Development of practical theoretical calculation of semiconductor-laser gain including many-body Coulomb interactions and its experimental verifications with high-quality quantum-wire lasers

半导体激光器的光学增益是用基于自由电子近似的能带理论进行实际计算的。在本研究中，我们引入了平均场近似方法来研究二维量子阱系统和一维量子线系统中载流子间的多体库仑相互作用。根据k-p微扰理论，通过确定计算参数，编制了实用计算程序，定量计算了激光器的模式增益。我们还发展了忽略屏蔽对库仑相互作用的波数依赖性的简化计算方法。在实验中，我们精确地测量了一个高质量的三周期T型量子线激光器样品的增益谱随载流子密度的变化。通过理论和实验结果的比较，验证了理论的有效性。

Optical gain in semiconductor lasers has practically been calculated with band theories based on free electron approximations. In this study, we introduced mean-field approximations for many-body Coulomb interactions among carriers in two-dimensional quantum well system and one-dimensional quantum wire system. We developed practical calculation codes, and quantitatively calculated mode gain of the lasers by determining calculation parameters on the basis of the k-p perturbation theory. We also developed simplified calculation method by neglecting the wave-number dependence of screening for the Coulomb interactions. In the experiments, we precisely measured carrier density dependence of the gain spectrum in a 3 period T-shaped quantum-wire-laser sample with high quality. By comparing the peak gain values and quantitative gain spectra obtained with the theories and experiments, we verified the usefulness of the developed theories.