This Materials World Network project focuses on the development of new magnetic materials with strong nonlinear magnetic susceptibility. Its aim is to enhance the nonlinear performance of ferrite garnet films by stress generation, compositional gradients and control of the surface contribution to harmonic generation in the presence of photon trapping. Special emphasis is placed on magnetization-induced second and third-harmonic generation in a photonic crystal environment. The project is a collaborative effort between Moscow State University (Oleg Aktsipetrov) and Michigan Technological University (Miguel Levy) that brings together the expertise in ultrafast nonlinear optics of the Moscow group and in integrated (on-chip) magneto-photonic crystal technology and magnetic garnet sputter film-growth of the Michigan group. The intellectual merit of the proposed activity is to bring together disparate contributions to the optical response of a materials system in order to enhance its magnetization-induced nonlinear properties. Inversion symmetry breaking responsible for surface second harmonic generation joins with the light-matter interaction enhancing properties of slow-light to produce strong nonlinear effects. Special attention is paid to increasing local non-uniformities at the unit cell level near the surface to enhance the high-order magnetic susceptibility responsible for harmonic generation. This combination of material and geometrical effects brings to bear through RF-magnetron sputter deposition and the formation of sub-micron surface structures by focused ion beam milling to leverage the strain contribution to the nonlinear response. Symmetry breaking mechanisms and other effects responsible for magnetization-induced harmonic generation are addressed experimentally and theoretically.
Modern photonics and optoelectronics demand strong miniaturization of devices and increases in their operational speed and cost reduction. This activity contributes to this goal by furthering the development of new material structures with strong magnetically-induced nonlinear properties. Magnetization-induced second harmonic generation has become an extremely promising diagnostic tool for the study of grain boundaries and magnetic domain structure for novel computer memory devices based on giant magnetoresistance. This project aims to wed photon trapping and the development of novel materials systems to augment the resolution of this technology to the sub-micron regime. The project also works together with local area high-school teachers to bring information about the role of nanotechnology in optics to high school students. Michigan Tech uses its associations with schools that have high percentages of students from groups underrepresented in science and engineering to widen the scope of the outreach program of demonstrations taken to the high schools, including the Detroit Academy at Cass Technical High School and the Keweenaw Bay Indian Community in the western Upper Peninsula. The activity also involves high school women in science discovery projects in optics and magneto-optics. This effort is coordinated through the Women in Engineering Summer Youth Program offered by Michigan Tech. The international exchange of researchers from Russia and the U.S. is expected to enrich the education component for both graduate and undergraduate students participating in the project.
This award is co-funded with the Office of International Science and Engineering.