manifestation of weak localization of light. The effect is observed in a pump-probe configuration where the pump induces an ultrafast step-change of the refractive index during the dwell time of the probe light in the material. The dynamical suppression of coherent backscattering is reproduced well by a multiple scattering Monte Carlo simulation. Ultrafast reciprocity breaking provides a distinct mechanism in nonlinear optical media which opens up avenues for the active manipulation of mesoscopic transport, random lasers, and photon localization.Comment: 5 pages, 4 figure

Ultrafast adiabatic control of reciprocity and coherent backscattering in random scattering media

We experimentally demonstrate ultrafast control over reciprocal light paths in random media. The combination of multiple scattering and coherence of light gives rise to strong interference contributions in light transport. An important interference correction to diffusion theory is the coherent backscattering effect, the constructive interference of reciprocal light paths in the backscattering direction. Our experiments show that the phase coherence between these paths can be suppressed by introducing dynamics faster than the photon dwell time. This adiabatic dephasing is of interest for its potential for controlling weak and strong localization and adiabatic storage and release of photonic information