MURI Center for Dynamic Magneto-Optics (DYNAMO)
Technical Report,15 Feb 2014,14 Feb 2020
REGENTS OF THE UNIVERSITY OF MICHIGAN ANN ARBOR United States
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The MURI Center for Dynamic Magneto-Optics DYNAMO was established to investigate magneto-electric phenomena at the molecular level and to evaluate their possible utility for energy conversion. While M-E processes are well-known in bulk magnetic material, and have been studied for energy conversion and sensor technology, magneto-electric rectification, magnetization and harmonic generation at the molecular level in non-magnetic materials have not previously been investigated in any detail. The three nonlinear optical phenomena at the core of this program depend uniquely on the magnetic Lorentz force of light under non-relativistic conditions i.e. at intensities 1018 Wcm2. Dynamic magneto-optic effects are expected to be negligible at low intensities, but it was found that parametric resonance and the exchange of orbital and rotational angular momenta can intensify nonlinearities mediated by the optical Lorentz force at non-relativisticintensities. Torque enhancement was confirmed experimentally in spectra of magneto-electrically scattered light that contained rotational features, confirming the importance of librational motion and low libration frequencies in magneto-electric transitions at the molecular level. The program also developed three different analytic approaches to understand charge separation, magnetization, and harmonic generation a classical torque model, an exact dressed state analysis, and a density matrix treatment which displayed the dependences of M-E processes on transition moments, detuning, relaxation rates, intensity, and polarization.
- Electricity and Magnetism