High-Speed Modulation of a Terahertz Quantum Cascade Laser Using Coherent Acoustic Phonon Pulses

We demonstrate a new method for high-speed modulation of terahertz emission and electronic transport of a Ga(Al)As quantum cascade laser using coherent acoustic phonon pulses. The modulation, which is on the order of 6%, can be partially explained by a perturbation-theory analysis. The <; 1 ns rise time of the modulation is dominated by parasitic device impedance in our experiment, however, the fast transit of phonons through the QCL heterostructure imply modulation rates > 100 GHz are possible.