| Autor: |
Lim CK; The Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo , Buffalo, New York 14260, United States., Cho MJ; The Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo , Buffalo, New York 14260, United States., Singh A; The Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo , Buffalo, New York 14260, United States., Li Q; Department of Chemical and Biological Engineering, State University of New York at Buffalo , Buffalo, New York 14260, United States., Kim WJ; The Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo , Buffalo, New York 14260, United States., Jee HS; The Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo , Buffalo, New York 14260, United States., Fillman KL; Department of Chemistry, University of Rochester , Rochester, New York 14627, United States., Carpenter SH; Department of Chemistry, University of Rochester , Rochester, New York 14627, United States., Neidig ML; Department of Chemistry, University of Rochester , Rochester, New York 14627, United States., Baev A; The Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo , Buffalo, New York 14260, United States., Swihart MT; The Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo , Buffalo, New York 14260, United States.; Department of Chemical and Biological Engineering, State University of New York at Buffalo , Buffalo, New York 14260, United States., Prasad PN; The Institute for Lasers, Photonics and Biophotonics, State University of New York at Buffalo , Buffalo, New York 14260, United States. |
| Abstrakt: |
We report the first example of tuning the large magneto-optic activity of a chiral polymer by addition of stable organic biradicals. The spectral dispersion of Verdet constant, which quantifies magneto-optic response, differs substantially between the base polymer and the nanocomposite. We employed a microscopic model, supported by atomistic calculations, to rationalize the behavior of this nanocomposite system. The suggested mechanism involves magnetic coupling between helical conjugated polymer fibrils, with spatially delocalized helical π-electron density, and the high density of spin states provided by the biradical dopants, which leads to synergistic enhancement of magneto-optic response. Our combined experimental and theoretical studies reveal that the manipulation of magnetic coupling in this new class of magneto-optic materials offers an opportunity to tailor the magnitude, sign, and spectral dispersion of the Verdet constant over a broad range of wavelengths, from the UV to the near-IR. This provides a new strategy for creating conformable materials with extraordinary magneto-optic activity, which can ultimately enable new applications requiring spatially and temporally resolved measurement of extremely weak magnetic fields. In particular, magneto-optic materials, presently employed in technologies like optical isolators and optical circulators, could be used in ultrasensitive optical magnetometers. This, in turn, could open a path toward mapping of brain activity via optical magnetoencephalography. |
