Ciano Chiara, Virgilio Michele, Bagolini Luigi, Baldassarre Leonetta, Pashkin Alexej, Helm Manfred, Montanari Michele, Persichetti Luca, Di Gaspare Luciana, Capellini Giovanni, Paul Douglas J, Scalari Giacomo, Faist Jèrome, De Seta Monica, Ortolani Michele
Opt Express. 2020 Mar 2;28(5):7245-7258. doi: 10.1364/OE.381471.
We study radiative relaxation at terahertz frequencies in n-type Ge/SiGe quantum wells, optically pumped with a terahertz free electron laser. Two wells coupled through a tunneling barrier are designed to operate as a three-level laser system with non-equilibrium population generated by optical pumping around the 1→3 intersubband transition at 10 THz. The non-equilibrium subband population dynamics are studied by absorption-saturation measurements and compared to a numerical model. In the emission spectroscopy experiment, we observed a photoluminescence peak at 4 THz, which can be attributed to the 3→2 intersubband transition with possible contribution from the 2→1 intersubband transition. These results represent a step towards silicon-based integrated terahertz emitters.
我们研究了在太赫兹自由电子激光光泵浦下，n型锗/硅锗量子阱中太赫兹频率的辐射弛豫。通过隧道势垒耦合的两个量子阱被设计成一个三能级激光系统，通过在10太赫兹的1→3子带间跃迁附近进行光泵浦产生非平衡载流子分布。通过吸收饱和测量研究了非平衡子带载流子分布动力学，并与数值模型进行了比较。在发射光谱实验中，我们在4太赫兹处观察到一个光致发光峰，这可归因于3→2子带间跃迁，可能还有2→1子带间跃迁的贡献。这些结果代表了迈向基于硅的集成太赫兹发射器的一步。
