Features of Superradiance in a Cyclotron Quantum-Dot Heterolaser Under Continuous Pumping

Abstract

We study the generation of femtosecond superradiance (SR) pulses under continuous pumping, caused by the collective recombination of electron-hole (eh) pairs in quantum wells placed into a strong magnetic field that is perpendicular to the quantum-well plane. Such a superradiant semiconductor laser can operate even at room temperature owing to the complete quantization of the moving particles, the maximum possible spectral density of carrier states, the high volume density of effective cyclotron quantum dots, and the partial suppression of intraband scattering. In a multilayer laser heterostructure having an optical confinement factor of the order of 0.2 and located in a magnetic field of 10-50 T, generation of a quasi-periodic or chaotic sequence of coherent pulses with a peak power about 1 W, pulse duration about 100 fs, and a period-to-duration ratio of order 10 is expected. It is shown that dichromatic superradiant generation of a pair of modes resonant to two neighboring transitions between the corresponding electron and hole Landau levels is possible over a broad range of pumping powers. We performed numerical and analytical studies of monochromatic and dichromatic superradiance thresholds including studies with allowance for their modification caused by inhomogeneous broadening due to thickness fluctuations of the quantum wells and barriers in actual heterostructures.