光泵调制掺杂阶梯量子阱THz激光器瞬态动力学的Monte Carlo模拟

Monte Carlo Simulation of Transient Dynamics in Optically Pumped Terahetz Laser Based on Stepped Modulation Doped Quantum Well

采用系综Monte Carlo(EMC)方法首次对光泵量子阱THz激光器的载流子瞬态动力学进行了分析.提出的器件原型为三能级调制掺杂GaAs/GaxAl(1-x)As系列非对称阶梯量子阱,激射频率为6.1THz.模拟中包括了电子-电子、电子-光学声子和电子-声学声子等散射机制,采用调制掺杂以得到较高电子密度可以忽略电子-电离杂质散射.已报道的研究工作都是在量子阱中掺杂,而对于这种器件原型能否得到电子布居反转,报道的结果也是相互矛盾.器件原型在温度为77K,光泵强度达到一定值时可以得到电子布居反转,所得到的研究结果对相关的实验研究具有一定的指导意义.

Transient dynamics is a key issue for optically pumped quantum well THz laser,which is analyzed for the first time in this paper based on an ensemble Monte Carlo simulation（EMC）.The prototype designed is a 3-level stepped modulation doped GaAs/GaxAl（1-x）As quantum well.In this EMC there are electron-electron（e-e）,electron-optical phonon and electron-acoustic phonon scatterings included,and the electron-ionized impurity scattering can be ignored due to modulation doping.The reported THz prototypes of 3-level stepped quantum well were all based on doping in the deepest quantum well,and inconsistent conclusions were drown about the population inversion.We find that population inversion is found in our designed device prototype with temperature 77K and at certain pumping flux.