Nonlinear optical waveguides in As_2S_3-Ag_2S chalcogenide glass thin films

J M P Almeida,E C Barbano,C B Arnold,L Misoguti,C R Mendonça

doi:10.1364/ome.7.000093

Abstract

Chalcogenide glasses (ChGs) are promising materials for nonlinear optical applications due to their elevated third-order optical susceptibility. Nonetheless, oxidation and photorefractive effects make the characterization and processing of this class of materials an intricate process. Employing ultrashort laser pulses, we were able to investigate the optical nonlinearities of As2S3 thin films doped with Ag2S nanocrystals, as well as produce channel waveguides. The results showed that the nonlinear refractive indexes of these films are in the order of 2.3-5.2 x 10−18 m2/W at wavelengths in the range of 775-1600 nm. Such film revealed to be proper for the development of nonlinear optical devices, since we have demonstrated the functionality of an 8.7 mm long waveguide for spectral broadening femtosecond IR pulses.

Highlights

The large interest in nonlinear optical materials has been motivated by their potential use in all-optical devices
We were able to investigate the optical nonlinearities of As2S3 thin films doped with Ag2S nanocrystals, as well as produce channel waveguides
The results showed that the nonlinear refractive indexes of these films are in the order of 2.3-5.2 x 10−18 m2/W at wavelengths in the range of 775-1600 nm

Summary

Introduction

The large interest in nonlinear optical materials has been motivated by their potential use in all-optical devices. On account of the chemical nature of the elements, their nonlinear optical properties are expected to be at least one order of magnitude higher than oxide glasses [1, 2]. Arsenic trisulfide is an interesting ChG due to its photosensitive properties and flexibility to be synthetized by several routes. There are preparation methods that aim at bulk materials, such as melt-quenching, and at thin films, in which thermal evaporation, sputtering and solution processing techniques have been employed [2, 3]. Many of the photoinduced effects in ChGs are more pronounced in thin films rather than bulk glasses [1]. Silver photodoping of As2S3 films improves the material photosensibility [6]

Methods

Results

Conclusion