Optical Limiting in Cu/CuO Nanostructures Formed by Magnetic Field-Assisted Anodization

The recently developed magnetic field-assisted electroless anodization technique enables more morphological tunability by expanding the parameter space available during nanostructure synthesis and limiting the effects of copper electromigration. We synthesized CuO nanodendrites, nanowalls and nanospheres on both transparent and non-transparent substrates using the magnetic field-assisted anodization of copper foils and vacuum deposited Cu thin films on glass substrates respectively. Non-linear optical characterization of the resulting partially transparent Cu/CuO nanostructures on glass substrates revealed clear optical limiting behavior. When the fluence of the incident 800 nm radiation from a Ti:sapphire laser was increased from 20 mJ cm⁻² to 2 J cm⁻², the optical transmittance of the Cu/CuO nanostructures decreased by nearly an order of magnitude.