Magnetic Dipole Emission Lines in Trivalent Lanthanide Ions

Magnetic dipole (MD) transitions offer a unique opportunity to study light-matter interactions beyond the electric dipole approximation. Modified spontaneous emission from MD transitions can serve as an ideal way to study optical magnetic fields in metamaterials and related nanostructures. While many MD absorption lines have been identified, only a few MD emission lines in solid state systems are widely known. Here we seek to expand the known MD emission lines by calculating all such transitions in the trivalent lanthanide ions. We use intermediate coupling to construct a detailed free-ion Hamiltonian including electrostatic, spin-orbit, two- and three-body, spin-spin, spin-other-orbit, and electrostatically correlated spin-orbit interactions. Determining the free-ion energy levels allows the calculation of ground-state MD absorption lines, and their respective oscillator strengths, as well as spontaneous emission rates for all MD mediated transitions. Many strong MD emission lines are predicted throughout the visible and near infrared spectrum. Corresponding electric quadrupole transitions were also calculated and found to have negligible contribution. If time permits, we will also present direct experimental measurements characterizing these new MD emission lines.