Optical nonlinear effects of nickel and cobalt substituents in 1D/2D manganese tungstate/rGO nanocomposite for smart filtering optical radiation

Abstract

The smart filtering effects of Manganese tungstate/reduced Graphene Oxide (MnWO4/rGO,) and Nickel and cobalt doped Manganese tungstate/reduced Graphene Oxide (Mn(1-x+y)NixCoyWO4/rGO) self-assembled urchin like microspheres are explored. Their relevant optical nonlinearities are related with that of pristine MnWO4 nanorods. The third order optical nonlinearities are characterized by a Z-scan analysis with continuous wave regime of 633 nm (He:Ne laser). The highest nonlinear attenuation is attributed to Mn(1-x+y)NixCoyWO4/rGO (5 wt%) microstructures. The intensity dependent absorption β(m/W) and nonlinear index of refraction n2(cm2/W) is determined to be 4.8×10−4 and 8.8×10−7. The maximum attainable optical susceptibility χTOT3 is 16.8×10−8 esu. The morphology of pristine MnWO4 nanorods and urchin like microstructures is evidenced using HRSEM images. The defect D and optical phonon G bands from the Raman signal besides the Agυ1 modes confirms the materialization as nanocomposite.