High-speed modulation of terahertz quantum cascade lasers by acoustic phonon pulses

The fast modulation of lasers is a fundamental requirement for applications in optical communications, high-resolution spectroscopy and metrology. Here, we report a new mechanism to modulate the emission from a terahertz frequency quantum cascade laser (QCL) device , whereby optically-generated acoustic phonon pulses are used to perturb the QCL bandstructure, enabling fast amplitude modulation that can be controlled using the QCL drive current or strain pulse amplitude. We show that this modulation can be explained using a perturbation theory analysis.