Sun Yue, Meng Yafei, Dai Ruihong, Yang Yunkun, Xu Yongbing, Zhu Shining, Shi Yi, Xiu Faxian, Wang Fengqiu
Opt Lett. 2019 Sep 1;44(17):4103-4106. doi: 10.1364/OL.44.004103.
In this Letter, we successfully introduce a long-lived non-radiative photocarrier decay component in a Dirac semimetal CdAs thin film via Mn doping. The long-lived decay component is found to vary between 200 ps and 2.8 ns with different Mn concentrations and probing wavelengths. Most remarkably, the elongated transients persist over the important mid-infrared wavelengths (observed up to 4 μm). Saturable absorption measurement reveals stronger modulation effects for long-width pulses (∼80 ps) from the Mn-doped samples. Our results provide new insights into the effect of transition-metal doping on the ultrafast optical properties of Dirac semimetal CdAs and establish CdAs as a highly amendable material for mid-infrared photonic applications.
在本信函中，我们通过锰掺杂成功地在狄拉克半金属CdAs薄膜中引入了一种长寿命的非辐射光载流子衰减成分。发现该长寿命衰减成分在不同的锰浓度和探测波长下，在200皮秒至2.8纳秒之间变化。最值得注意的是，这种延长的瞬态在重要的中红外波长范围内持续存在（观察到高达4微米）。饱和吸收测量表明，来自锰掺杂样品的长宽度脉冲（约80皮秒）具有更强的调制效果。我们的结果为过渡金属掺杂对狄拉克半金属CdAs超快光学性质的影响提供了新的见解，并将CdAs确立为一种非常适合中红外光子应用的材料。
