All-optically transformable broad-band transparency and amplification in negative-index films

Negative-index metamaterials (NIMs) exhibit highly unusual optical properties and promise a great variety of unprecedented applications. However, strong optical absorption inherent to such materials imposes severe limitation on such applications. The possibility to overcome this obstacle was proposed based on the coherent energy transfer from the control field to the signal through three-wave mixing, which is accompanied by optical parametric amplification (OPA) in NIMs. It was shown that the transparency exhibits an extraordinary resonance behavior as a function of intensity of the control field and the NIM slab thickness. Basically, such resonances are narrow and the sample remains opaque anywhere beyond the resonance field and sample parameters. Herein, we show that by adjusting the absorption indices for the signal and the idler, the slab can be made transparent and amplifying through the entire negative-index frequency domain and through a broad range of the slab thickness and intensity of the control fields provided that the the product of the intensity and the thickness remains above the certain threshold.