Ion beam synthesis of nanothermochromic diffraction gratings with giant switching contrast at telecom wavelengths

Johannes Zimmer, Achim Wixforth, Helmut Karl, Hubert J. Krenner

Applied Physics Letters 100, 231911 (Jun 2012) DOI: Applied Physics Letters

Nanothermochromic diffraction gratings based on the metal-insulator transition of VO2 are fabricated by site-selective ion beam implantation in a SiO2 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.