Gold-coated tin oxide nanoparticles as potential optical isolator materials: simulation of absorption and Faraday rotation and comparison with micelle templated core-shell nanoparticles

On-chip optical isolation is currently one of the main challenges of photonic integrated circuits. Thus, there is a need for materials that exhibit both Faraday rotation and the ability to be scaled down to match the size constraints of the chip. In this contribution, we assess the potential for SnO2$$\hbox {SnO}_{2}$$@Au core-shell nanoparticles for such materials, through simulation of the Faraday rotation and absorption in comparison to core-shell nanoparticles synthesized by reverse micelle templating. The simulation accurately accounts for the enhanced magneto-optical properties of the tin oxide core due to the surface plasmon resonance effects of the gold shell, which results in a sharper and larger peak in the Verdet constant of core-shell nanoparticles with thicker gold shells. We produced core-shell nanoparticles, examined their absorption and magnetic behaviour and incorporated them into a waveguide setup to assess their feasibility as isolator materials. Though further optimization of the structures are needed, this work shows the potential of such particles to be easily produced and incorporated into cladding materials for optical isolation.