Temperature dependent nonlinear response of quantum cascade structures

Abstract

Current response and gain spectrum of a terahertz quantum cascade laser is analyzed at different temperatures by a non equilibrium Green's functions approach. The simulations are compared to recent results of time domain spectroscopy. Being able to retrieve higher harmonics of the response function, nonlinear phenomena in quantum cascade lasers are studied theoretically. For different temperatures, gain is simulated under operating conditions and related to the intensity inside the cavity, showing the degradation of performance with temperature. Resolving the electron densities in energy, shows the breakdown of inversion at high intensities.

Analysis of the effects of temperature and the electric field on quantum cascade laser characteristics

“…The NEGF method Pereira 2008, 2009;Pereira 2011;Lindskog et al 2014;Winge and Wacker 2014) which considers scattering such as energy dissipation and momentum relaxation as well as coherent effects such as multibarrier tunneling and correlation effects is an accurate approach to model the carrier transport in a quantum cascade structure.…”