Ultrasensitive nonlinear absorption response of large-size topological insulator and application in low-threshold bulk pulsed lasers.
Ultrasensitive nonlinear absorption response of large-size topological insulator and application in low-threshold bulk pulsed lasers.
复制标题
大尺寸拓扑绝缘体超灵敏非线性吸收响应及其在低阈值体脉冲激光器中的应用
DOI：
10.1038/srep14856
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发表时间：
2015-10-07
影响因子：
4.6
通讯作者：
Tu CY
中科院分区：
文献类型：
--
作者：
Xu JL;Sun YJ;He JL;Wang Y;Zhu ZJ;You ZY;Li JF;Chou MM;Lee CK;Tu CY
Dirac类拓扑绝缘体因其独特的性质在光电领域引起了人们的极大兴趣。本文首次报道了纯拓扑绝缘体Bi_2 Te_3对光激发具有超灵敏的非线性吸收响应。横向尺寸为几微米的Bi_2Te_3薄膜在1.0和1.3 μm处的饱和吸收强度分别只有1.1 W/cm ~ 2。利用这种灵敏的响应，在1.0 μ mNd：YVO 4激光器中实现了阈值吸收泵浦功率仅为31 mW的调Q脉冲激光输出。据我们所知，这是调Q固态体激光器的最低阈值。在平均功率为26.1mW的情况下，观察到97 ns的脉冲持续时间。实现了1.3 μm的调Q激光输出，脉宽为93 ns。此外，还演示了锁模操作。这些结果表明Bi_2Te_3是一种很有前途的用于构建宽带、小型、集成化、低功耗的高能脉冲激光系统的光学器件。我们的工作为二维材料基宽带超灵敏光电探测器和其他光电器件的发展指明了一条潜在的重要途径。
Dirac-like topological insulators have attracted strong interest in optoelectronic application because of their unusual and startling properties. Here we report for the first time that the pure topological insulator Bi2Te3exhibited a naturally ultrasensitive nonlinear absorption response to photoexcitation. The Bi2Te3sheets with lateral size up to a few micrometers showed extremely low saturation absorption intensities of only 1.1 W/cm2at 1.0 and 1.3 μm, respectively. Benefiting from this sensitive response, a Q-switching pulsed laser was achieved in a 1.0 μm Nd:YVO4laser where the threshold absorbed pump power was only 31 mW. This is the lowest threshold in Q-switched solid-state bulk lasers to the best of our knowledge. A pulse duration of 97 ns was observed with an average power of 26.1 mW. A Q-switched laser at 1.3 μm was also realized with a pulse duration as short as 93 ns. Moreover, the mode locking operation was demonstrated. These results strongly exhibit that Bi2Te3is a promising optical device for constructing broadband, miniature and integrated high-energy pulsed laser systems with low power consumption. Our work clearly points out a significantly potential avenue for the development of two-dimensional-material-based broadband ultrasensitive photodetector and other optoelectronic devices.