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

TL;DR

This paper presents the fabrication of nanothermochromic diffraction gratings using ion beam techniques on VO2, achieving giant switching contrast at telecom wavelengths, with potential for optical memory applications.

Contribution

It introduces a novel ion beam synthesis method for creating nanothermochromic gratings with enhanced diffraction contrast near room temperature.

Findings

Diffraction efficiency increased by over 20 times at 1550 nm.

Pronounced thermal hysteresis observed near room temperature.

Effective site-selective ion beam fabrication demonstrated.

Abstract

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.