A robust and tuneable mid-infrared optical switch enabled by bulk Dirac fermions

Chunhui Zhu; Fengqiu Wang; Yafei Meng; Xiang Yuan; Faxian Xiu; Hongyu Luo; Yazhou Wang; Jianfeng Li; Xinjie Lv; Liang He; Yongbing Xu; Junfeng Liu; Chao Zhang; Yi Shi; Rong Zhang; Shining Zhu

doi:10.1038/ncomms14111

A robust and tuneable mid-infrared optical switch enabled by bulk Dirac fermions

Nat Commun. 2017 Jan 20:8:14111. doi: 10.1038/ncomms14111.

Authors

Chunhui Zhu^{1

2}, Fengqiu Wang^{1

2}, Yafei Meng^{1

2}, Xiang Yuan^{2

3}, Faxian Xiu^{2

3}, Hongyu Luo⁴, Yazhou Wang⁴, Jianfeng Li⁴, Xinjie Lv^{2

5}, Liang He^{1

2}, Yongbing Xu^{1

2}, Junfeng Liu⁶, Chao Zhang⁷, Yi Shi^{1

2}, Rong Zhang^{1

2}, Shining Zhu^{2

5}

Affiliations

¹ School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, China.
² Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China.
³ State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China.
⁴ School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054, China.
⁵ National Laboratory of Solid State Microstructures and School of Physics, Nanjing University, Nanjing 210093, China.
⁶ Department of Physics, South University of Science and Technology of China, Shenzhen 518055, China.
⁷ School of Physics and Institute for Superconducting and Electronic Materials, University of Wollongong, New South Wales 2522, Australia.

Abstract

Pulsed lasers operating in the mid-infrared (3-20 μm) are important for a wide range of applications in sensing, spectroscopy, imaging and communications. Despite recent advances with mid-infrared gain platforms, the lack of a capable pulse generation mechanism remains a significant technological challenge. Here we show that bulk Dirac fermions in molecular beam epitaxy grown crystalline Cd₃As₂, a three-dimensional topological Dirac semimetal, constitutes an exceptional ultrafast optical switching mechanism for the mid-infrared. Significantly, we show robust and effective tuning of the scattering channels of Dirac fermions via an element doping approach, where photocarrier relaxation times are found flexibly controlled over an order of magnitude (from 8 ps to 800 fs at 4.5 μm). Our findings reveal the strong impact of Cr doping on ultrafast optical properties in Cd₃As₂ and open up the long sought parameter space crucial for the development of compact and high-performance mid-infrared ultrafast sources.

Publication types

Research Support, Non-U.S. Gov't