The Center for Dynamic Magneto-Optics was officially launched in 2014 as a Multi-University Research Initiative (MURI) by ONR/DOD to be administered by AFOSR program manager Dr. Ali Sayir.  The College of Engineering at the University of Michigan has contributed significantly to establishment of this Center, called DYNAMO.  Its main focus is to provide better understanding of phenomena driven by the magnetic field component of light.

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Optical magnetization has received growing attention in the last few years as its relevance to emerging fields like spintronics, quantum information science, optomagnetic data storage, and transformation optics has grown. In most of the aforementioned topics, the optical coupling of light to spins has been via intrinsically weak spin-orbit coupling effects in magnetic media. Yet these light-induced effects were strong enough to support significant applications. Recent experiments have confirmed that Magnetic Dipole (MD) scattering can be induced in many materials with intensities comparable to electric dipole (ED) polarization and that transverse magnetization is possible. It has been found that the combined interactions of dynamic magnetic and electric fields can be parametrically enhanced by over eight orders of magnitude in transparent dielectrics, on an ultrafast timescale, leading to unanticipated phenomena such as magneto-electric energy conversion (MEC).  Consequently, long-term goals of the Center include investigation of mechanisms for magnetic field generation with moderately intense light and  evaluation of  the prospects for direct conversion of light to electricity without the thermodynamic losses typical of photovoltaic technology

A remarkable feature of magneto-electric energy conversion (MEC) is that light can induce voltages between the surfaces of dielectric optical materials, forming an “optical capacitor”.  The process itself requires nonlinear optical response driven by optical E and B fields, and simply produces static charge separation in atoms irradiated with intense light. To generate electrical power using magneto-optics, synchronized electric and magnetic displacement currents in insulators must be exploited.  Then the optical absorption and electron-pair production that typify semiconducting solar cells can be avoided and the associated losses circumvented in principle. Magneto optics has long been considered the poor cousin of electro optics. Yet, in recent years it has been demonstrated that ferromagnetic domains can be flipped with single 100-fs laser pulses.  This suggests that remarkably energetic magnetic interactions can take place. However, the details of dynamic effects involving both the electric (E) and magnetic (B) fields of light remain unexplored, and the shortcomings of conventional nonlinear optical analysis based on the static symmetry of the medium are only now becoming apparent.  EB-driven nonlinearities are capable of modifying the symmetry of media dynamically, and are therefore expected to enable entirely new families of nonlinear optical interactions.

The fundamental objective of this basic research initiative is therefore to uncover, explain, and exploit dynamic magneto-optical processes and materials for new technological capabilities. A particularly important process is the magneto-electric conversion (MEC) process, that in principle accomplishes the transformation of light energy into electricity without generating much heat in transparent insulating materials that offer the prospect of nearly unit efficiency.  Its key advantages can be traced to the evasion of absorptive heating while inducing charge separation in the ground state of atoms or molecules. Surprisingly, coherence of the input light is also not required, so MEC should enable direct conversion of any kind of intense light into electricity whether the input is in the form of sunlight, laser beams, or other forms of directed energy. Magneto-electric conversion would require materials that respond at the intensities available from directed energy sources or sunlight, but the process might offer novel ways of power beaming to support air and space constellations of DOD assets.  This Center will establish the framework required to develop a new and revolutionary class of materials capable of sustained operation of magneto-electric conversion. The objectives of the proposed effort are: (1) to gain an improved understanding of the mechanism of new nonlinear optical effects, (2) to investigate their response to coherent and incoherent radiation, and (3) to guide transformative scientific advances in optical energy conversion. The prerequisite is the understanding of how the magnetic component of light can join forces with an electric field to drive unanticipated optical response. These objectives will be met with a systematic study of dielectric materials designed to furnish exceptional magneto-electric polarizabilities.