Spatial modulation instability driven by light-enhanced nonlinearitiesin semiconductor CdZnTe:V crystals

We present the experimental observation of spatial modulation instability in photorefractive semiconductor crystals (CdZnTe:V), where the optical nonlinear effects are enhanced by light. We find that the total refractive index change can be expressed as sum of a uniform index change, which can exceed the value of 0.003, and a local index change which is limited to ≈ 1.6 × 10 − 4 . However, only the later, arising from the intensity-enhanced photorefractive effect, contributes to the formation of the modulation instability. Finally, we find that the refractive index change experiences large temporal fluctuations induced by the combination of uniform cw illumination and applied electric field.