Magneto-optical Measurements of Erbium Diffusion Doping on Lithium Niobate

Erbium has been a material of interest in the field of quantum information science as it is a promising candidate for quantum point defects due to its emission at around 1.5 micron telecom wavelengths. Lithium niobate has been explored as a host for quantum point defects, because of its large electro-optic coefficients. The magneto-optical properties of erbium diffusion-doped lithium niobate grown by molecular beam epitaxy and post annealing have been investigated. Photoluminescence and magnetic circular dichroism (MCD) were measured with the sample cooled down in a cryostat and a magnetic response was observed. Most notably, an unexpected symmetric behavior is observed in circular MCD, which is explained by its presence in linear excitation/detection measurements.