Hai Ting, Xie Guoqiang, Ma Jie, Shao Hezhu, Qiao Zhen, Qin Zhipeng, Sun Yue, Wang Fengqiu, Yuan Peng, Ma Jingui, Qian Liejia
School of Physics and Astronomy, Key Laboratory for Laser Plasmas (Ministry of Education), Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai, 200240, China.
Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou, 221116, China.
ACS Nano. 2021 Apr 27;15(4):7430-7438. doi: 10.1021/acsnano.1c00842. Epub 2021 Mar 23.
The existing pulsed laser technologies and devices are mainly in the infrared spectral region below 3 μm so far. However, longer-wavelength pulsed lasers operating in the deep mid-infrared region (3-20 μm) are desirable for atmosphere spectroscopy, remote sensing, laser lidar, and free-space optical communications. Currently, the lack of reliable optical switches is the main limitation for developing pulsed lasers in the deep mid-infrared region. Here, we demonstrate that topological semimetal antimonene possesses an ultrabroadband optical switch characteristic covering from 2 μm to beyond 10 μm. Especially, the topological semimetal antimonene shows a very low saturable energy fluence (only 3-15 nJ cm beyond 3 μm) and an ultrafast recovery time of ps level. We also demonstrate stable Q-switching in fiber lasers at 2 and 3.5 μm by using topological semimetal antimonene as passive optical switches. Combined with the high environmental stability and easy fabrication, topological semimetal antimonene offers a promising optical switch that extends pulsed lasers into deep mid-infrared region.
到目前为止，现有的脉冲激光技术和装置主要处于3μm以下的红外光谱区域。然而，工作在深中红外区域（3 - 20μm）的长波长脉冲激光器对于大气光谱学、遥感、激光雷达和自由空间光通信来说是很有必要的。目前，缺乏可靠的光开关是在深中红外区域开发脉冲激光器的主要限制因素。在此，我们证明拓扑半金属锑烯具有覆盖从2μm到超过10μm的超宽带光开关特性。特别是，拓扑半金属锑烯显示出非常低的饱和能量通量（在3μm以上仅为3 - 15 nJ/cm²）和皮秒级的超快恢复时间。我们还通过使用拓扑半金属锑烯作为被动光开关，在2μm和3.5μm的光纤激光器中演示了稳定的调Q。结合高环境稳定性和易于制造的特点，拓扑半金属锑烯提供了一种有前景的光开关，可将脉冲激光器扩展到深中红外区域。
