Saturable absorption optimization of silica protected thin Sb2Te3 layers towards super-resolution applications

Abstract

Sb2Te3 thin films are very promising candidates for nonlinear optics and several applications including super-resolution and nano-photoinscription. This work aims to offer a detailed study of the preparation of the thin films and their nonlinear optical properties under nanosecond laser excitation. Thin Sb2Te3 films have been deposited by the electron beam deposition technique. The films have been protected by a thin silica layer, then annealed in order to enhance their nonlinearities by material crystallization. The annealing has been optimized by simultaneously recording the X-Ray diffraction diagrams. After this optimization, the annealing could be safely performed by heating in an oven. The nonlinear optical properties of the Sb2Te3 thin films have been studied by means of the Z-scan technique employing 11 ns laser pulses at 1064 nm and 532 nm. High nonlinear absorption has been found showing the possibility to employ these materials for super-resolution, mode-locking and other applications.