Ion beam synthesis of nanothermochromic diffraction gratings with giant   switching contrast at telecom wavelengths
  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. 
Johannes Zimmer, Achim Wixforth, Helmut Karl, Hubert J. Krenner
cond-mat.mtrl-sci cond-mat.other physics.optics