Optical switching in VO2 films by below-gap excitation

M. Rini, Z. Hao, R. W. Schoenlein, C. Giannetti, F. Parmigiani, S. Fourmaux, J. C. Kieffer, A. Fujimori, M. Onoda, S. Wall, A. Cavalleri
2008 Applied Physics Letters  
We study the photo-induced insulator-metal transition in VO 2 , correlating threshold and dynamic evolution with excitation wavelength. In high-quality single crystal samples, we find that switching can only be induced with photon energies above the 670-meV gap. This contrasts with the case of polycrystalline films, where formation of the metallic state can also be triggered with photon energies as low as 180 meV, well below the bandgap. Perfection of this process may be conducive to novel
more » ... ucive to novel schemes for optical switches, limiters and detectors, operating at room temperature in the mid-IR.
doi:10.1063/1.2921784 fatcat:qtbjzel44ravngculycj5nrqf4