Realization of High-Performance and Farinfrared/Teraherz Quantum Cascade Lasers through Electron-Scattering Control

电子散射控制是实现高性能远红外/太赫兹量子级联激光器（qcl）的关键，有望成为环境气体监测和生命科学领域的光源。电子散射的信息可以通过研究量子微电子管的线增强因子α和相对强度噪声（RIN）来获得。α的测量为我们提供了导带子带的非抛物线性和布洛赫增益的知识。我们可以通过测量RIN对光输出功率和温度的依赖来获得非辐射弛豫时间的信息。我们还分析了用于实现远红外/太赫兹qcl的对角跃迁小带结构。由于电子-电子散射与四次幂成正比，光学跃迁与波函数重叠的平方成正比，因此可以使用对角跃迁来减少电子-电子散射。

Control of electron scattering is a key to achieve high-performance and farinfrared/terahertz quantum cascade lasers (QCLs) which are expected as light sources applicable to environmental gas monitoring and life science. Information on the electron scattering can be obtained by investigating the line enhancement factor α and relative intensity noise (RIN) of QCLs. Measurement of α provided us the knowledge of the non parabolicity of subbands in the conduction band and the Bloch gain. We could gain information on nonradiative relaxation time through the measurement of RIN dependence on optical output power and temperatures. We also analyzed a diagonal transition miniband structure for realizing farinfrared/terahertz QCLs. Since electron-electron scattering is proportional to the fourth power and optical transition the square of the overlap of wave functions, it is possible to reduce electron-electron scattering by using the diagonal transition.