Broadband nonlinear optical response in Bi2Se3-Bi2Te3 heterostructure and its application in all-optical switching

Qingkai Wang,Yuanjiang Xiang,Leiming Wu,Xinghua Wu

doi:10.1063/1.5082725

Qingkai Wang, Yuanjiang Xiang + Show 2 more

Open Access

https://doi.org/10.1063/1.5082725

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Journal: AIP Advances	Publication Date: Feb 1, 2019
Citations: 20	License type: cc-by

Affiliation: Jiujiang University, Shenzhen University

Abstract

Compared with homogeneous two-dimensional materials, two-dimensional nanomaterial heterostructures which consist of different kinds of two-dimensional materials exhibit stronger light-matter interaction. The topological insulator of Bi2Se3-Bi2Te3 heterostructures were synthesised by two-step reaction proceeding. The reaction arised in two steps: at first, Bi2Se3 nanosheets were prepared in the solvent of ethylene glycol (EG); secondly, Bi2Te3 was epitaxial grown on the Bi2Se3 nanosheets to form heterostructure materials. The spatial self-phase modulation (SSPM) effect of 457nm, 532nm and 671nm was achieved by dispersing the as-prepared Bi2Se3-Bi2Te3 heterostructure materials into ethanol as an optical medium. Furthermore, based on the effect of SSPM, a device called all-optical switching was also realized. As an interesting nonlinear optical materials, topological insulator Bi2Se3-Bi2Te3 heterostructures might be an effective proposal for photonics devices such as optical switchings, optical modulators, photodetectors, etc.

Highlights

Topological insulator materials represented by Bi2Te3, Bi2Se3 and Sb2Te3 is a new type of two-dimensional nanomaterials with special energy band structure
As a new kind of interesting optical materials, the optical properties and especially nonlinear optical properties of the heterostructures formed by topological insulator materials deserves our explorations and researches
The spatial self-phase modulation effect has been successfully observed in two-dimensional nanomaterials including graphene, transition metal dichalcogenide, black phosphorus and topological insulator materials

Summary

INTRODUCTION

Topological insulator materials represented by Bi2Te3, Bi2Se3 and Sb2Te3 is a new type of two-dimensional nanomaterials with special energy band structure. There is a certain energy band gap between the conduction band and the valence band inside the topological insulators. The spatial self-phase modulation effect has been successfully observed in two-dimensional nanomaterials including graphene, transition metal dichalcogenide, black phosphorus and topological insulator materials.. Using 532nm continuous wave laser beams as light source, Wang et al observed an obvious spatial self-phase modulation effect in the graphene dispersion, and deduced the nonlinear refractive index of the graphene to be n2≈10-5cm2W-1, and the third-order nonlinear susceptibility to be χ(3) ≈ 10-3 (e.s.u.).. The signal beam with weak light intensity can be modulated by adjusting the control beam with strong light intensity He et al achieved tri-phase all-optical switching by using the topological insulator materials Bi2Se3 dispersion as an optical medium.. The spatial self-phase modulation effect of 457nm, 532nm and 671nm was achieved by dispersing the as-synthesized Bi2Se3-Bi2Te3 heterostructure materials into ethanol solution as an optical medium. By adjusting the light intensity of the control beam, the spatial light intensity distribution of the signal beam can be modulated conveniently

SYNTHESIS AND CHARACTERIZATION OF Bi2Se3-Bi2Te3 HETEROSTRUCTURE NANOSHEETS

BROADBAND NONLINEAR OPTICAL PROPERTIES AND OPTICAL SWITCHING

CONCLUSIONS