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

Authors

Chunhui Zhu, Nanjing University
Fengqiu Wang, Nanjing UniversityFollow
Yafei Meng, Nanjing University
Xiang Yuan, Nanjing University
Faxian Xiu, Nanjing University
Hongyu Luo, University of Electronic Science and Technology of China
Yazhou Wang, University of Electronic Science and Technology of China
Jianfeng Li, University of Electronic Science and Technology of China
Xinjie Lv, Nanjing University
Liang He, Nanjing University
Yongbing Xu, Nanjing University
Junfeng Liu, South University of Science and technology of China
C Zhang, University of WollongongFollow
Yi Shi, Nanjing University
Rong Zhang, Nanjing University
Shining Zhu, Nanjing University

RIS ID

112012

Publication Details

Zhu, C., Wang, F., Meng, Y., Yuan, X., Xiu, F., Luo, H., Wang, Y., Li, J., Lv, X., He, L., Xu, Y., Liu, J., Zhang, C., Shi, Y., Zhang, R. & Zhu, S. (2017). A robust and tuneable mid-infrared optical switch enabled by bulk Dirac fermions. Nature Communications, 8 14111-1-14111-7.

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.