Ultrafast spin-lasers
Ultrafast spin-lasers
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DOI：
10.1038/s41586-019-1073-y
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发表时间：
2019-04-11
期刊：
影响因子：
64.8
通讯作者：
Gerhardt, Nils C.
中科院分区：
文献类型：
--
作者：
Lindemann, Markus;Xu, Gaofeng;Gerhardt, Nils C.
激光具有无处不在的应用和作为模型系统的角色，其中非平衡和合作现象可以被阐明(1)。因此，在激光操作中引入新概念有可能导致新的应用和基本见解(2)。自旋电子学(3)，其中自旋和电子的电荷都被使用，导致了自旋激光器的发展，其中利用了电荷载流子自旋和光子自旋。在这里，我们通过实验证明，在普通半导体激光器中载流子自旋和光偏振之间的耦合可以使室温调制频率超过200千兆赫兹，比最好的传统半导体激光器高出近一个数量级。令人惊讶的是，由此产生的自旋激光器的超快操作依赖于短的载流子自旋弛豫时间和大的折射率各向异性，这两者通常被认为是有害的自旋电子学(3)和传统激光器(4)。我们的研究结果克服了传统直接调制激光器的关键速度限制，为下一代低能量超快光通信提供了前景。
Lasers have both ubiquitous applications and roles as model systems in which non-equilibrium and cooperative phenomena can be elucidated(1). The introduction of novel concepts in laser operation thus has potential to lead to both new applications and fundamental insights(2). Spintronics(3), in which both the spin and the charge of the electron are used, has led to the development of spin-lasers, in which charge-carrier spin and photon spin are exploited. Here we show experimentally that the coupling between carrier spin and light polarization in common semiconductor lasers can enable room-temperature modulation frequencies above 200 gigahertz, exceeding by nearly an order of magnitude the best conventional semiconductor lasers. Surprisingly, this ultrafast operation of the resultant spin-laser relies on a short carrier spin relaxation time and a large anisotropy of the refractive index, both of which are commonly viewed as detrimental in spintronics(3) and conventional lasers(4). Our results overcome the key speed limitations of conventional directly modulated lasers and offer a prospect for the next generation of low-energy ultrafast optical communication.