A novel loss suppression mechanism for optical materials including negative index metamaterials

Optical losses in Metamaterials (MTMs) become a more formidable problem and can obstruct many exciting applications which require very high figures of merit. Many efforts have been proposed to compensate these losses, including using optical gain or the quantum optics coherence. However, these approaches have thus far not been able to resolve the optical losses problem. In this work, we theoretically and experimentally propose a new mechanism for suppressing the optical losses in to significantly reduce the plasmonic losses in optical materials (and negative index metamaterials) based on metals and/or semiconductors. The main advantages of this mechanism of loss suppression include: i) it does not require an additional gain medium; ii) the method is non-destructive; and iii) it does not require any change of the atomic structure of the materials. This method can be applied to any existing or engineered materials to suppress the losses and dramatically improve the optical quality of these materials. This novel mechanism is based on the theory of Bichromatic Loss Suppression, or simply the parametric two-wave coherent coupling technique, rather than the traditional one wave irradiation method. The concept of reducing the optical losses to near-zero is based on, under certain conditions, the solution of non-linear Boltzmann equation (BE) combined with Maxwell equations (MEs). Here, the support wave is provided by a pulsed CO₂ laser at 10.6 μm, and the probe wave at 5.3 μm which is generated from the non-linear infrared crystal silver gallium selenide (AgGaSe₂) by means of the second harmonic generation technique. This study shows that by adjusting the parameters phase shift between the probe and support waves, and their amplitudes, the optical losses can be dramatically reduced to near zero. Experimental work has been conducted in the bulk semiconductor, Zinc Telluride (ZnTe), within the mid-IR frequency range. In this presentatio- , theoretical and experimental results for the reduction in losses are presented.