MAGNETIC RESPONSE AND NEGATIVE REFRACTION AT OPTICAL FREQUENCIES ON THE BASIS OF ELECTRONIC TRANSITIONS IN RARE-EARTH IONS DOPED CRYSTALS

Magnetic response based on a two-level magnetic dipole transition in rare earth ions doped crystals was studied. Semi-classic theory and Wigner-Eckart theorem were used to calculate the magnetic permeability. It is found that negative permeability can be attained near the transition frequencies. In order to realize simultaneously negative permittivity and negative permeability, an electric dipole transition at the same frequency was also adopted, and a negative refraction region with a bandwidth of 0.57 MHz is demonstrated in (Yb0.02 Sm0.02Y0.96)3Al5O12 crystal. This explores a new route to obtain magnetic response and negative refraction at optical frequencies with nature-existed materials instead of metamaterials.