Enhanced Verdet constant via gold coated iron oxide nanoparticles and via change in host medium

The Faraday Effect is the rotation of linearly polarized light when the light enters a material under the influence of a magnetic field that is applied parallel to the direction of propagation of light. Applications of the Faraday Effect include optical isolator, electrical current sensor, magnetic field sensor, etc. The Faraday Effect can be used in bulk samples and in optical fibers to sense an electrical current or a magnetic field. Verdet constant is typically used to quantify the Faraday Effect. Research that has been conducted in this area has shown that water doped with gold coated iron oxide nanoparticles increased the Verdet constant of water. Other research showed that doping PMVS with Janus nanoparticles increased the Verdet constant as well. The research presented in this work improves on prior research by being the first to show the improvement of Verdet constant by doping of gamma-Fe2O 3:Au nanoparticles into various host media: PMMA, MMA, styrene, and polystyrene. The work also demonstrates how the index of refraction of the host medium, resonant wavelength, and the Verdet constant are related. The Verdet constant of MMA is reported for the first time in this work.;The experimental setup, used in this research, was calibrated with SF-57 and BK-7 standard glass samples. By doping the host samples with gamma-Fe 2O3:Au nanoparticles, an increase in Verdet constant ranging from 93% for doped water at an incident wavelength of 633 nm to 523% for doped styrene at an incident wavelength of 473 nm were observed. The concentration of gamma-Fe2O3:Au nanoparticles was kept at 0.03 % (w/w) in order to observe the effect of the host medium and the wavelength of laser on the Verdet constant. Wavelengths of laser used were 633 nm, 532 nm, and 473 nm. Maximum improvement in Verdet constant of 523% was observed for styrene doped with 0.03 % (w/w) of gamma-Fe2O3:Au nanoparticles at an incident wavelength of 473 nm. Verdet constant improvement appears to have been caused by surface plasmon resonance of the gold coating and magneto optic effect of the iron core of the nanoparticle.