%0 Journal Article %T Ion beam synthesis of nanothermochromic diffraction gratings with giant switching contrast at telecom wavelengths %A Johannes Zimmer %A Achim Wixforth %A Helmut Karl %A Hubert J. Krenner %J Physics %D 2012 %I arXiv %R 10.1063/1.4728110 %X Nanothermochromic diffraction gratings based on the metal-insulator transition of $\mathrm{VO_2}$ are fabricated by site-selective ion beam implantation in a $\mathrm{SiO_2}$ matrix. Gratings were defined either (i) directly by spatially selective ion beam synthesis or (ii) by site-selective deactivation of the phase transition by ion beam induced defects. The strongest increase of the diffracted light intensities was observed at a wavelength of 1550\,nm exceeding a factor of 20 for the selectively deactivated gratings. The observed pronounced thermal hysteresis extending down close to room temperature makes this system ideally suited for optical memory applications. %U http://arxiv.org/abs/1205.5253v2