The subject matter consisting of an improved quantumcasadelaser

摘要

The disclosed improved quantum cascade (QC) laser comprises features that facilitate lasing at temperatures above 260 K, preferably above 300 K. Among the features is a wavefunction-increasing feature that enhances the amplitude of the lasing level wavefunction in the adjacent upstream barrier layer, thereby increasing carrier injection efficiency into the lasing level. Exemplarily, the wavefunction-increasing feature is an approximately disposed thin quantum well. Among the features typically is also a chirped superlattice in the injection/relaxation region that acts as a Bragg reflector to suppress escape of carriers from the lasing level in the continuum, while facilitating carrier extraction from the ground state into a miniband, with the energy width of the miniband decreasing over at least a portion of the thickness of the injection/relaxation region.