Tailoring nonlinear optical properties of Bi2Se3 through ion irradiation.

Yang Tan,Shengqiang Zhou,Roman Böttger,Xuefeng Yu,Han Zhang,Zhinan Guo,Fang Liu,Zhen Shang,Feng Chen,Jundong Shao

doi:10.1038/srep21799

Abstract

The nonlinear optical property of topological insulator bismuth selenide (Bi2Se3) is found to be well-tailored through ion irradiation by intentionally introducing defects. The increase of the optical modulation depth sensitively depends on the careful selection of the irradiation condition. By implementing the ion irradiated Bi2Se3 film as an optical saturable absorber device for the Q-switched wave-guide laser, an enhanced laser performance has been obtained including narrower pulse duration and higher peak power. Our work provides a new approach of tailoring the nonlinear optical properties of materials through ion irradiation, a well-developed chip-technology, which could find wider applicability to other layered two-dimensional materials beyond topological insulators, such as graphene, MoS2, black phosphours etc.

Highlights

Two-dimensional (2D) materials have received great scientific and technical attentions in research areas of physics, chemistry, and materials sciences[1,2]
2D materials can be integrated with photonic structures such as waveguides and cavities, since the surfaces of 2D materials can be passivated without any dangling bonds
During the Bi2Se3 NPs synthesis, multiple reagents were added into a 25.0 mL two-neck flask with a teflon-coated magnetic stirring bar, including 0.10 g of bismuth (III) nitrate pentahydrate (Bi(NO3)3⋅ 5H2O), 0.05 g of sodium selenite (Na2SeO3), 0.22 g of polyvinyl pyrrolidone (PVP), and 10.0 mL of ethylene glycol (EG)

Summary

Introduction

Two-dimensional (2D) materials have received great scientific and technical attentions in research areas of physics, chemistry, and materials sciences[1,2]. Taking the Q-switched pulsed waveguide laser for example, a waveguide structure with doping of rare-earth ions could be used as the gain medium and 2D materials with the saturable absorption property can be coated onto the waveguide facet as broadband optical saturable absorbers. The modification of the nonlinear optical absorption has shown a direct relation to the irradiation-induced defects in Bi2Se3. Through a careful control of the defect concentration, the saturable absorption of Bi2Se3 was intentionally tailored. The irradiated Bi2Se3 film was integrated with a neodymium doped yttrium aluminum garnet (Nd:YAG) waveguide for the passively Q-switched waveguide laser generation. Based on the modulation of the irradiated Bi2Se3 film, the Q-switched pulses with shorter pulse duration and a higher peak power were obtained, demonstrating the advantages of the irradiation treatment on the optical properties of 2D materials

Methods

Results

Conclusion