Tunable optical properties of Ni-Ag and Ni-Au nanoparticles in magneto-plasmonic nanostructures

The combined optical and magnetic properties of magneto-plasmonic nanoparticles makes them ideal candidates for various applications in biomedical fields. In the present work, the optical properties of Ni-Ag and Ni-Au bimetallic alloy nanoparticles with varying sizes 20, 30, 40, 50, and 60 nm of spherical and aspect ratio 2, 3, and 4 of non-spherical nanostructures are studied by the discrete dipole approximation method in the water surrounding medium. Moreover, optical absorption spectra are studied to see the effect of polarization and different alloy compositions. The optical spectra is observed in the range of 371-1280 nm wavelengths and merged in visible-near-infrared region on the electromagnetic spectrum. The result shows that absorption spectra of bimetallic alloy nanoparticles can be well tuned by changing the particle size, aspect ratio's, shapes, and compositions. Furthermore, Ni-Au nanoparticles have enrich optical absorption spectra as compared to Ni-Ag bimetallic nanoparticles. Our study provides a way to analyze and broaden the applications of bimetallic alloy nanoparticles in optical imaging, biomedical field, and therapeutics.