2025/11/30 by Shakeri, Abuzar, Avaz Zadeh , Simine
#Laser #Optical gain #Quantum dots #Quantum wells #Spintronic
paper · doi:10.57647/j.jtap.2025.1906.60
In this research, we explore the similar features of quantum dots and quantum wells that function as the optical gain materials in lasers. By utilizing the method of analogy, it allows for a clearer and more analytical interpretation of quantum well lasers, which are more complex than quantum dot lasers. To establish an intuitive picture of conventional lasers with spin-unpolarized carriers and, subsequently, include the influence of spin polarization in spin-lasers, we use a simple bucket model , previously considered only for conventional lasers . Water added to the bucket represents the injection of carriers in the laser, while the water coming out corresponds to the emitted light. The small holes represent carrier losses by spontaneous recombination and the large opening near the top depicts the lasing threshold. In the article, we first discuss the time-dependent rate equations and occupation probabilities related to the rate equations model for classical and spin states of quantum dot lasers and quantum well lasers. The crucial insight in linking the two types of lasers is that the effect of restricted capture time in quantum dot laser function can be accurately mirrored by a suitable choice of the gain compression coefficient in quantum well lasers. Next, we present the two classes of analogies concerning the steady state and dynamical operation separately and explain their restrictions. Finally, we examine the differences between these two analogy models, since the two analogies are not identical, and we extend the correlation to spin lasers