2016/02/29 by Chunhui Zhu, Fengqiu Wang, Yafei Meng +14
Engineering · Physics and Astronomy · #Advanced Fiber Laser Technologies #Band gap #Condensed matter physics #Dirac (video compression format) #Dirac fermion #Doping #Fermion #Infrared #Laser #Laser-Matter Interactions and Applications #Materials science #Optics #Optoelectronics #Physics #Quantum mechanics #Semimetal #Solid State Laser Technologies #Ultrashort pulse #cond-mat.mtrl-sci #physics.optics
paper · pdf · doi:10.1038/ncomms14111
17 pages, 3 figures
arxiv created 2016/02/29 · arxiv updated 2016/12/19 · openalex publication_date 2017/01/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
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 Cd 3 As 2 , 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 Cd 3 As 2 and open up the long sought parameter space crucial for the development of compact and high-performance mid-infrared ultrafast sources.