Heterogeneous THz quantum cascade lasers: Broadband operation

摘要

We demonstrate the operation of broadband heterogeneous terahertz quantum cascade lasers by carefully designing sub-stacks to align at the same field. Time domain spectroscopy measurements confirm that a flat gain spectrum is present and when incorporated into metal-metal waveguides we find broadband operation over 380 GHz when metal-metal ridges with non-vertical side-walls are used.