Topological insulator Sb2Te3 as an optical media for the generation of ring-shaped beams

Hexagonal nanosheets of Sb2Te3 single crystals with uniform morphology are successfully synthesized through a solvothermal method. We experimentally demonstrate that topological insulator Sb2Te3 as an optical media can be used for the generation of ring- shaped beams based on a giant optical nonlinearity and the effect of graded- index plasma lens. Good propagation properties in free space are exhibited by the generated ring- shaped beam and the dark spot size of ring- shaped beams can be conveniently controlled by adjusting the power of the pump beam. We also find that it is more easily to generate a ring- shaped beam in the high concentration Sb2Te3 dispersion solution and the divergence angle of the ring- shaped beam increases as the concentration of dispersion solution increase. (C) 2014 Optical Society of America