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

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 Bi 2 Se 3 -Bi 2 Te 3 heterostructures were synthesised by two-step reaction proceeding. The reaction arised in two steps: at first, Bi 2 Se 3 nanosheets were prepared in the solvent of ethylene glycol (EG); secondly, Bi 2 Te 3 was epitaxial grown on the Bi 2 Se 3 nanosheets to form heterostructure materials. The spatial self-phase modulation (SSPM) effect of 457 nm , 532 nm and 671 nm was achieved by dispersing the as-prepared Bi 2 Se 3 -Bi 2 Te 3 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 Bi 2 Se 3 -Bi 2 Te 3 heterostructures might be an effective proposal for photonics devices such as optical switchings, optical modulators, photodetectors, etc.