Ultrafast optical nonlinearities of type II AlxGa1−xAs/AlAs multiple quantum wells
Ultrafast optical nonlinearities of type II AlxGa1−xAs/AlAs multiple quantum wells
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II 型 AlxGa1−xAs/AlAs 多量子阱的超快光学非线性
DOI：
10.1063/1.103382
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发表时间：
1990
影响因子：
4
通讯作者：
K. Ploog
中科院分区：
文献类型：
--
作者：
J. Feldmann;E. Göbel;K. Ploog
我们对II型AlxGa1−xAs/AlAs多量子阱直接带隙附近的暂态光学非线性进行了实验研究。光学非线性在带隙激子跃迁中的响应与激光光子能量密切相关。由于快速空间Γ-X转移后激子共振的碰撞展宽增强，激子共振下部的漂白吸收在室温下完全恢复，时间常数为皮秒。我们的结果表明，在第二类结构中，基于激子非线性的光学器件的本征响应比第一类结构快得多。
We present experimental studies of the transient optical nonlinearities near the direct band gap of type II AlxGa1−xAs/AlAs multiple quantum wells. The response of the optical nonlinearity at the band‐gap excitonic transition is critically dependent on laser photon energy. A complete recovery of the bleached absorption in the lower part of the excitonic resonance with a picosecond time constant at room temperature occurs due to an enhanced collision broadening of the excitonic resonance after the fast spatial Γ–X transfer. Our results demonstrate that the intrinsic response of optical devices based on exciton nonlinearities can be much faster in type II structures as compared to type I structures.